Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm John Malcolm John
Simulation of charged particles traversing the RICH photon detectors.
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
Direction of Cherenkov Photons incident on the photocathode.
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
Absorption/Reflection atphotocathode modeled from
Born & Wolf derivation using:
nphotocathode = 2.7 + 1.5i , thickness = 23nm(measured from EMI bialkali photocathodes)
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
Number of photoelectronscreated for one saturated
track through a curved HPD window..
DiameterActive diam.
ThicknessRad. of curv.
= 127mm= 114mm= 4mm= 100mm
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
10GeV/c passing intothe front face of the HPD
at 15o to the normal.
Side view (zoom)
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
10GeV/c passing throughthe back of the HPDat 5o to the normal.
Side view (zoom)
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
10GeV/c passing throughthe curved HPD window
at 85o to the normal.WORST CASE !!!! - but very rare.
Isometric projection
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
The photoelectron hit patterns resulting from the standalone window simulation are plugged directly into SICb.
One of 18 different patterns is chosen depending on the angle the particle makes with the curved window.
Photons falling outside the 11cm tube diameter are killed.
The number of photoelectrons included in the pattern is modified by the sin2C factor. - However 99% of tracks are fully saturated because of the high refractive index of glass/quartz.
Parameterisation in SICb of particles traversing HPDs.
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
SICb Event display.2 BsDs events.
11cm diameter HPD.
Red dots are the plugged patterns parameterising the effect of traversing charged particles.
Blue dots are the normal Cherenkov photons.
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
Standalone study of an MaPMT with 25mm quartz lens also done.
10 GeV/c at 60o to the photocathode normal.
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
25mm2, 25mm thick Rad. of Curv. =25mm
10 GeV/c at 180o to the photocathode normal.
10 GeV/c at 0o to the photocathode normalcoming out of the tube.
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
Number of photoelectons created with a 10 GeV/c traversing a 25mm thick
quartz MaPMT lens.
length
radius
(c)
(b)
(a)
(a) Photoelectrons created.(b) Photoelectrons collected into a pixel.(c) Number of hit pixels.
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
Effect of charged particles traversing the photon detectors
on the pattern recognition performance.
The pattern recognition algorithm now includes a second iteration using the result of the first iteration as an improved estimate of the local background.
This had been written (GW) to allow the pattern recognition to cope with photon clusters from tracks going backwards in the gas radiators.
This improved algorithm has been used with the traversing particle parameterisation included to assess the new effect.
No other explicit modifications to the algorithm have been made at this time.
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
Performance of the PatternRecognition Algorithm.11cm diameter HPDs.
848
25
6
2
0
35
4
2
4
12
272
0
30
34
33
41
0
753
7
8
13
893
11
32
106
316
6600
38
4
107
5
107
9
9
1
9
e K p X
Prob( K,p) = 0.6 ± 0.1 %
e
K
p
X
rec.true
Prob( K,p,X) = 2.3 ± 0.2 %
Prob(K ,,e) = 3.1 ± 0.8 % 1.6 %
2.4 %
0.4 %
For 300 BsDs-((K+K-) -) +
(no trav.particleparam.)
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
Performance of the PatternRecognition Algorithm.
MaPMTs with lens.
858
17
13
1
0
28
0
1
3
7
283
0
16
37
43
62
0
732
1
7
11
923
4
18
79
278
6712
34
1
68
4
108
13
0
0
6
e K p X
Prob( K,p) = 0.5 ± 0.1 %
e
K
p
X
rec.true
Prob( K,p,X) = 1.5 ± 0.2 %
Prob(K ,,e) = 2.1 ± 0.5 % 1.1 %
1.6 %
0.5 %
(no trav.particleparam.)
For 300 BsDs-((K+K-) -) +
Simulation of charged particles traversing the LHCb RICH photon detectorsSimulation of charged particles traversing the LHCb RICH photon detectors Malcolm JohnMalcolm John
Conclusion
A parameteristion of charged particles traversing the RICH photon detectors has been included in SICb for PAD-HPD geometry and MaPMT (with lens).
The existing pattern recognition copes well with the new effect included.
Parameterization should be reviewed later in light of testbeam results.
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