ESRFStatus of In-Vacuum undulators at ESRF
1- Installed IDs
2- In-Vacuum undulators
3-Magnetic design
4- Magnetic measurements
5- Future
ESRF ID group & Technical services
ESRFHistory of ESRF IDs
ESRF IDs
0
10
20
30
40
50
60
70
80
12/8/1991 24/12/1992 8/5/1994 20/9/1995 1/2/1997 16/6/1998 29/10/1999 12/3/2001 25/7/2002 7/12/2003 20/4/2005 2/9/2006
Date
Nu
mb
er
of
seg
men
ts
5
7
9
11
13
15
17
19
21
23
Avera
ge m
in.
Gap
[m
m]
nb of seg.min gap
November 2003: 68 ID segments installed- 5 in-vacuum undulators (8 in January 2004)- 9 wigglers & asymmetric wigglers- 6 helical undulators ≈
ESRFStatus of in-vacuum undulators
SS Period [mm] L [m] Status
ID11 23 1.6 Jan 99ID22 23 2 July 01
ID9 17 2 July 01
ID29 21 2 Dec 02
ID13 18 2 July 02
ID11 22 2 Dec 2003ID30 23 2 Dec 2003ID30 23 2 Dec 2003
- 5 devices in operation: min. gap 6 mm (5 mm for ID11) - 3 devices ready for installation in December 2003
ESRFOperation of installed In-Vacuum IDs
• Low field Integrals (`≈ 20 G.cm ) for all gap settings are confirmed by regular COD measurements => No correction coils.
• Very small (≈ 5.0e-4) tune shift in multi bunches, 16 bunches, Hybrid user operation
• Some small impedance or tune shift effects observed with all in-vacuum undulator closed in high current single bunch (to be investigated with additional devices).
• Gaps under full user control
<10 % lifetime reduction @ gap 5 mm (uniform & 2/3 filling mode)
40
45
50
55
60
65
70
75
0 5 10 15 20gap [mm]
Acceptable for future operation
@ gap 5 mm
ESRFMagnetic Designs
Soft iron pole
Magnet block
6 devices based on P.P.M. technologyPeriods 17, 18, 21 & 23 mm
1 hybrid device constructed- Period 22 mm
Higher peak field than p.p.m≈ 15-20% forGap/period= 0.25-0.3 (6/22)
Development of
dedicated field correctionmethods
Permanent magnet material : Sm2Co17, Br=1.03 - 1.05 T
ESRFMagnetic measurements (1)
1.0
0.8
0.6
0.4
0.2Effe
ctiv
e pe
ak fi
eld
[T]
28242016128Gap [mm]
2.0
1.5
1.0
0.5
Deflection param
eter K
Measured fieldHybrid U22
- Excellent agreement between calculations (RADIA) and measurements (≈ 1%)
- K= 2.14 @ gap 5 mm
20
16
12
8
4
Gai
n [%
]
0.800.700.600.500.400.30Gap/Period
Gain= (Bh-Bp)/Bp
Bh: hybrid effective peak field (n=1)
Bp: P.P.M peak field (≈ n=1)
ESRFMagnetic Measurements (2)
-0.2
-0.1
0.0
0.1
Fiel
d In
t. [G
.m]
3025201510Gap [mm]
Hybrid U22 Hor. Vert.
P.P.M U23
Hor. Vert.
Field integral correction:- more complicated than p.p.m devices but workable
-many improvements identified (design & field processing)
-Ambient field in SR ≠ in ID lab
--> change field integrals vs gap
--> need active correction (steerer)
On axis
-0.8
-0.6
-0.4
-0.2
0.0
0.2
2nd
Fiel
d in
t. [G
m**
2]
3025201510Gap [mm]
Hybrid U22 Hor. Vert.
P.P.M U23
Hor. Vert.
On axis
ESRFMagnetic Measurements (3)
-0.8
-0.4
0.0
0.4
0.8V
ert.
Fiel
d [T
]
2.42.22.01.81.61.41.21.00.80.60.40.20.0Long. position [m]
U22Gap 6mm
-0.8µm
-0.4
0.0
0.4
0.8
Tran
sv. p
ositi
on [µ
m]
2.42.01.61.20.80.40.0Longitudinal position [m]
Hor. Vert
ESRFMagnetic measurements (4)
4x1018
3
2
1
0
Ang
ular
Flu
x [P
hot./
s/0.
1%/m
rad2 ]
100806040200Photon Energy [KeV]
Error free undulator Actual undulatorHybrid undulator
Period 22 mmL=2 mGap 6 mm
2.8
2.6
2.4
2.22.0
1.8
1.6
1.4
R.m
.s. P
hase
Err
or [d
eg.]
302826242220181614121086Gap [mm]
Hybrid U22 (ID11)P.P.M. U23 (ID30)
R.m.s phase error
Phase shimming
E=6 GeV
I=0.2 A
Filament e beam
Correction of phase error:
-Methods for p.p.m. & hybrid are similar
-the results are also similar
ESRFSummary
Hybrid technology for in-vacuum undulators
In- vacuum undulator U22
-higher peak field than p.p.mis confirmed-> 20 % @ gap/period= 0.25
Field integral shimming & phase shimming are accessiblebut can be optimized with:
-modifications on the mechanicaldesign of the magnetic assembly
-implementation of dedicated numerical tools for hybrid devices
--> room for numerous improvements
ESRFESRF In-Vacuum undulators: tomorrow (1)
Permanent magnet devices1- Update hybrid design for in-vacuum undulators
- mechanical parts of magnetic assembly- field processing & numerical simulations
2- Construction of 2 new hybrid devices- U20 (ID9, 2nd in-vacuum device)- U22 (ID6, test undulator)
Purpose of ID6 U22
Evaluation of potential radiation damage on Sm2Co17 material
-operate permanently @ gap 5 mm
-record regularly spectrum on highharmonics (n=9,11) sensitive to radiation damage
ESRFESRF In-Vacuum undulators: tomorrow (2)
Superconducting devices2.5
2.0
1.5
1.0
0.5
0.0
Fiel
d [T
]
20181614121086Period [mm]
Max. Field ComputedNbTi @ 4.2 Deg KGap = 5 mm
Measurement Anka & Accel
R. Rossmanith et al, EPAC2002
In-vacuum Undulator Gap = 5 mm
Rossmanith et al. ANKA/ACCEL PAC03
Higher peak field-smaller period
Test of a prototype at ESRF foreseen
Partial funding by EC under negotiation
• Magnetism– field calculation– Field correction …
• Cryogenic aspects– Heat budget …
• Low vessel pressure when both cold and warm– Baking ..
• Electron Beam Dynamics , routine operation
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