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A Design of a PET detector using Micro-channel Plate PMT with Transmission Line ReadoutTransmission Line Readout

Contents1. Introduction2 Material and Methods2. Material and Methods3. Experimental Tests4. Simulation Results5 S & Pl

Heejong Kim

5. Summary & Plans

1

Heejong KimDepartment of Radiology, University of Chicago, IL

1 Introduction1. IntroductionPositron Emission Tomography (PET)d t t t 511k V h t f ihil tidetect two 511keV photons from e+ annihilation.

Most of PET instrument• Scintillator + Photo-detector + DAQ electronics• Scintillator + Photo-detector + DAQ electronics

Photomultiplier tube (PMT) has been widely usedPhoto-detector in PET instrumentation.

• Fast response time• High sensitivity• Stability• Bulky• Bulky • Sensitive to magnetic field

PET detector improvements in photo-detector

2

p p(keep light output as much as large/fast)

• SiPM, High Q.E PMT, ….• Micro-channel Plate PMT

A block detector module.from HRRT, CTI(Siemens)

Micro-channel Plate PMT

photonFaceplate

Photocathode

Dual MCPPhotoelectron

p

ΔV ~ 200V

ΔV ~ 2000V

Anode

Gain ~ 106

ΔV ~ 200V

MCP-OUT Pulse

(from Paul Hink’s slide at 2008 picosecond workshp)Photonis XP85022 MCP-PMT(2”x2”, 14mm thickness)

•Faster time response Large Area Picosecond Photo-Dectector (LAPPD) project•Faster time response•Compact size•Position sensitive•Expensive cost

Large Area Picosecond Photo Dectector (LAPPD) project• Aiming to develop large area (8”x8”) MCP-PMT• Collaboration of Univ. of Chicago, Argonne, Fermilab,….• Estimates a factor of ~10 cheaper than PMT per area.

3

pWhen available, it can be applicable to PET instrument.

• Various PET design would be possibleat reasonable cost.

Existing PETs using MCP-PMTExisting PETs using MCP-PMT

Developed for mobile cardiac PET25cm x 25 cm field of view.N I ( 5 5 12 5 3 5 5 it h)

(from David Brasse’s slide)LYSO ( 1.5 x 1.5 x 25 mm3) NaI ( 5 x 5 x 12.5mm3, 5.5mm pitch)

Use 16 MCP-PMT( Photonis XP85002)4 pads in each MCP-PMT.

A Weisenberger et al

LYSO ( 1.5 x 1.5 x 25 mm )Use Photonis XP85023 MCP.( 1024 anodes)

S. Salvador et al.,

4

A. Weisenberger et al,IEEE NSS/MIC Record 2007, p.3705

S. Salvador et al.,IEEE TNS, V56, 2009, p.17

2 Materials and Methods2. Materials and Methods

Investigated the feasibility of a PET design usingInvestigated the feasibility of a PET design using large area MCP-PMT by simulation study.

Simulation parameters were not optimized yetSimulation parameters were not optimized yet.

Design FeaturesDesign FeaturesSimulation Configuration and SetupGeant4 with optical photon processGeant4 with optical photon process

MCP-PMT modelTransmission Line Readout

5

Transmission Line Readout

PET Design Features (simulation)g ( )

LSO(LYSO) scintillator( )High Light yield (25000~30000/MeV)Fast decay time (~40ns)

Micro-channel Plate (MCP) PMT. (4”x4” area)Position sensitiveness.Fast time response.Compact size than conventional PMT

Transmission Line readout schemeTransmission Line readout scheme.Readout both ends of the strip.Position measurement by time differenceEfficient reduction of # of readout channel (NxN -> 2N)c e t educt o o o eadout c a e ( )

Readout at both ends (Scintillator sandwiched by MCPs)Possible to extract Depth of Interaction (DOI)

6

Detector Configuration (simulation)g ( )

Two detector modules facing each other.Two detector modules facing each other.8 cm distance between them.

One detector module consists of 24x24 array of LSO scintillator and

Back MCP/TL Front MCP/TL

24x24 array of LSO scintillator and 2 MCP/TL assemblies.

LSO pixel dimension : 4x4x25mm3.pCrystal pitch : 4.25mm

MCP assembly dimension : 102x102x9 15mm3 (4”x4” of area)102x102x9.15mm3. (4 x4 of area)It includes photocathode and TL structure.

MCP is coupled to LSO LSO scintillator array

7

at both front and back ends.

Optical Photon Simulationp

O ti l Ph t ti d t tOptical Photon generation and transport was simulated by Geant4.Two 511keV gammas are generated back to back g gat the middle of two detector modules and sent to the detector centres.The reflective media was inserted between crystalsThe reflective media was inserted between crystals.The surface between LSO and MCP glass was optically coupled with the optical grease. LSO characteristics (simulation input parameters)

Light yield : 30,000/MeV Decay time : 40ns

8

yRe solution : 10.4%( FWHM)

Simulation Flow (in each Event)Simulation Flow (in each Event)

Wavelength (nm)350 400 450 500 550 600

Rel

ativ

e Fr

eque

ncy

0

0.2

0.4

0.6

0.8

1

1.2

w/o Q.E

w/ Q.E

(b)

Wavelength (nm)350 400 450 500 550 600

Rel

ativ

e Fr

eque

ncy

0

0.2

0.4

0.6

0.8

1

1.2

w/o Q.E

w/ Q.E

(b)•511 KeV gamma interaction at LSO•Photo-electric effect, Compton Scattering

O i l h d

Wavelength (nm)350 400 450 500 550 600

Rel

ativ

e Fr

eque

ncy

0

0.2

0.4

0.6

0.8

1

1.2

w/o Q.E

w/ Q.E

(b)

•Optical photons generatedreflection, refraction, absorption•Detected at photo-cathode of MCP-PMT•For each event optical photon’s

Wavelength (nm)350 400 450 500 550 600

Rel

ativ

e Fr

eque

ncy

0

0.2

0.4

0.6

0.8

1

1.2

w/o Q.E

w/ Q.E

(b)

•For each event, optical photon sEnergy (wavelength), Arrival time, Positionwere recorded (ntuple)•ROOT format

Wavelength (nm)350 400 450 500 550 600

Rel

ativ

e Fr

eque

ncy

0

0.2

0.4

0.6

0.8

1

1.2

w/o Q.E

w/ Q.E

(b)

•ROOT format

•Off-line analysis•Applying Q.E of MCPOptical photon spectrum from LSO

9

pp y g Q•……

p p p

Signal Read-out SchemeS g a ead out Sc e e

Electrical signal was formed based on the measured gXP85022 characteristics combining with the Geant4 simulation outputs: optical photon’s position and arrival time at photocathode.F h i di id l h t l t th d i lFor each individual photo electron, the measured single photo electron response was assigned. Convolute pulses due to all the photo-electron within the area of TL strip.TL signal then propagates to both ends of TLTL signal then propagates to both ends of TL. In the forward MCP, 24 TL strips run vertically. By applying Anger logic to measured TL signals, X coordinate can be obtainedobtained.TLs runs horizontally in the backward MCP to get Y coordinate in the same way.The position also can be measured from the measured

10

The position also can be measured from the measured time difference at both ends of TL.

Photonis Planacon MCP-PMT (XP85022)Photonis Planacon MCP PMT (XP85022)

Wavelength (nm)200 300 400 500 600 700

Eff

icie

ncy

(%)

0

5

10

15

20

25

30

(a) Quantum Efficiency

Wavelength (nm)200 300 400 500 600 700

Eff

icie

ncy

(%)

0

5

10

15

20

25

30

(a)

Wavelength (nm)200 300 400 500 600 700

Eff

icie

ncy

(%)

0

5

10

15

20

25

30

(a)

Wavelength (nm)200 300 400 500 600 700

Eff

icie

ncy

(%)

0

5

10

15

20

25

30

(a)

Window material Borosilicate, Corning 7056 or equivalentPhotocathode BialkaliMultiplier structure MCP chevron (2), 25 μm pore, 40:1 L:D ratioAnode structure 32×32 array 1 1 / 1 6 mm (size /pitch)

11

Anode structure 32×32 array, 1.1 / 1.6 mm (size /pitch)Active area 53×53 mmOpen-area-ratio 80%

Principles of Transmission Line read-outPrinciples of Transmission Line read out

12[Borrowed from Fukun Tang’s slide]

Prototype Transmission Line boardPrototype Transmission Line board

• 32 micro strip Z=50Ω lines• 32 micro-strip Z=50Ω linesWidth = 1.1mmPitch = 1.6mm

• 6 strips have SMA connectors for test read-out

13

• Developed at U. of Chicago EDG.

3 Experimental Tests3. Experimental TestsA. Single photoelectron responses (SER)A. Single photoelectron responses (SER)

Gain measurementAbsolute calibrationPulse shape of single p.e. -> used in simulation to make waveform due to optical optons.

B. Responses to 511 KeV gammaCoincidence setup: MCP/TL + R9800 PMTM k i t di t i l tiMake an intermediate simulation.Calibrate simulation with experiment results by comparing energy and timing.

14

comparing energy and timing.

A. Single Photoelectron Response (SER)A. Single Photoelectron Response (SER)

Light Shielded Box(b)

Photonis XP85022 / TL

LED

Digital

Light Shielded Box(b)

Photonis XP85022 / TL Digital Oscilloscope

Tektronix DP07354

t

HV PulseGenerator

Fluke 415BLecroy 9211

The test set-up was built using a XP85022 MCP and TL board tomeasure the characteristics of the MCP.Block diagram for test set-up using LED.4 TL channels were connected through SMA to the DPO7354

15

4 TL channels were connected through SMA to the DPO7354oscilloscope (Tektronix).3GHz bandwidth, 20GS/S sampling.

Integrated charge of single p.e.Integrated charge of single p.e.

/ ndf 2χ 125.7 / 23

Constant 7.2± 590.1

Mean 0.0007± 0.1181

Sigma 0.00052± 0.03829

Charge(pC)0 0.1 0.2 0.3 0.4 0.5

1

10

210

310

/ ndf 2χ 94.62 / 30


Mean 0.0004± 0.1186

Sigma 0.00037± 0.03996

(a)

Voltage (kV)2.1 2.2 2.3 2.4 2.5

)6G

ain

(x 1

0

1

/ ndf 2χ 33.66 / 3

Constant 0.03317± -6.345

Slope 0.0143± 2.925

/ ndf 2χ 33.66 / 3

Constant 0.03317± -6.345

Slope 0.0143± 2.925

/ ndf 2χ 125.7 / 23


Mean 0.0007± 0.1181

Sigma 0.00052± 0.03829

Charge(pC)0 0.1 0.2 0.3 0.4 0.5

1

10

210

310

/ ndf 2χ 94.62 / 30


Mean 0.0004± 0.1186

Sigma 0.00037± 0.03996

(a)

Voltage (kV)2.1 2.2 2.3 2.4 2.5

)6G

ain

(x 1

0

1

/ ndf 2χ 33.66 / 3

Constant 0.03317± -6.345

Slope 0.0143± 2.925

/ ndf 2χ 33.66 / 3

Constant 0.03317± -6.345

Slope 0.0143± 2.925

/ ndf 2χ 125.7 / 23


Mean 0.0007± 0.1181

Sigma 0.00052± 0.03829

Charge(pC)0 0.1 0.2 0.3 0.4 0.5

1

10

210

310

/ ndf 2χ 94.62 / 30


Mean 0.0004± 0.1186

Sigma 0.00037± 0.03996

(a)

Voltage (kV)2.1 2.2 2.3 2.4 2.5

)6G

ain

(x 1

0

1

/ ndf 2χ 33.66 / 3

Constant 0.03317± -6.345

Slope 0.0143± 2.925

/ ndf 2χ 33.66 / 3

Constant 0.03317± -6.345

Slope 0.0143± 2.925

/ ndf 2χ 125.7 / 23


Mean 0.0007± 0.1181

Sigma 0.00052± 0.03829

Charge(pC)0 0.1 0.2 0.3 0.4 0.5

1

10

210

310

/ ndf 2χ 94.62 / 30


Mean 0.0004± 0.1186

Sigma 0.00037± 0.03996

(a)

Voltage (kV)2.1 2.2 2.3 2.4 2.5

)6G

ain

(x 1

0

1

/ ndf 2χ 33.66 / 3

Constant 0.03317± -6.345

Slope 0.0143± 2.925

/ ndf 2χ 33.66 / 3

Constant 0.03317± -6.345

Slope 0.0143± 2.925

Integrated charge of single p.e XP85022 MCP gain as a function of HV

SER was measured using the pulsed LED as a light source.Charges was measured by integrating waveforms.The SER signal was spread in ~5 TL.

16

g p-> need to increase number of readout channels.The XP85022 gain at HV = -2300V : 1.5 x 106

Pulse shape of single photoelectronp g p

Time (ns)0 2 4 6 8 10

Am

plitu

de (

mV

)

0

1

2

3

(b)Averaged waveform of SER.

Time (ns)0 2 4 6 8 10

Am

plitu

de (

mV

)

0

1

2

3

(b)Averaged waveform of SER.The maximum TL signal only.The rise time of SER was measured ~560ps.

The measured pulse shape of SER was used

Time (ns)0 2 4 6 8 10

Am

plitu

de (

mV

)

0

1

2

3

(b)

The measured pulse shape of SER was usedfor simulating electrical signals of MCP-PMTby applying it to individual optical photons.

Time (ns)0 2 4 6 8 10

Am

plitu

de (

mV

)

0

1

2

3

(b)

17

B Responses to 511 KeV gammaB. Responses to 511 KeV gamma

Light Shielded Box

R9800 PMTHV : -1300V

Digital Oscilloscope

LSO

Digital OscilloscopeTektronix DP07354Na22

LSO

XP85022 MCP/TLHV : -2300V

MCP/TL coupled to 1x1x10mm3 LSO crystal.Hamamatsu R9800PMT with 6.2x6.2x25mm3 LSO for coincidenceUse Na22 for positron source.

18

pWaveform recorded by Tektronix DPO7354 scope

Intermediate simulation setupIntermediate simulation setup

( ” ”) R9800 PMT

19

MCP-PMT(2”x2”)1x1x10mm3 LSO crystal

R9800 PMT6.25x625x25mm3 LSO

Waveform from MCP/TL & R9800 PMTWaveform from MCP/TL & R9800 PMT

Waveform of MCP/TL+LSO. Waveform of R9800 PMT+LSO

W f d d t 20GS/S li

20

Waveforms were recorded at 20GS/S sampling.Waverform of MCP/TL is for the middle TL among 3 TLs.

Energy spectrum of MCP/TLEnergy spectrum of MCP/TL / ndf 2χ 142.9 / 73


Mean 0.04± 43.13

Sigma 0.038± 4.089

Integrated Charge( pC)10 20 30 40 50 60 700

50

100

150

200

250

300

350

/ ndf 2χ 142.9 / 73


Mean 0.04± 43.13

Sigma 0.038± 4.089

(a)

Entries 19999Mean 25.17RMS 14.51Integral 5204

/ ndf 2χ 252.3 / 24Constant 8.0± 276.4 Mean 0.06± 41.67 Sigma 0.051± 2.827

Integrated Charge (pC)10 20 30 40 50 60 700

50

100

150

200

250

300

/ ndf 2χ 23.01 / 17


Mean 0.07± 43.11

Sigma 0.051± 2.906

/ ndf 2χ 23.01 / 17


Mean 0.07± 43.11

Sigma 0.051± 2.906

(b)

/ ndf 2χ 142.9 / 73


Mean 0.04± 43.13

Sigma 0.038± 4.089


50

100

150

200

250

300

350

/ ndf 2χ 142.9 / 73


Mean 0.04± 43.13

Sigma 0.038± 4.089

(a)




50

100

150

200

250

300

/ ndf 2χ 23.01 / 17


Mean 0.07± 43.11

Sigma 0.051± 2.906

/ ndf 2χ 23.01 / 17


Mean 0.07± 43.11

Sigma 0.051± 2.906

(b)

Real Test22.3% fwhm

Simulation15.8% fwhm

/ ndf 2χ 142.9 / 73


Mean 0.04± 43.13

Sigma 0.038± 4.089


50

100

150

200

250

300

350

/ ndf 2χ 142.9 / 73


Mean 0.04± 43.13

Sigma 0.038± 4.089

(a)




50

100

150

200

250

300

/ ndf 2χ 23.01 / 17


Mean 0.07± 43.11

Sigma 0.051± 2.906

/ ndf 2χ 23.01 / 17


Mean 0.07± 43.11

Sigma 0.051± 2.906

(b)

/ ndf 2χ 142.9 / 73


Mean 0.04± 43.13

Sigma 0.038± 4.089


50

100

150

200

250

300

350

/ ndf 2χ 142.9 / 73


Mean 0.04± 43.13

Sigma 0.038± 4.089

(a)




50

100

150

200

250

300

/ ndf 2χ 23.01 / 17


Mean 0.07± 43.11

Sigma 0.051± 2.906

/ ndf 2χ 23.01 / 17


Mean 0.07± 43.11

Sigma 0.051± 2.906

(b)

Charge sum of 3 TL signal : only left side of TLCharge sum of 3 TL signal : only left side of TL.Compton + 511keV peak structure is clearly found.Discrepancy between the real test and simulation.

E resolution : 22.3% vs 15.8% ( at 511keV peak)

21

E resolution : 22.3% vs 15.8% ( at 511keV peak)Shape of compton continuum.Due to simplified simulation setup( gamma direction).

Coincidence timing:real test vs simulationreal test vs. simulation

/ ndf 2χ 252.7 / 19


Mean 0.002± 8.549

Sigma 0.0013± 0.1769

Time (ns)7 7.5 8 8.5 9 9.5 100

100

200

300

400

500

600

700

800

900

/ ndf 2χ 252.7 / 19


Mean 0.002± 8.549

Sigma 0.0013± 0.1769

(a)



Time (ns)-0.5 0 0.5 1 1.5 20

10

20

30

40

50

60

70

80

90

/ ndf 2χ 71.1 / 31


Mean 0.0061± 0.6277

Sigma 0.0048± 0.1693

/ ndf 2χ 71.1 / 31


Mean 0.0061± 0.6277

Sigma 0.0048± 0.1693

(b)

/ ndf 2χ 252.7 / 19


Mean 0.002± 8.549

Sigma 0.0013± 0.1769

Time (ns)7 7.5 8 8.5 9 9.5 100

100

200

300

400

500

600

700

800

900

/ ndf 2χ 252.7 / 19


Mean 0.002± 8.549

Sigma 0.0013± 0.1769

(a)



Time (ns)-0.5 0 0.5 1 1.5 20

10

20

30

40

50

60

70

80

90

/ ndf 2χ 71.1 / 31


Mean 0.0061± 0.6277

Sigma 0.0048± 0.1693

/ ndf 2χ 71.1 / 31


Mean 0.0061± 0.6277

Sigma 0.0048± 0.1693

(b)

Real Test Simulation~398ps

/ ndf 2χ 252.7 / 19


Mean 0.002± 8.549

Sigma 0.0013± 0.1769

Time (ns)7 7.5 8 8.5 9 9.5 100

100

200

300

400

500

600

700

800

900

/ ndf 2χ 252.7 / 19


Mean 0.002± 8.549

Sigma 0.0013± 0.1769

(a)



Time (ns)-0.5 0 0.5 1 1.5 20

10

20

30

40

50

60

70

80

90

/ ndf 2χ 71.1 / 31


Mean 0.0061± 0.6277

Sigma 0.0048± 0.1693

/ ndf 2χ 71.1 / 31


Mean 0.0061± 0.6277

Sigma 0.0048± 0.1693

(b)

~416ps ~398ps

/ ndf 2χ 252.7 / 19


Mean 0.002± 8.549

Sigma 0.0013± 0.1769

Time (ns)7 7.5 8 8.5 9 9.5 100

100

200

300

400

500

600

700

800

900

/ ndf 2χ 252.7 / 19


Mean 0.002± 8.549

Sigma 0.0013± 0.1769

(a)



Time (ns)-0.5 0 0.5 1 1.5 20

10

20

30

40

50

60

70

80

90

/ ndf 2χ 71.1 / 31


Mean 0.0061± 0.6277

Sigma 0.0048± 0.1693

/ ndf 2χ 71.1 / 31


Mean 0.0061± 0.6277

Sigma 0.0048± 0.1693

(b)

Event selection requirement for the coincidence timingEvent selection requirement for the coincidence timing. R9800PMT : 400 < E < 600 keVMCP 3TL Sum : 35 < Int. Charge < 60pC Leading Edge threshold : 3mV (MCP/TL) 50mV (R9800 PMT)

22

Leading Edge threshold : 3mV (MCP/TL) 50mV (R9800 PMT)Coincidence timing resolution = ~416ps( FWHM) contribution from R9800PMT side = ~200ps (FWHM)

4 Results : Design Simulation4. Results : Design Simulation

Back MCP/TL Front MCP/TLBack MCP/TL Front MCP/TL

23LSO scintillator array

Coincidence Energy & Timing : SimulationCoincidence Energy & Timing : Simulation

Sum of 5 TL signals around the maximum amplitude.Energy resolution : ~11%Energy resolution : 11%Use the measured XP85022 SER for the TL signal.The event time was extracted by Leading Edge (LE) to the maximum TL signal. ( Threshold : 3mV) Energy window [450, 600] KeV required for coincidence

Time (ns)-1.5 -1 -0.5 0 0.5 1 1.50

100

200

300

400

500

600

/ ndf 2χ 40.2 / 19


Mean 0.0022054± -0.0004659

Sigma 0.0017± 0.1376

Entries 9999

Mean 300.5

RMS 170.3

Integral 9999

Energy (keV)0 100 200 300 400 500 600 700 800

1

10

210

310

/ ndf 2χ 119.8 / 59


Mean 0.3± 510.9

Sigma 0.25± 24.06

Energy window [450, 600] KeV required for coincidence event.The detection efficiency : ~40%( ~63% for one module).Coincidence timing resolution : ~323 ps.

Time (ns)-1.5 -1 -0.5 0 0.5 1 1.50

100

200

300

400

500

600

/ ndf 2χ 40.2 / 19


Mean 0.0022054± -0.0004659

Sigma 0.0017± 0.1376

Entries 9999

Mean 300.5

RMS 170.3

Integral 9999

Energy (keV)0 100 200 300 400 500 600 700 800

1

10

210

310

/ ndf 2χ 119.8 / 59


Mean 0.3± 510.9

Sigma 0.25± 24.06

Time (ns)-1.5 -1 -0.5 0 0.5 1 1.50

100

200

300

400

500

600

/ ndf 2χ 40.2 / 19


Mean 0.0022054± -0.0004659

Sigma 0.0017± 0.1376

Entries 9999

Mean 300.5

RMS 170.3

Integral 9999

Energy (keV)0 100 200 300 400 500 600 700 800

1

10

210

310

/ ndf 2χ 119.8 / 59


Mean 0.3± 510.9

Sigma 0.25± 24.06

24Time (ns)

-1.5 -1 -0.5 0 0.5 1 1.50

100

200

300

400

500

600

/ ndf 2χ 40.2 / 19


Mean 0.0022054± -0.0004659

Sigma 0.0017± 0.1376

Entries 9999

Mean 300.5

RMS 170.3

Integral 9999

Energy (keV)0 100 200 300 400 500 600 700 800

1

10

210

310

/ ndf 2χ 119.8 / 59


Mean 0.3± 510.9

Sigma 0.25± 24.06

Energy spectrum of coincidence event Coincidence timing distribution

Position determinationPosition determinationEntries 6256

Mean 2.139

RMS 2.643

Integral 6256

mm-8 -6 -4 -2 0 2 4 6 8 10 120

500

1000

1500

2000

2500

3000

3500

4000Mean 2.236

RMS 1.975

Integral 6157(a)

Mean 2.236

RMS 1.975

Integral 6157

Entries 6256

Mean 2.158

RMS 3.003

Integral 6256

mm-8 -6 -4 -2 0 2 4 6 8 10 120

200

400

600

800

1000

1200

Mean 2.172

RMS 2.502

Integral 6164

(b)

Mean 2.172

RMS 2.502

Integral 6164

Entries 6256

Mean 2.139

RMS 2.643

Integral 6256

mm-8 -6 -4 -2 0 2 4 6 8 10 120

500

1000

1500

2000

2500

3000

3500

4000Mean 2.236

RMS 1.975

Integral 6157(a)

Mean 2.236

RMS 1.975

Integral 6157

Entries 6256

Mean 2.158

RMS 3.003

Integral 6256

mm-8 -6 -4 -2 0 2 4 6 8 10 120

200

400

600

800

1000

1200

Mean 2.172

RMS 2.502

Integral 6164

(b)

Mean 2.172

RMS 2.502

Integral 6164

Entries 6256

Mean 2.139

RMS 2.643

Integral 6256

mm-8 -6 -4 -2 0 2 4 6 8 10 120

500

1000

1500

2000

2500

3000

3500

4000Mean 2.236

RMS 1.975

Integral 6157(a)

Mean 2.236

RMS 1.975

Integral 6157

Entries 6256

Mean 2.158

RMS 3.003

Integral 6256

mm-8 -6 -4 -2 0 2 4 6 8 10 120

200

400

600

800

1000

1200

Mean 2.172

RMS 2.502

Integral 6164

(b)

Mean 2.172

RMS 2.502

Integral 6164

Entries 6256

Mean 2.139

RMS 2.643

Integral 6256

mm-8 -6 -4 -2 0 2 4 6 8 10 120

500

1000

1500

2000

2500

3000

3500

4000Mean 2.236

RMS 1.975

Integral 6157(a)

Mean 2.236

RMS 1.975

Integral 6157

Entries 6256

Mean 2.158

RMS 3.003

Integral 6256

mm-8 -6 -4 -2 0 2 4 6 8 10 120

200

400

600

800

1000

1200

Mean 2.172

RMS 2.502

Integral 6164

(b)

Mean 2.172

RMS 2.502

Integral 6164

d h f l ( 2 2 2 2 )

Reconstructed X using the centroid Recontructed Y using timing difference

511 KeV gamma injected on the center of a crystal (x=2.125, y=2.125)Two ways of position determination.•Energy weighted using 5 TLs (Centroid) (left)•Time difference of the maximum TL at both left/right ends (right)

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•Time difference of the maximum TL at both left/right ends. (right)-> gives the coordinate othogonal direction to the centroid method.

•Position resolution : ~2.5mm of FWHM in both method.

Energy asymmetry and timing difference between back and forward: for DOIbetween back and forward: for DOI

511keV gamma injected from side of detector with 1mm step along Z iaxis.

Energy asymmetry and time difference of front and back due to different interaction depth.

(EFront – EBack)/(EFront + EBack)

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o t ac o t ac

Clear correlations were found.

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mm0 5 10 15 20 25

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Energy asymmetry as a function of depth

Time difference as a function of depth

5 Summary & Plans5. Summary & PlansA PET detector design using pixelated array of LSOA PET detector design using pixelated array of LSO scintillator and MCP PMT with Transmission Line readout was studied.Geant4 was used for optical photon simulation.Geant4 was used for optical photon simulation.Real test setup using XP85022 MCP and TL board was built to measure SER of MCP. The measurement from the test set-up was fed to the simulation for TL signal forming.p g gThe preliminary results from the study show promising results.

Energy resolution~11% at 511keV was obtainedEnergy resolution 11% at 511keV was obtained.The coincidence time resolution ~323ps with ~40% detection efficiency were estimated.Readout at both ends of scintillator makes it possible to

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Readout at both ends of scintillator makes it possible to extract the DOI information.

Summary & Plans - continuedSummary & Plans - continuedA prototype detector module is planned. p yp pMCP-PMT + Transmission Line + Waveform sampling

1. Increase the read-out channels (4 -> 32) would allow more precise measurement.continuous X-tal ( >1cm) can be investigated.uniformity can be studied as well.

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Summary & Plans - continuedSummary & Plans - continued2. Readout electronics.

4 h l di i l ill 62 h l VME b d i4 channel digital oscilloscope -> 62 channel VME board using DRS4 sampling chips.

A prototype( using DRS4 chips at 5GS/s sampling) was developed at EDG of U. of Chicago. (under test)de e oped at G o U o C cago (u de test)

(CAEN will produce 32 channel VME board using DRS4).

ARS16 board(Analog Ring Sampler)

DRS4 evaluation board

( g g p )VME interface16 ch. 1 GS samplingLPC Clemont, France

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USB interface 4 ch. 5 GS samplingPSI, Switzerland

AcknowledgementAcknowledgementCollaboratorsC-T.Chen, C-M.Kao, H.Kim ( Radiology, U. of Chicago)H.Frisch, J-F.Genat, F.Tang, (EFI, U. of Chicago)W.Moses, W.Choong (Lawrence Berkeley Nat. Lab.)

l h kSpecial Thanks to Greg Sellberg at Fermilab for soldering MCP/TLMark Zaskowski at EDG of U of Chicago for technical helpMark Zaskowski at EDG of U. of Chicago for technical help.

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a design of a pet detector using micro-channel plate pmt ... · hamamatsu r9800pmt with...

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