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New particle ID detector for Crystal Ball at MAMI-C. Daniel Watts, Daria Sokhan, Claire Tarbert University of Edinburgh John Annand, Douglas Macgregor, Evie Downie, J McGeorge University of Glasgow. PID-I. Constraints of MWPC-I and targets → siting of PMTs at downstream end - PowerPoint PPT Presentation
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New particle ID detector for Crystal
Ball at MAMI-CDaniel Watts, Daria Sokhan, Claire Tarbert
University of Edinburgh
John Annand, Douglas Macgregor, Evie Downie, J McGeorgeUniversity of Glasgow
• Constraints of MWPC-I and targets → siting of PMTs at downstream end
• Design specifications
• Good separation of p, with little overhead in material before MWPC and CB detectors
PID-I
MWPC-II & PID-II
• MWPC-II redesigned for MAMI-C experiments • PID-II outside MWPC inbetween the MWPC chambers → Opted for setup similar to PID-I
• But PMTs at upstream end - TAPS
• rPID-II >rPID-I
• Keep same segmentation (24)
• tscint = 4mm (PID-I: 2mm)
PID-II schematic
CB Tunnel PID-II scintillators
MWPCsupports
MWPCChambers
PMTs
M
WP
C =
133
mm
500mm
PMT support ring
beam
• PID-II – removable! (redesigned MWPC connectors)
PID-II schematic
P
ID(I
NN
ER
) =
108
.4m
m
Hamamatsu H3164 - 10
Active detectorregion
PID-II test module – light attenuation• 90Sr beta source
• Observe position of landau as source moved along scintillator → light attenuation
PID-II Test modulePID-I Test module
Enhancement near PMT
Distance from PMT (mm)
Po
siti
on
of
lan
dau
pea
k (
arb
un
its)
PID-II GEANT Simulation
• Use PID-I simulation parameters – light output, light collection efficiency, QE …→ Reasonable agreement with experimental data
• Include increase in PID-II scintillator thickness
Flat KE distributionup to 0.7 GeV
Isotropic angular distribution
No shower shaperestrictions
Pions K+
Protons
Energy deposited in CB (GeV)
En
erg
y d
ep
os
ite
d i
n P
ID-I
I (G
eV
)
1 2 3 4 5 6Delivery of scint.
Cutting & prep of scint.
Lightguide manufacture
Element assembly & tests
Detector assembly & tests
Total construction time ~ 5.2 months
Implementation into MWPC & CB
months
PID-II – schedule and status
Present status
Delivery of PMTs
• Manufacture/delivery of PID-II components complete
• Module testing completed in ~2 weeks
• Completed detector ready in early June
Summary
Liquid hydrogentarget
Radius mwpc = 66.5cm
PID-II
• PID-I support ring
router-rinner = 14mm
• 4 mm clearance each side
to the polarised target.
Hydrogen target will have
problem – clearance = 0mm!
65.5
51,5
PID-II & polarised target
PID-II PMTs
• Same tubes and bases as for PID-I
• BUT use new packaged tube + base assemblies -include magnetic shield
Hamamatsu H3164 - 10
Very preliminary decay gammas from nucleon knockout
12C(,ppp)9Li
Q value
Low energyclusters from shaded region
2.69 MeV
E=400-500 MeV
Simulated + signals in Crystal Ball
No restriction on shower size ≤ 2 crystals in + shower
+ decay
Nuclear interaction
Incident + energy (GeV)
Hig
hest
clu
ster
ene
rgy
(GeV
)
Very preliminary decay gammas from nucleon knockout
12C(,ppp)
Q value
Low energyclusters from shaded region
2.69 MeV
• rPID-II >rPID-I
• Same segmentation (24)
• Lscint chosen to give PID
Info for all proposed targets
• Lscint =50 cm (PID-I 32cm)
PID-II – schedule and status
PID-II Test modulePID-I Test module
New polarised target design