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Geant4 Simulation :MCP PET

4’’(102mm)

Scintillator( LSO)

4’’(102mm)

10mm

Glass( Borosilicate)

PhotocathodeI(Carbon)

Space(Vacuum)

MCP(Alumina)

Space(Vacumm)

Trans-Line(Gold)

Isolator(Alumina)

Ground(Copper)

Scintillator

MCP Assembly

MCP Assembly

0.060’’

0.002’’

0.040’’

0.200’’

0.040’’

0.035mm

0.400mm

0.025mm

Air Gap 0.001’’

9.15mm

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Simulation Setup

113.2mm

28.3mm

102m

m(4

’’)

511keV 2 gamma

50mm

Scintillator : LSO, LaBr3

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# of photoelectron at photo-cathode

•# of p.e at 1st layer•Sum of 2 sides( front and back)•371 for LSO 976 for LaBr3( ~2.6 times larger than LSO)•LaBr3 has more compton scattering events.

# of p.e ( LSO) LaBr3

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Single Electron Responses

1. Pulse Shape ~500ps rise time(top) ( real measurement by J-F, 18 p.e) similar value for falling time assume asymmetric gausian shape

2. Average gain factor : 10e6 Single electron gain ~70% in FWHM.

3. Transit Time Spread sigma = 50ps.

Simulated pulse shape

real measurement

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Readout Scheme

TL direction

Front Side( -> Extract X cor) Back Side(-> Extract Y cor)

•Readout signals from 24 horizontally (vertically) running TLs. • TL : 4mm width, 4.25mm pitch.•Total 384(24 TL x 2 ends/TL x 2 sides x 4layers) channels for a module.

•Position : 5 TL energy weight •Energy : Sum of two sides( e.g, 5 TL sum w.r.t the maximum for each side)•Timing : Average of maximum TL from each side.

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Sample pulses(LaBr3)

TL#7 TL#8 TL#9

TL#10 TL#11 TL#12

TL#13 TL#14 TL#15

Layer#0Front sideOne end.# of p.e = 259

Beam:Middle of TL#11 & TL#12

mV

ns

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Pulse( close-up) ( LaBr3)

mV

ns

TL#11 TL#12

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Energy resolution(LaBr3)

pC

Sum of 5 TLs( around the maximum)

Integrated Charge.10^6 gain50ohm termination.

~24% of effi.Around 511keV peak.( > 130pC)

~9% FWHMEnergy resol. at 511keV.

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Position(LaBr3)

A) X = 0mm B) X = 2.125mm C) X = 4.25mm

Recon. X(peak) 0.05mm 2.14mm 4.24mm

A) Beam X = 0mm B) Beam X = 2.125mm C) Beam X = 4.25mm

Position : Energy weighted of 5 TLs (w.r.t the maximum energy TL.)

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Coincidence Timing resolution(LaBr3)

Event time:Average of 4 timing1. Finid first non-zero signal layer.2. Find maximum signal TL.3. Apply 5mV threshold, Leading Edge.

Top: ~1ns FWHM ( ~62% eff.)Before energy cut

Bottom : 375ps FWHM ( 6.7% eff.)Select the event around 511keV energy.Energy > 130( pC)

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Summary

1. Four layers of MCPs+Scintillator

2. Continuous Scintillator( 4’’x4’’)

( LaBr3 , LSO)

3. 4.25mm pitch ( 4.0+0.25) of TLs.

4. Energy : ~9% at 511keV

CoincidenceTiming : ~375ps ( ~7% effi.)

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Backup: Pulse shape( LSO)

Layer#0Front sideOne end.# of p.e = 90

Beam:Middle of TL#11 & TL#12