PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.
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Transcript of PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.
![Page 1: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/1.jpg)
PyEcloud code and simulationsG. Iadarola, G. Rumolo
ICE meeting 9 April 2012
![Page 2: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/2.jpg)
Outline
• A few basic concepts on e-cloud build-up
• PyEcloud: How do we simulate the e-cloud build-up
o Flow-chart
o MP size management
o Convergence and performances
• Overview of e-cloud studies for CERN accelerators:
o e-cloud studies for the PS and SPS
o e-cloud studies for the LHC
25ns observation benchmarking for the arcs
e-cloud build-up in in 800mm common pipe near IP2
![Page 3: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/3.jpg)
Outline
• A few basic concepts on e-cloud build-up
• PyEcloud: How do we simulate the e-cloud build-up
o Flow-chart
o MP size management
o Convergence and performances
• Overview of e-cloud studies for CERN accelerators:
o e-cloud studies for the PS and SPS
o e-cloud studies for the LHC
25ns observation benchmarking for the arcs
e-cloud build-up in in 800mm common pipe near IP2
![Page 4: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/4.jpg)
Secondary electron emission
e-
![Page 5: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/5.jpg)
Secondary electron emission
e-
![Page 6: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/6.jpg)
Secondary electron emission
![Page 7: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/7.jpg)
Secondary electron emission
![Page 8: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/8.jpg)
Secondary electron emission
![Page 9: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/9.jpg)
Secondary electron emission
![Page 10: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/10.jpg)
Secondary electron emission
![Page 11: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/11.jpg)
Secondary electron emission
![Page 12: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/12.jpg)
Secondary electron emission
The Secondary Electron Yield of the chamber’s surface is basically the ratio between
emitted and impacting electrons and is function of the energy of the primary
electron.
0 200 400 600 800 10000.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Primary e- energy [eV]S
ec
on
da
ry E
lec
tro
n Y
ield
[S
EY
]
![Page 13: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/13.jpg)
Secondary electron emission
The Secondary Electron Yield of the chamber’s surface is basically the ratio between
emitted and impacting electrons and is function of the energy of the primary
electron.
0 200 400 600 800 10000.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Primary e- energy [eV]S
ec
on
da
ry E
lec
tro
n Y
ield
[S
EY
]
e- absorber
e- emitter
![Page 14: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/14.jpg)
Seed mechanisms
• In proton accelerators the electron cloud is typically triggered by ionization of
residual gas that is present in the beam pipe.
• In the LHC (for E>1TeV) there are many electrons coming from photoelectric
emission due to synchrotron radiation
![Page 15: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/15.jpg)
Electron cloud build-up
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
![Page 16: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/16.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
• During the bunch passage the electrons are accelerated by the beam “pinched”
at the center of the beam pipe
Electron cloud build-up
![Page 17: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/17.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• During the bunch passage the electrons are accelerated by the beam “pinched”
at the center of the beam pipe
![Page 18: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/18.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• During the bunch passage the electrons are accelerated by the beam “pinched”
at the center of the beam pipe
![Page 19: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/19.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• During the bunch passage the electrons are accelerated by the beam “pinched”
at the center of the beam pipe
![Page 20: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/20.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 21: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/21.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 22: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/22.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
Electron cloud build-up
![Page 23: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/23.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 24: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/24.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 25: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/25.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 26: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/26.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 27: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/27.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 28: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/28.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 29: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/29.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 30: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/30.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• After the bunch passage the electrons hit the chamber’s wall (with E~100eV)
• If the Secondary Electron Yield (SEY) of the surface is large enough, secondary
electrons can be generated and growth of the total number of electrons is
observed
![Page 31: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/31.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• Secondary electrons are emitted with smaller energies (E~1eV) and, if they hit
the wall before the following bunch passage, they are absorbed without
generation of further secondaries
• Decay of the total number of electrons can be observed in this stage
![Page 32: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/32.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• Secondary electrons are emitted with smaller energies (E~1eV) and, if they hit
the wall before the following bunch passage, they are absorbed without
generation of further secondaries
• Decay of the total number of electrons can be observed in this stage
![Page 33: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/33.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• Secondary electrons are emitted with smaller energies (E~1eV) and, if they hit
the wall before the following bunch passage, they are absorbed without
generation of further secondaries
• Decay of the total number of electrons can be observed in this stage
![Page 34: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/34.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• Secondary electrons are emitted with smaller energies (E~1eV) and, if they hit
the wall before the following bunch passage, they are absorbed without
generation of further secondaries
• Decay of the total number of electrons can be observed in this stage
![Page 35: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/35.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• Secondary electrons are emitted with smaller energies (E~1eV) and, if they hit
the wall before the following bunch passage, they are absorbed without
generation of further secondaries
• Decay of the total number of electrons can be observed in this stage
![Page 36: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/36.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• Secondary electrons are emitted with smaller energies (E~1eV) and, if they hit
the wall before the following bunch passage, they are absorbed without
generation of further secondaries
• Decay of the total number of electrons can be observed in this stage
![Page 37: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/37.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud build-up
• Secondary electrons are emitted with smaller energies (E~1eV) and, if they hit
the wall before the following bunch passage, they are absorbed without
generation of further secondaries
• Decay of the total number of electrons can be observed in this stage
![Page 38: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/38.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
• Another bunch passage can interrupt the decay before reaching the initial value
• In these cases avalanche multiplication is observed between bunch passages,
and an exponential growth of the number of electrons happens during the
bunch train passage
Electron cloud build-up
![Page 39: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/39.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
• Another bunch passage can interrupt the decay before reaching the initial value
• In these cases avalanche multiplication is observed between bunch passages,
and an exponential growth of the number of electrons happens during the
bunch train passage
Electron cloud build-up
![Page 40: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/40.jpg)
Beam pipe transverse cut
0 10 20 30 405
5.5
6
6.5
7
7.5
8
8.5
9x 10
9
Time [ns]N
um
ber
of
e- [
m-1
]
Electron cloud effect is strongly dependent on bunch spacing!
bunch spac.
Electron cloud build-up
![Page 41: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/41.jpg)
The electron cloud buildup
![Page 42: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/42.jpg)
The electron cloud buildup
![Page 43: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/43.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
![Page 44: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/44.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
![Page 45: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/45.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
![Page 46: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/46.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
The passage of the first bunches of the train provokes an exponential rise of the number of electron in the chamber (multipacting).
![Page 47: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/47.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
The number of e- tends to saturate to a certain value because of the space charge field generated by the electron themselves.
![Page 48: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/48.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
![Page 49: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/49.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
The e-cloud is partially lost in the gaps between batches and a short build-up is observed at the beginning of each batch passage
![Page 50: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/50.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
![Page 51: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/51.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
![Page 52: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/52.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
![Page 53: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/53.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
![Page 54: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/54.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
![Page 55: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/55.jpg)
The electron cloud buildup
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
After the passage of the train the e-cloud decays
![Page 56: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/56.jpg)
The electron cloud buildup
![Page 57: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/57.jpg)
The electron cloud buildup
![Page 58: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/58.jpg)
The electron cloud buildup
0 0.5 1 1.5 2 2.5 3
x 10-5
104
106
108
1010
t [s]
Nu
mb
er
of
e- p
er
un
it le
ng
th [
m-1
]
0 0.5 1 1.5 2 2.5 3
x 10-5
104
106
108
1010
t [s]
Nu
mb
er
of
e- p
er
un
it le
ng
th [
m-1
]
The decay can be fast enough that no memory effect is observed between turns
1st turn 2nd turn
![Page 59: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/59.jpg)
0 0.5 1 1.5 2 2.5 3
x 10-5
104
106
108
1010
t [s]
Nu
mb
er
of
e- p
er
un
it le
ng
th [
m-1
]
0 0.5 1 1.5 2 2.5 3
x 10-5
104
106
108
1010
t [s]
Nu
mb
er
of
e- p
er
un
it le
ng
th [
m-1
]
The electron cloud buildup
If the decay is slow enough or other memory effects are present a multi-turn regime can be observed
5% uncaptured beam present in the machine
1st turn 2nd turn
![Page 60: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/60.jpg)
Electron cloud distribution in a bending magnet
-0.50
0.5
-0.50
0.51
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
P
Rc
B
In a strong dipolar magnetic field, electrons perform helicoidal
trajectories around the field lines.
![Page 61: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/61.jpg)
Electron cloud distribution in a bending magnet
-0.50
0.5
-0.50
0.51
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
P
Rc
B
In a strong dipolar magnetic field, electrons perform helicoidal
trajectories around the field lines.
<1ns
<1mm
e- are confined to move along B field lines
![Page 62: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/62.jpg)
Electron cloud distribution in a bending magnet
e-
0 200 400 600 800 10000.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Primary e- energy [eV]
Se
co
nd
ary
Ele
ctr
on
Yie
ld [
SE
Y]
![Page 63: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/63.jpg)
Electron cloud distribution in a bending magnet
e-
0 200 400 600 800 10000.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Primary e- energy [eV]
Se
co
nd
ary
Ele
ctr
on
Yie
ld [
SE
Y]
![Page 64: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/64.jpg)
Electron cloud distribution in a bending magnet
e-
0 200 400 600 800 10000.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Primary e- energy [eV]
Se
co
nd
ary
Ele
ctr
on
Yie
ld [
SE
Y]
![Page 65: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/65.jpg)
Electron cloud distribution in a bending magnet
e-
0 200 400 600 800 10000.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Primary e- energy [eV]
Se
co
nd
ary
Ele
ctr
on
Yie
ld [
SE
Y]
![Page 66: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/66.jpg)
Electron cloud distribution in a bending magnet
This gives the two stripes distribution that typical for the e-
cloud in a bending magnet
![Page 67: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/67.jpg)
Outline
• A few basic concepts on e-cloud build-up
• PyEcloud: How do we simulate the e-cloud build-up
o Flow-chart
o MP size management
o Convergence and performances
• Overview of e-cloud studies for CERN accelerators:
o e-cloud studies for the PS and SPS
o e-cloud studies for the LHC
25ns observation benchmarking for the arcs
e-cloud build-up in in 800mm common pipe near IP2
![Page 68: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/68.jpg)
ECLOUD
• Analysis and prediction on the e-cloud buildup strongly relies on numerical
simulations that are typically performed with simulation tools developed ad-
hoc.
• Most of the work done at CERN in the last years has employed the ECLOUD
code (developed at CERN since 1998, mainly by G. Bellodi, O. Bruning, G.
Rumolo, D. Schulte, F. Zimmermann).
• At the very beginning our idea was to reorganize ECLOUD in order to make it
easier to develop new features, to identify and correct present and future
bugs, to access a larger amount of information about our simulations
• However…
![Page 69: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/69.jpg)
PyECLOUD
We have decided to write a new fully reorganized build-up code, in a newer and
more powerful language, considering that the initial effort would be compensated
by a significantly increased efficiency in future development and debugging.
The employed programming language is Python:
• Interpreted language (open source), allowing incremental and
interactive development of the code, encouraging an highly
modular structure
• Libraries for scientific computation (e.g Numpy, Scipy, Pylab)
• Extensible with C/C++ or FORTRAN compiled modules for
computationally intensive parts
Thanks to R. De Maria and K. Li
![Page 70: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/70.jpg)
Thanks to C. Bhat, O. Dominguez, H. Maury Cuna, F. Zimmermann
PyECLOUD
Writing PyECLOUD has required a detailed analysis of ECLOUD algorithm and
implementation, looking also at the related long experience in electron cloud simulations.
Attention has been devoted to the identification of ECLOUD limitations, in particular in
terms of its convergence properties with respect to the electron distribution in bending
magnets (how many stripes…)
As a result, several features have been significantly modified in order to improve the
code’s performances in terms:
• Reliability & Accuracy
• Efficiency
• Flexibility
![Page 71: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/71.jpg)
Macroparticles
The simulation of the dynamics of the entire number of electrons (≈1010 per meter)
is extremely heavy (practically unaffordable)
Since the dynamics equation of the electron depends only on the q/m ratio of the
electron a macroparticle (MP) method can be used:
The MP size can be seen as the “resolution” our electron gas simulation
![Page 72: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/72.jpg)
Outline
• A few basic concepts on e-cloud build-up
• PyEcloud: How do we simulate the e-cloud build-up
o Flow-chart
o MP size management
o Convergence and performances
• Overview of e-cloud studies for CERN accelerators:
o e-cloud studies for the PS and SPS
o e-cloud studies for the LHC
25ns observation benchmarking for the arcs
e-cloud build-up in in 800mm common pipe near IP2
![Page 73: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/73.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
PyEcloud flowchart
Evaluate the e- space charge electric field
![Page 74: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/74.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
PyEcloud flowchart
Evaluate the e- space charge electric field
Evaluate the number of seed e- which are
generated during the current time step and
generate the corresponding MP:
• Residual gas ionization and
photoemission are implemented
• Theoretical/empirical models are used to
determine MP space and energy
distributions
![Page 75: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/75.jpg)
x [mm]
y [
mm
]
Charge density [m-1]
-60 -40 -20 0 20 40 60
-20
-10
0
10
20
0
1
2
x 104t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
• The field map for the relevant chamber
geometry and beam shape is pre-computed
on a suitable rectangular grid and loaded
from file in the initialization stage
• When the field at a certain location is
needed a linear (4 points) interpolation
algorithm is employed
PyEcloud flowchart
![Page 76: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/76.jpg)
x [mm]
y [
mm
]
E log(normalizad magnitude) - with image charges
-60 -40 -20 0 20 40 60
-20
-10
0
10
20
-4
-3
-2
-1
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
• The field map for the relevant chamber
geometry and beam shape is pre-computed
on a suitable rectangular grid and loaded
from file in the initialization stage
• When the field at a certain location is
needed a linear (4 points) interpolation
algorithm is employed
PyEcloud flowchart
![Page 77: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/77.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
• The field map for the relevant chamber
geometry and beam shape is pre-computed
on a suitable rectangular grid and loaded
from file in the initialization stage
• When the field at a certain location is
needed a linear (4 points) interpolation
algorithm is employed
PyEcloud flowchart
![Page 78: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/78.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
x [m]
y [
m]
(x,y) [C/m2]
-0.06 -0.04 -0.02 0 0.02 0.04 0.06
-0.02
-0.01
0
0.01
0.02
-2.5
-2
-1.5
-1
-0.5
0x 10
-5
• To compute the e- space charge electric
field we employ a classical Particle In Cell
(PIC) algorithm
PyEcloud flowchart
![Page 79: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/79.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
x [m]
y [
m]
(x,y) [C/m2]
-0.06 -0.04 -0.02 0 0.02 0.04 0.06
-0.02
-0.01
0
0.01
0.02
-2.5
-2
-1.5
-1
-0.5
0x 10
-5
Poisson equation:
with on the boundary
The electric field is given by:
Electrostatic potential e- charge density
PyEcloud flowchart
![Page 80: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/80.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field The electron charge density distribution
ρ(x,y) is computed on a uniform square grid
by distributing the charge of each MP to
the nearest 4 nodes:
PyEcloud flowchart
![Page 81: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/81.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
Finite differencesmethod
PyEcloud flowchart
![Page 82: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/82.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
Finite differencesmethod
Sparse matrix depending only on the geometry (can be computed in the initialization stage and reused for all the space-charge evaluations).
PyEcloud flowchart
![Page 83: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/83.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
Central difference formulas are used to
retrieve the electric field on the nodes:
PyEcloud flowchart
![Page 84: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/84.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
• When the field at a certain location is
needed a linear (4 points) interpolation
algorithm is employed
PyEcloud flowchart
![Page 85: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/85.jpg)
x [m]
y [
m]
(x,y) [C/m2]
-0.06 -0.04 -0.02 0 0.02 0.04 0.06
-0.02
-0.01
0
0.01
0.02
-2.5
-2
-1.5
-1
-0.5
0x 10
-5
x [m]
y [
m]
(x,y) [V]
-0.06 -0.04 -0.02 0 0.02 0.04 0.06
-0.02
-0.01
0
0.01
0.02
-200
-150
-100
-50
0
x [m]
y [
m]
|E(x,y)| [V/m]
-0.06 -0.04 -0.02 0 0.02 0.04 0.06
-0.02
-0.01
0
0.01
0.02
0
5000
10000
15000
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
PyEcloud flowchart
![Page 86: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/86.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
When possible, “strong B condition” is
exploited in order to speed-up the
computation (D. Schulte)
The dynamics equation is integrated in order
to update MP position and momentum:
PyEcloud flowchart
![Page 87: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/87.jpg)
t=t+Δt
Evaluate the electric field of beam at each MP location
Generate seed e-
Compute MP motion (t->t+Δt)
Detect impacts and generate secondaries
Evaluate the e- space charge electric field
• When a MP hits the wall
theoretical/empirical models are
employed to generate charge, energy
and angle of the emitted charge
• According to the number of emitted
electrons, MPs can be simply rescaled or
new MP can be generated.
PyEcloud flowchart
![Page 88: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/88.jpg)
Outline
• A few basic concepts on e-cloud build-up
• PyEcloud: How do we simulate the e-cloud build-up
o Flow-chart
o MP size management
o Convergence and performances
• Overview of e-cloud studies for CERN accelerators:
o e-cloud studies for the PS and SPS
o e-cloud studies for the LHC
25ns observation benchmarking for the arcs
e-cloud build-up in in 800mm common pipe near IP2
![Page 89: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/89.jpg)
Macroparticle size management
0 1 2 3 4 5 6 7 8 9
x 10-6
104
106
108
time [s]Nu
mb
er
of e
- per
un
it le
ng
th [m
-1]
0 1 2 3 4 5 6 7 8 9
x 10-6
0
2
4
6
8x 10
11
time [s]Accu
m. n
um
ber
of scru
bb
. e- [
m-1
]
In an electron-cloud buildup, due to the multipacting process, the electron
number spreads several orders of magnitude:
It is practically impossible to choose a MP size that is suitable for the entire
simulation (allowing a satisfactory description of the phenomenon and a
computationally affordable number of MPs)
![Page 90: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/90.jpg)
We define a target average size of the MPs Nref which is adaptively changed
during the simulation and is used for:
1) Seed MP generation: the generated
MPs have size Nref
2) Secondary MP emission: additional
true secondary MPs are emitted if the
total emitted charge is >1.5Nref
3) MP cleaning: at each bunch passage a
clean function is called that eliminates
all the MPs with charge <10-4Nref
x
Macroparticle size management
![Page 91: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/91.jpg)
When the number of MPs becomes larger than a certain threshold (≈105) that
means that the computational burden is becoming too high, we change MP target
size (Nref ) and perform a regeneration of the MPs system:
Macroparticle size management
![Page 92: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/92.jpg)
a. Each macroparticle is assigned to a cell of a uniform grid in the 5-D space
(x,y,vx,vy,vz) obtaining an approximation of the phase space distribution
Macroparticle size management
When the number of MPs becomes larger than a certain threshold (≈105) that
means that the computational burden is becoming too high, we change MP target
size (Nref ) and perform a regeneration of the MPs system:
x [m]
y [
m]
-0.02 -0.01 0 0.01 0.02
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
x [m]
vx [
m/s
]
-0.02 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 0.02
-4
-3
-2
-1
0
1
2
3
4
x 106
![Page 93: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/93.jpg)
a. Each macroparticle is assigned to a cell of a uniform grid in the 5-D space
(x,y,vx,vy,vz) obtaining an approximation of the phase space distribution
Macroparticle size management
When the number of MPs becomes larger than a certain threshold (≈105) that
means that the computational burden is becoming too high, we change MP target
size (Nref ) and perform a regeneration of the MPs system:
x [m]
y [
m]
-0.02 -0.01 0 0.01 0.02
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
x [m]
vx [
m/s
]
-0.02 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 0.02
-4
-3
-2
-1
0
1
2
3
4
x 106
![Page 94: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/94.jpg)
y [m]
vy [
m/s
]
-0.015 -0.01 -0.005 0 0.005 0.01 0.015
-4
-3
-2
-1
0
1
2
3
4
x 106
vx [m/s]
vz [
m/s
]
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
x 106
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2x 10
6
Macroparticle size management
a. Each macroparticle is assigned to a cell of a uniform grid in the 5-D space
(x,y,vx,vy,vz) obtaining an approximation of the phase space distribution
When the number of MPs becomes larger than a certain threshold (≈105) that
means that the computational burden is becoming too high, we change MP target
size (Nref ) and perform a regeneration of the MPs system:
![Page 95: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/95.jpg)
Macroparticle size management
a. Each macroparticle is assigned to a cell of a uniform grid in the 5-D space
(x,y,vx,vy,vz) obtaining an approximation of the phase space distribution
b. The new target MP size is chosen so that:
When the number of MPs becomes larger than a certain threshold (≈105) that
means that the computational burden is becoming too high, we change MP target
size (Nref ) and perform a regeneration of the MPs system:
c. A new MPs set, having the new reference size, is generated according to
the computed distribution.
![Page 96: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/96.jpg)
Macroparticle size management
a. Each macroparticle is assigned to a cell of a uniform grid in the 5-D space
(x,y,vx,vy,vz) obtaining an approximation of the phase space distribution
b. The new target MP size is chosen so that:
When the number of MPs becomes larger than a certain threshold (≈105) that
means that the computational burden is becoming too high, we change MP target
size (Nref ) and perform a regeneration of the MPs system:
c. A new MPs set, having the new reference size, is generated according to
the computed distribution.
All moments related to position and velocity (e.g. energy distrib. , charge distrib.)
are preserved. The error on total charge and total energy does not go beyond 1-2%
![Page 97: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/97.jpg)
Outline
• A few basic concepts on e-cloud build-up
• PyEcloud: How do we simulate the e-cloud build-up
o Flow-chart
o MP size management
o Convergence and performances
• Overview of e-cloud studies for CERN accelerators:
o e-cloud studies for the PS and SPS
o e-cloud studies for the LHC
25ns observation benchmarking for the arcs
e-cloud build-up in in 800mm common pipe near IP2
![Page 98: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/98.jpg)
Convergence study - Number of electrons
0 0.5 1 1.5 2 2.5 3 3.5 4
x 10-6
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
x 109
t [s]
Nu
mb
er
of
e- p
er
un
it le
ng
th [
m-1
]
0.2ns0.1ns0.05ns0.025ns0.012ns
0 1 2 3 4 5
x 10-6
0
0.5
1
1.5
2
2.5
3x 10
9
t [s]
Nu
mb
er
of
e- p
er
un
it le
ng
th [
m-1
]
0.2ns0.1ns0.05ns0.025ns0.012ns
ECLOUD PyECLOUD
![Page 99: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/99.jpg)
20 40 60 80 100 120 140 1600
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Bunch passage
En
erg
y d
ep
os
itio
n [
W/m
]
0.2ns0.1ns0.05ns0.025ns0.012ns
20 40 60 80 100 120 140 160 180
0.5
1
1.5
2
2.5
3
3.5
Bunch passage
En
erg
y d
ep
os
itio
n [
W/m
]
0.2ns0.1ns0.05ns0.025ns
Convergence study – Heat load
ECLOUD PyECLOUD
![Page 100: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/100.jpg)
0 0.01 0.02 0.03 0.04 0.05 0.06
10-10
10-5
100
x [m]
Av
. e- c
ha
rge
hit
tin
g t
he
wa
ll [A
m-2
]
0.2ns0.1ns0.05ns0.025ns0.012ns
0 0.01 0.02 0.03 0.04 0.05 0.06
10-10
10-5
100
x [m]
Av
. e- c
ha
rge
hit
tin
g t
he
wa
ll [A
m-2
]
0.2ns0.1ns0.05ns0.025ns
Convergence study – Electrons ditribution
ECLOUD PyECLOUD
![Page 101: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/101.jpg)
0
2000
4000
6000
8000
10000
12000
14000
16000
0.200ns 0.100ns 0.050ns 0.025ns 0.012ns
ECLOUD
PYECLOUD
Timestep ECLOUD PYECLOUD
0.2 ns 29 min 12 min
0.1 ns 1h 27 min 13 min
0.05 ns 1h 45 min 24 min
0.025ns 3h 7 min 40 min
0.012ns 4h 15 min 1h 6 min
Processing time
![Page 102: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/102.jpg)
Outline
• A few basic concepts on e-cloud build-up
• PyEcloud: How do we simulate the e-cloud build-up
o Flow-chart
o MP size management
o Convergence and performances
• Overview of e-cloud studies for CERN accelerators:
o e-cloud studies for the PS and SPS
o e-cloud studies for the LHC
25ns observation benchmarking for the arcs
e-cloud build-up in in 800mm common pipe near IP2
![Page 103: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/103.jpg)
0 0.5 1 1.5 20
0.01
0.02
0.03
time [us]
e-c
lou
d s
ign
al [
a.u
. ]
Av. intensity = 1.57*1011ppb Bunch length = 15.0ns
0 0.5 1 1.5 20
2
4
6
time [us]
Pic
k-u
p s
ign
al [
a.u
.]
In the PS, the e-cloud appears only in the last stages of the RF gymnastics. A dedicated
e-cloud experiment, with a shielded pickup, is available.
E-cloud studies for the PS
Measurements with 50ns beam
Thanks to F. Caspers, S. Gilardoni, E. Mahner, C. Y. Vallgren
![Page 104: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/104.jpg)
0 0.5 1 1.5 20
0.01
0.02
0.03
time [us]
e-c
lou
d s
ign
al [
a.u
. ]
Av. intensity = 1.49*1011ppb Bunch length = 6.5ns
0 0.5 1 1.5 20
2
4
6
time [us]
Pic
k-u
p s
ign
al [
a.u
.]
In the PS, the e-cloud appears only in the last stages of the RF gymnastics. A dedicated
e-cloud experiment, with a shielded pickup, is available.
E-cloud studies for the PS
Measurements with 50ns beam
Thanks to F. Caspers, S. Gilardoni, E. Mahner, C. Y. Vallgren
![Page 105: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/105.jpg)
0 0.5 1 1.5 20
0.01
0.02
0.03
time [us]
e-c
lou
d s
ign
al [
a.u
. ]
Av. intensity = 1.47*1011ppb Bunch length = 4.0ns
0 0.5 1 1.5 20
2
4
6
time [us]
Pic
k-u
p s
ign
al [
a.u
.]
In the PS, the e-cloud appears only in the last stages of the RF gymnastics. A dedicated
e-cloud experiment, with a shielded pickup, is available.
E-cloud studies for the PS
Measurements with 50ns beam
Thanks to F. Caspers, S. Gilardoni, E. Mahner, C. Y. Vallgren
![Page 106: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/106.jpg)
0 0.5 1 1.5 20
0.05
0.1
time [us]
e-c
lou
d s
ign
al [
a.u
. ]
Av. intensity = 1.15*1011ppb Bunch length = 15.0ns
0 0.5 1 1.5 20
2
4
time [us]
Pic
k-u
p s
ign
al [
a.u
.]
E-cloud studies for the PS
In the PS, the e-cloud appears only in the last stages of the RF gymnastics. A dedicated
e-cloud experiment, with a shielded pickup, is available.
Measurements with 25ns beam
Thanks to F. Caspers, S. Gilardoni, E. Mahner, C. Y. Vallgren
![Page 107: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/107.jpg)
0 0.5 1 1.5 20
0.05
0.1
time [us]
e-c
lou
d s
ign
al [
a.u
. ]
Av. intensity = 1.15*1011ppb Bunch length = 6.5ns
0 0.5 1 1.5 20
2
4
time [us]
Pic
k-u
p s
ign
al [
a.u
.]
In the PS, the e-cloud appears only in the last stages of the RF gymnastics. A dedicated
e-cloud experiment, with a shielded pickup, is available.
Measurements with 25ns beam
E-cloud studies for the PS
Thanks to F. Caspers, S. Gilardoni, E. Mahner, C. Y. Vallgren
![Page 108: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/108.jpg)
0 0.5 1 1.5 20
0.05
0.1
time [us]
e-c
lou
d s
ign
al [
a.u
. ]
Av. intensity = 1.15*1011ppb Bunch length = 4.0ns
0 0.5 1 1.5 20
2
4
time [us]
Pic
k-u
p s
ign
al [
a.u
.]
In the PS, the e-cloud appears only in the last stages of the RF gymnastics. A dedicated
e-cloud experiment, with a shielded pickup, is available.
Measurements with 25ns beam
E-cloud studies for the PS
Thanks to F. Caspers, S. Gilardoni, E. Mahner, C. Y. Vallgren
![Page 109: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/109.jpg)
0 0.5 1 1.5 20
0.2
0.4
0.6
0.8
1
Time [us]
Ele
ctr
on
clo
ud
ind
ica
tor
[a.u
]
PyECLOUD simulation0 0.5 1 1.5 2
0
0.2
0.4
0.6
0.8
1
Time [us]
e-c
lou
d s
ign
al [
a.u
.]
Measurement
In the PS, the e-cloud appears only in the last stages of the RF gymnastics. A dedicated
e-cloud experiment, with a shielded pickup, is available.
Benchmarking of these data with simulations is ongoing:
E-cloud studies for the PS
![Page 110: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/110.jpg)
E-cloud studies for the SPS
• Clear indications of e-cloud activity along the ring with 25ns beam (basically
pressure rise)
• E-cloud mitigation is considered necessary to improve the machine performances
(LIU) -> aC coating is the baseline
• Simulation and machine studies are ongoing to identify which parts of the machine
need to be coated and to optimize the scrubbing process for the other components
Thanks to:H. Bartosik, F. Caspers, M. Driss Mensi, B. Goddard, H. Neupert, M. Taborrelli,E. Shaposhnikova
![Page 111: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/111.jpg)
E-cloud studies for the SPS
1.5 2 2.5 3 3.51
1.2
1.4
1.6
1.8
2M
ulti
pa
cti
ng
th
res
ho
ld ( m
ax)
Beam intensity [ppb]
50ns - 26GeV50ns - 450GeV25ns - 26GeV25ns - 450GeV
1.5 2 2.5 3 3.51
1.2
1.4
1.6
1.8
2
Mu
ltip
ac
tin
g t
hre
sh
old
( m
ax)
Beam intensity [ppb]
50ns - 26GeV50ns - 450GeV
25ns - 26GeV25ns - 450GeV
1.5 2 2.5 3 3.51
1.2
1.4
1.6
1.8
2
Mu
ltip
ac
tin
g t
hre
sh
old
( m
ax)
Beam intensity [ppb]
50ns - 26GeV50ns - 450GeV
25ns - 26GeV25ns - 450GeV
1.5 2 2.5 3 3.51
1.2
1.4
1.6
1.8
2
Mu
ltip
ac
tin
g t
hre
sh
old
( m
ax)
Beam intensity [ppb]
50ns - 26GeV50ns - 450GeV25ns - 26GeV25ns - 450GeV
![Page 112: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/112.jpg)
E-cloud studies for the SPS
Different e-cloud experiments are available (Strip detectors, shielded pickup, aC coated
magnets and straight sections). Much data collected during 2012 Scrubbing Run and
MD session. Analysis and simulation benchmarking is ongoing.
0 1 2 3 4 5 6 7
-0.01
0
0.01
Be
am
sig
na
l
Time [s]
0 1 2 3 4 5 6 7
-0.2
0
0.2
0.4
e-c
lou
d s
ign
al
Time [s]
Example of shielded pickup measurement
![Page 113: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/113.jpg)
E-cloud studies for the SPS
Different e-cloud experiments are available (Strip detectors, shielded pickup, aC coated
magnets and straight sections). Much data collected during 2012 Scrubbing Run and
MD session. Analysis and simulation benchmarking is ongoing.
Strip-detector measurements on MBA profile
![Page 114: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/114.jpg)
Outline
• A few basic concepts on e-cloud build-up
• PyEcloud: How do we simulate the e-cloud build-up
o Flow-chart
o MP size management
o Convergence and performances
• Overview of e-cloud studies for CERN accelerators:
o e-cloud studies for the PS and SPS
o e-cloud studies for the LHC
25ns observation benchmarking for the arcs
e-cloud build-up in in 800mm common pipe near IP2
![Page 115: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/115.jpg)
25ns tests in the LHC
0 5 10 15 20 25 30 35 40 45 50 550
5
10
15
20x 10
13
Inte
nsi
ty
Time [h]
0 5 10 15 20 25 30 35 40 45 50 55
0
10
20
30
40
Time [h]
Hea
t lo
ad [
W/h
cell
]
S12S23S34S45S56S67S78S81
DATE SHORT DESCRIPTION
29 June Injections of 9 x 24b trains per beam with different spacings between them
26 August Two attempts to inject a 48b train with damper on and off: fast instability dumps the beam within 500 turns in both cases (SBI and CBI)
7 October High chromaticity (Q’x,y ≈15): Injection tests with trains of 72-144-216-288 bunches from the SPS + ramp to 3.5 TeV & 5h store with 60b (12+24+24) per beam
14 October High chromaticity: injection of up to 1020 bunches per beam in 72b trains (decreasing spacings between trains at each fill: 6.3–3.2–1 ms)
24-25 October Injection of up to 2100 bunches in Beam 1 and 1020 in Beam 2 (1ms train spacing)
Scrubbing
29/06 07/10 24-25/1014/10
Beam 1 Beam 2 Energy
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Simulation approach
• The entire beam with measured bunch intensities and bunch lengths has been simulated:
From FBCT
From BQM
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• The entire beam with measured bunch intensities and bunch lengths has been simulated:
From FBCT
From BQM
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• The entire beam with measured bunch intensities and bunch lengths has been simulated:
From FBCT
From BQM
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29/06 07/10 24-25/1014/10
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Thanks to S. Clodet, L. Tavian
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Six snapshots from the 25ns MDs to reproduce the measured heat load by simulations!
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dmax has decreased from the initial 2.1 to 1.52 in the arcs !
25ns threshold @450 GeV
25ns threshold @3.5 TeV
29/06 07/10 24-25/1014/10
50ns
2011 scrubbing history of LHC arcs
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Bunch energy loss
Simulations dmax fixed to 1.5(added 2e9p+/m uncapt. beam)
Measurements the energy loss per bunch is obtained from the stable phase shift
Beam 1
ZOOM
Thanks to J. E. Muller, E. Shaposhnikova
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Thanks to J. E. Muller, E. Shaposhnikova
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Outline
• A few basic concepts on e-cloud build-up
• PyEcloud: How do we simulate the e-cloud build-up
o Flow-chart
o MP size management
o Convergence and performances
• Overview of e-cloud studies for CERN accelerators:
o e-cloud studies for the PS and SPS
o e-cloud studies for the LHC
25ns observation benchmarking for the arcs
e-cloud build-up in in 800mm common pipe near IP2
![Page 125: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/125.jpg)
800mm vacuum chamber @ IP2
Vacuum team has reported pressure rise in 800mm common vacuum chambers
on both sides of ALICE, with significant impact on background
Ø 20cm
Ø 80cm
27m
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Vacuum observations
Pressure measurements in the 800mm chambers on both sides of ALICE
1092 1380Number of bunches per beam1236
ALICE polarity flip seems to cause further worsening of vacuum quality followed by a slow conditioning
Thanks to O. Dominguez, V. Baglin
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Fill 1960 19-20/07/2011
Ramp
Vacuum observations
Thanks to O. Dominguez, V. Baglin
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Fill 1960 19-20/07/2011
To check if our model of e-cloud can explain the observed behavior of
pressure rise, we have simulated the electron cloud build up in the
800mm chamber before and after the last two injections
Simulated conditions
800mm chamber – two beams simulations
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2nd turn1st turn LSS2
Before the last two injections (144 bunches per injection) about 1/4 of each ring is still empty
800mm chamber – two beams simulations
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Before the last two injections (144 bunches per injection) about 1/4 of each ring is still empty
800mm chamber – two beams simulations
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Before the last two injections (144 bunches per injection) about 1/4 of each ring is still empty
800mm chamber – two beams simulations
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Before the last two injections (144 bunches per injection) about 1/4 of each ring is still empty
800mm chamber – two beams simulations
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Before the last two injections (144 bunches per injection) about 1/4 of each ring is still empty
800mm chamber – two beams simulations
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800mm chamber – two beams simulations
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800mm chamber – two beams simulations
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Before the last two injections (144 bunches per injection) about 1/4 of each ring is still empty
800mm chamber – two beams simulations
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e-cloud buildup is observed when both beams are passing in the 800mm chamber
800mm chamber – two beams simulations
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2nd turn1st turn LSS2
e-cloud buildup is observed when both beams are passing in the 800mm chamber
800mm chamber – two beams simulations
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e-cloud buildup is observed when both beams are passing in the 800mm chamber
800mm chamber – two beams simulations
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e-cloud buildup is observed when both beams are passing in the 800mm chamber
800mm chamber – two beams simulations
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e-cloud buildup is observed when both beams are passing in the 800mm chamber
800mm chamber – two beams simulations
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e-cloud buildup is observed when both beams are passing in the 800mm chamber
800mm chamber – two beams simulations
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e-cloud buildup is observed when both beams are passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 144: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/144.jpg)
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A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 145: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/145.jpg)
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A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 146: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/146.jpg)
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A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 147: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/147.jpg)
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A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 148: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/148.jpg)
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A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 149: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/149.jpg)
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A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 150: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/150.jpg)
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2nd turn1st turn LSS2
A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 151: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/151.jpg)
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2nd turn1st turn LSS2
A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 152: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/152.jpg)
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2nd turn1st turn LSS2
A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 153: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/153.jpg)
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2nd turn1st turn LSS2
A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 154: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/154.jpg)
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2nd turn1st turn LSS2
A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 155: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/155.jpg)
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2nd turn1st turn LSS2
A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 156: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/156.jpg)
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2nd turn1st turn LSS2
A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 157: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/157.jpg)
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2nd turn1st turn LSS2
A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 158: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/158.jpg)
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2nd turn1st turn LSS2
A slow decay of the e-cloud is observed when only one 50ns beam is passing in the 800mm chamber
800mm chamber – two beams simulations
![Page 159: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/159.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 160: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/160.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 161: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/161.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 162: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/162.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 163: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/163.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 164: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/164.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 165: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/165.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 166: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/166.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 167: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/167.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 168: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/168.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 169: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/169.jpg)
0 20 40 60 80 100 120 140 1600
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 170: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/170.jpg)
0 20 40 60 80 100 120 140 1600
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 171: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/171.jpg)
0 20 40 60 80 100 120 140 1600
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 172: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/172.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 173: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/173.jpg)
0 20 40 60 80 100 120 140 1600
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 174: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/174.jpg)
0 20 40 60 80 100 120 140 1600
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 175: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/175.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 176: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/176.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 177: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/177.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 178: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/178.jpg)
0 20 40 60 80 100 120 140 1600
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 179: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/179.jpg)
0 20 40 60 80 100 120 140 1600
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1.6
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Time [s]
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mb
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-1]
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 180: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/180.jpg)
0 20 40 60 80 100 120 140 1600
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2x 10
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Time [s]
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mb
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 181: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/181.jpg)
0 20 40 60 80 100 120 140 1600
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mb
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 182: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/182.jpg)
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mb
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 183: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/183.jpg)
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 184: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/184.jpg)
0 20 40 60 80 100 120 140 1600
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2x 10
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mb
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 185: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/185.jpg)
0 20 40 60 80 100 120 140 1600
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1
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mb
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 186: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/186.jpg)
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0.2
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1
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2x 10
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Time [s]
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mb
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2nd turn1st turn LSS2
No memory effect between following turns is observed
800mm chamber – two beams simulations
![Page 187: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/187.jpg)
Fill 1960 19-20/07/2011
To check if our model of e-cloud can explain the observed behavior of
pressure rise, we have simulated the electron cloud build up in the
800mm chamber before and after the last two injections
Simulated conditions
800mm chamber – two beams simulations
![Page 188: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/188.jpg)
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0.2
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1
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2x 10
9
Time [s]
Nu
mb
er o
f e
- per
un
it l
en
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[m
-1]
1/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 189: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/189.jpg)
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Time [s]
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-1]
2/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 190: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/190.jpg)
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Time [s]
Nu
mb
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un
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[m
-1]
3/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 191: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/191.jpg)
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Time [s]
Nu
mb
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un
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[m
-1]
4/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 192: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/192.jpg)
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Time [s]
Nu
mb
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f e
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it l
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[m
-1]
5/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 193: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/193.jpg)
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Time [s]
Nu
mb
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[m
-1]
6/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 194: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/194.jpg)
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Time [s]
Nu
mb
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it l
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[m
-1]
7/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 195: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/195.jpg)
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Time [s]
Nu
mb
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it l
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[m
-1]
8/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 196: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/196.jpg)
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Time [s]
Nu
mb
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[m
-1]
9/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 197: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/197.jpg)
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Time [s]
Nu
mb
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f e
- per
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it l
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[m
-1]
10/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 198: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/198.jpg)
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Time [s]
Nu
mb
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it l
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[m
-1]
11/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 199: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/199.jpg)
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Time [s]
Nu
mb
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[m
-1]
12/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 200: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/200.jpg)
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Time [s]
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-1]
13/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 201: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/201.jpg)
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Time [s]
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mb
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-1]
14/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 202: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/202.jpg)
0 20 40 60 80 100 120 140 1600
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1
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Time [s]
Nu
mb
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it l
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[m
-1]
15/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 203: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/203.jpg)
0 20 40 60 80 100 120 140 1600
0.2
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1
1.2
1.4
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2x 10
9
Time [s]
Nu
mb
er o
f e
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-1]
16/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
16/31
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 204: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/204.jpg)
0 20 40 60 80 100 120 140 1600
0.2
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1
1.2
1.4
1.6
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2x 10
9
Time [s]
Nu
mb
er o
f e
- per
un
it l
en
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[m
-1]
17/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 205: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/205.jpg)
0 20 40 60 80 100 120 140 1600
0.2
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1
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2x 10
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Time [s]
Nu
mb
er o
f e
- per
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it l
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[m
-1]
18/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 206: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/206.jpg)
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2x 10
9
Time [s]
Nu
mb
er o
f e
- per
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it l
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[m
-1]
19/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 207: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/207.jpg)
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Time [s]
Nu
mb
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f e
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it l
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[m
-1]
20/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 208: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/208.jpg)
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1
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Time [s]
Nu
mb
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it l
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[m
-1]
21/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 209: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/209.jpg)
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Time [s]
Nu
mb
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it l
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[m
-1]
22/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 210: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/210.jpg)
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Time [s]
Nu
mb
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it l
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[m
-1]
23/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 211: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/211.jpg)
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Time [s]
Nu
mb
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[m
-1]
24/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 212: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/212.jpg)
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Time [s]
Nu
mb
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[m
-1]
25/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 213: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/213.jpg)
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Time [s]
Nu
mb
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[m
-1]
26/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 214: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/214.jpg)
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Time [s]
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mb
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[m
-1]
27/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 215: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/215.jpg)
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1
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Time [s]
Nu
mb
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[m
-1]
28/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 216: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/216.jpg)
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Time [s]
Nu
mb
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[m
-1]
29/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 217: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/217.jpg)
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0.2
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1
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2x 10
9
Time [s]
Nu
mb
er o
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it l
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[m
-1]
30/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 218: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/218.jpg)
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0.2
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1
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2x 10
9
Time [s]
Nu
mb
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it l
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[m
-1]
31/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 219: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/219.jpg)
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0.2
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1
1.2
1.4
1.6
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2x 10
9
Time [s]
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mb
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-1]
32/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 220: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/220.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 221: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/221.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 222: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/222.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 223: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/223.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 224: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/224.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 225: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/225.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 226: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/226.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 229: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/229.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 230: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/230.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 231: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/231.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 232: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/232.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 233: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/233.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 235: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/235.jpg)
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Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 236: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/236.jpg)
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49/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 237: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/237.jpg)
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50/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 238: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/238.jpg)
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51/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 239: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/239.jpg)
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52/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 240: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/240.jpg)
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53/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 241: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/241.jpg)
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-1]
54/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 242: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/242.jpg)
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Time [s]
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-1]
55/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 243: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/243.jpg)
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Time [s]
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-1]
56/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 244: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/244.jpg)
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Time [s]
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-1]
57/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
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Time [s]
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58/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 246: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/246.jpg)
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Time [s]
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-1]
59/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 247: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/247.jpg)
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Time [s]
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60/61
Last 2 inj. missing
Complete 1380 b. fill. scheme
2nd turn1st turn LSS2
At the end of injection the two rings look quite completely filled, the largest holes being the two abort gaps
800mm chamber – two beams simulations
![Page 248: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/248.jpg)
2nd turn
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Time [s]
Nu
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ng
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]
Last 2 inj. missingComplete 1380 b. fill. scheme
1st turn
Memory effect is observed between turns, which can strongly enhance the electron cloud
800mm chamber – two beams simulations
LSS2
![Page 249: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/249.jpg)
Future work / Wish list
• Arbitrary externally assigned magnetic/electric field maps (quadrupole,
combined function magnet, clearing electrode)
• Non elliptical boundary condition on chamber’s wall
• Non uniform secondary electron yield (including EC detector simulation)
• Integration with the HEADTAIL code for a self consistent model
• Benchmarking with machine observations and measurements (collected
and to be collected)
• Parallelization (GPU?)
x [mm]
y [
mm
]
Charge density [m-1]
-60 -40 -20 0 20 40 60
-20
-10
0
10
20
0
1
2
x 104
PyEcloud
HEADTAIL
![Page 250: PyEcloud code and simulations G. Iadarola, G. Rumolo ICE meeting 9 April 2012.](https://reader038.fdocuments.us/reader038/viewer/2022103006/56649efd5503460f94c10b78/html5/thumbnails/250.jpg)
Thanks for your attention!