New particle ID detector for Crystal
Ball at MAMI-CDaniel Watts,
University of Edinburgh
John Annand1, B. Briscoe3, A. Clarkson2, Evie Downie1, D. Glazier2, S. Lumsden2, Daria Sokhan2, C McGeorge1,Claire Tarbert2
1- University of Glasgow2- University of Edinburgh
3- George Washington university
• 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
1 2 3 4 5 6 7 8Delivery 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
Delivery of PMTs
~1.5 month delay - Replacement of scintillator strips. New batch of manufactured by ELJEN
7
PMTs
Scintillator
HV inputand signal readout
3He target noseAl support
ring
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
)
3 day old bananas - all PID2 elements
1 2 3 4 5 6
7 8 9 10 11 12
13 14 15 16 1817
19 20 21 22 23 24
Data from 3He target - NO restriction or correction for path length in the scintillator
CB Energy (MeV)
PID
2 E
ber
gy
(a.u
)
Pro
ton
pu
nch
th
rou
gh
• Detector ready for use
Summary
Data from first test
• PID Trigger – CH2 target
• All 24 elements give good signals
PID2Protons
Pions
PID1
Liquid hydrogentarget
Radius mwpc = 66.5cm
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)
CB Tunnel PID-II
Scintillatorsinner = 116.4mm
MWPCsupports
MWPCChambers
PMTs
M
WP
C =
133
mm
(ou
ter
dia
mete
r of
PID
su
pp
ort
rin
g)
500mm scintillator length
PMT support ring
beam
P
ID(I
NN
ER
) =
108
.4m
m (
inn
er
dia
mete
r of
PID
rin
g)
Hamamatsu H3164 - 10
Plastic downstreamscintillator supportinner = 113.25mm
(For detail seeadditional
figure)
Chamber length (between the supports) = 570 mm
Schematic of PID-II for use with the Crystal Ball@MAMI-CD. Watts 20/04/06
BEAM
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
Preliminary decay gammas from nucleon knockout
12C(,ppp)9Li
Q value
Low energyclusters from shaded region
2.69 MeV
E=400-500 MeV
i=1
3
• Also look at pp, 4p, 5p … knockout
Missing Energy (MeV) = E–Tpi –Trec
Energy of cluster (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