michiaki takahashi n. higashi, s. iwaki, s. kabuki, h. kubo, s. kurosawa,
DESCRIPTION
Development of an Electron-Tracking Compton Camera using CF 4 gas at high pressure for improved detection efficiency. Michiaki Takahashi N. Higashi, S. Iwaki, S. Kabuki, H. Kubo, S. Kurosawa, K. Miuchi, K. Nakamura, J. D. Parker, T. Sawano, A. Takada A , T. Tanimori, K. Taniue, and K. Ueno. - PowerPoint PPT PresentationTRANSCRIPT
Development of anElectron-Tracking Compton Camera
using CF4 gas at high pressurefor improved detection efficiency
Michiaki TakahashiN. Higashi, S. Iwaki, S. Kabuki, H. Kubo, S. Kurosawa,
K. Miuchi, K. Nakamura, J. D. Parker, T. Sawano, A. TakadaA, T. Tanimori, K. Taniue, and K. Ueno
Dept. of Physics, Graduate school of Science, Kyoto University, Kyoto, Japan
AISAS/JAXA, Kanagawa, JapanThe Twelfth Vienna Conference on Instrumentation, Vienna, Austria
20 February 2010
Outline
・ Introduction Electron-Tracking Compton Camera (ETCC) Medical imaging / MeV gamma-ray astronomy・ Optimization of gas mixture・ Operation at high pressure・ Summary
Electron-Tracking Compton Camera (ETCC)
μTPC (Time Projection Chamber )--- 3D track and energy of Compton-recoil electron Scintillation camera--- position and energy of scattered gamma ray
Scintillator
μPICGEM
e-
B26 K. Ueno, A22 S. Kurosawa
2 events1 2 3
5 10 100
Determination of direction and energy of each incident gamma ray Large FOV ( 3 sr)
10 cm
400 m pitch
anodecathode
Proton
10cm
Electron
Example of 3D track
Electricfield
TPC (Time Projection Chamber)for 3D electron track
GEM (Gas Electron Multiplier) (F. Sauli (1997))+ μPIC (micro PIxel Chamber) 2D readout micro pattern gaseous detector 2D readout + Drift time 3D track
Prototype TPC size : 10×10×10 cm3
Gas : Ar/C2H6 (90:10) at 1 atm, sealedPosition resolution : 150 m (1D)Stable gas gain : 30000 (PIC : 3000, GEM : 10)
GSO and LaBr3 Scintillation Cameras
GSO 8×8 Pixel 13 mm 6 mm
15 x 15 cm2 Camera(GSO or LaBr3 + Multi anode PMT (H8500, HPK))
• Number of pixels: 576• Pixel size 6×6×13 mm3 (GSO) 6×6×15 or 20 mm3 (LaBr3)• GSO Energy resolution :10.0 % (@662keV, FWHM)• LaBr3 Energy resolution: 6.5% (@662keV, FWHM)• Position resolution: 6mm
Black :GSORed : LaBr3
15 cm
5 cm
MeV gamma-ray camera projects
Astronomy : Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment (SMILE)
1. SMILE-I (2006, launched)• Operation test of ETCC @35 km• Measurement of diffuse cosmic and atmospheric gamma rays ( 400 photons) 4 hours
2. SMILE-II (2011)• Observation of Crab Nebula or Cygnus X-1 3 hours
Medical : Advantage point: wide energy dynamic range (300 – 3000 keV) and wide FOV (SPECT < 300 keV, PET 511 keV) 1. Multi RI Tracer Imaging --- The development of new RI drugs 2. Proton Therapy --- Real time monitor of prompt gamma rays to measure Bragg-peak position
Scinti : LaBr3
Scinti : GSO
Energy window : ±10% 1004 1228 keV
Examples of Medical ImagingZn-65-Porphyrin imaging (1116 keV) Porphyrin was accumulated in RGK-36 which is the tumor of rat stomach cancer.
γ
60cm
180cm
365 keV(Tumor)
511keV(Brown fat cell)
Scinti : LaBr3
2 sources imaging
ETCC for medical use
Activity : 0.16 MBqTime : 110.5 hoursEvents : 173 events
Scintillator
TPC
Time : 6 hours
ETCC/CT
ETCC/CTSpatial resolution 10 mm (FWHM)
Improvement of detection efficiency
• Optimization of gas• Operation at high pressure
Increase detection area• Multi-head camera (10×10×10 cm3×2,3,…) • Developing a large size ETCC (30×30×30 cm3)
For High Sensitivity
2 times better thanour prototypes
Demerit of CF 4 gas Low gas gain isoC4H10 gas (penning effect)
High dependence of drift velocity on electric field worse
position resolution ?
Selection of gas sealed in TPC
Merit of CF 4 gas
Small diffusion better position resolution (for TPC) better angular resolution (for ETCC) low Z (C : Z=6, F : Z=9) and 42 electrons in one molecule Compton scattering is dominant higher efficiency (for ETCC)
Ar/C2H6 (90:10) CF4 gas mixture
Drift CageDrift Cage
10 cm10 cm 10 cm
Optimize the gas mixture
Electronics
TPC
source
GEM (SciEnergy)
PIC
Gas Ar/C2H6 (90:10) Ar CF4
isoC4H10
Measurement1.Gas Gain2.Position Resolution
Requirements : High CF4 ratio
Gas Gain 20,000
10 cm
CF4 45%
CF4 50%
Improved by more than 2by introducing isoC4H10
This gasThis gas
GEM = 340V The other GEM = 400V
CF4 20%CF4 30% CF4 40%
Gas Gain at 1 atm Penning effect of isoC4H10
= 162 m
D = 81 m/cm1/2
= 162 m
D = 81 m/cm1/2
Ar/CF4/isoC4H10 (54:40:6)
muon tracks
= 156 m
D = 175 m/cm1/2
= 156 m
D = 175 m/cm1/2
Better by factor 2
22detector
2 )()( lDl l : Drift lengthD : Diffusion Constantl : Drift lengthD : Diffusion Constant
Position Resolution
Ar/C2H6 (90:10))
2( detector
Ar/C2H6 (90:10) at 1 atm
Ar/C2H6 (90:10) at 2 atm
Ar/CF4/isoC4H10 (54:40:6) at 1 atm
Ar/CF4/isoC4H10 (54:40:6) at 1.4 atm
Measurement1.Gas Gain2.Drift Velocity3.Position Resolution4.Energy Resolution
High Pressure100 mm
2 mm
100 mt GEM
2 mm
100 mm 50 mt GEMPIC
Drift Plane (Al Mylar)
Electronics
TPC
source
Gas Gain
Upper GEM = 350VLower GEM = 250V
Upper GEM = 460VLower GEM = 360V
Upper GEM = 500VLower GEM = 380V
Upper GEM = 610VLower GEM = 450V
Lower gas gain
Drift Velocity
Difference betweensimulation andmeasurementis smaller than 10%
Position Resolution
Ar/C2H6 (90:10)at 1 atm
Ar/C2H6 (90:10)at 2 atm
Ar/CF4/isoC4H10 (54:40:6)at 1 atm
Ar/CF4/isoC4H10 (54:40:6) at 1.4 atm
= 332 m, D = 246 m/cm1/2 = 302 m, D = 204 m/cm1/2
= 378 m, D = 147 m/cm1/2 = 330 m, D = 128 m/cm1/2
Better by factor 2Better by factor 1.6
Energy Resolution31 keV X-ray from 133Ba (31 keV)
Ar/C2H6 (90:10) at 1 atm Ar/C2H6 (90:10) at 2 atm
Ar/CF4/isoC4H10 (54:40:6) at 1 atm Ar/CF4/isoC4H10 (54:40:6) at 1.4 atm
43.8% (FWHM) @31 keV 53.1% (FWHM) @31 keV
56.1% (FWHM) @31 keV 60.0% (FWHM) @31 keV
Worse than prototype
Imaging with ETCCgamma-ray from 133Ba (356 keV, 800 kBq)
Electronics
TPC
sourceGSO Scintillation Camera
Measurement1. Efficiency2. Angular resolution (ARM
and SPD)
15 cm
ARM : Angular Resolution MeasureSPD : Scatter Plane Deviation
Efficiency and Angular Resolution (133Ba 356 keV)Gas Pressure Efficiency ARM (FWHM) SPD (FWHM)
Ar/C2H6 (90:10) 1 atm 1.81×10-5 10.4° 114.8°Ar/C2H6 (90:10) 2 atm 3.55×10-5 11.1° 105.1°
Ar/CF4/isoC4H10 (54:40:6) 1 atm 2.44×10-5 11.7° 117.9°Ar/CF4/isoC4H10 (54:40:6) 1.4 atm 3.51×10-5 11.2° 119.1°
AR
M (
FWH
M)
[degre
e]
10
1
50
5
SMILE-I 2006(Xe + GSO)
Ar/C2H6 TPC + GSO scintillatorthe highest spec.
This Work (GSO)
Ar/CF4/isoC4H10 (54:40:6)at 1.4 atm
Imaging of 133Ba15 cm away from top of
TPC
better byfactor 1.94
Ar/C2H6 TPC+ LaBr3 scintillator
Summary• In order to improve the efficiency of the ETCC, we have
optimized the gas mixture and pressure sealed in the TPC.• The highest ratio of CF4 gas with steady gas gain of 20,000
is Ar/CF4/isoC4H10 (54:40:6).
• The diffusion constant of Ar/CF4/isoC4H10 (54:40:6) is
2 times better than that of Ar/C2H6 (90:10), so the position resolution is improved.
• The efficiency for the ETCC using Ar/CF4/isoC4H10 (54:40:6) at 1.4 atm is 2 times higher than that using Ar/C2H6 (90:10) at 1 atm, and those ARMs are comparable (11 at 356 keV (FWHM)).
Thank youfor your attention
Vs. Conventional Compton Camera Advanced Conventional
•Reconstruction : circle •Direction error region : donut
DO NOT measurethe track of a Recoil electron
150 events
600 events
-15-15
15
15
X [cm]
Y [
cm]
-15-15
15X [cm]
15
Y [
cm]
137Cs(1MBq)2, Classical Compton137Cs(1MBq)2, Advanced Compton
Measure the 3-D track of a Recoil electron
•Reconstruction : point •Direction error region: arc
COMPTELOur ETCC
Position-Sensitive Scintillation Camera
13mm6 mm
5cmMulti-anodePhoto Multiplier Tube (PMT)HPK H8500 8x8 anodes
GSO(Ce) 8x8 pixelsPixel size: 6x6x13mm3
5cm
-0.8 -0.4 0 0.4 0.8 X-position (a. u.)
0.8
0.4
0
-0.4
-0.8
Y-po
sitio
n (a
. u) 500
400
300
200
100
0
Coun
ts (a
. u.)
2-D image in flood-field irradiation
137Cs
Dynamic energy range: 0.08 -1 MeVEng. Resolution: 10.5 % @662 keV
Assembly of LaBr3(Ce) array
6.1 mm pitch
Using our technique, we assembled an 88 array.
54mm
20mm
(=multi-anode PMT H8500 anode pitch)
GSOarray
LaBr3 array
LaBr3 FWHM(%)=
(5.70.4) (E/662keV)-0.530.01
GSO FWHM(%)=
(10.40.3)(E/662keV)-0.510.01LaBr3 : hygroscopic
Hermetic package
GSO monolithicLaBr3 monolithic
133Ba
E/E = 4.1 0.1 % @ 356 keV (FWHM)
Angular Res. Simulation including TPC
Scattered E : energy
Recoil e-
K: energy
Scattering angle φ
Incident φ Angular resolution (ARM)
Calculated assuming1, no error in position of Compton point
2, energy Res. of TPC : 30 % @ 22 keVEng. Res. (FWHM) of LaBr3(Ce) :
~ 3 % @ 662 keV Loef et al. (2001)
Doppler broadening (Ar) Zoglauer et al. (2003)
Ang
ular
res
olut
ion
(FW
HM
) [d
egre
e]
10.5 % 4.27% 3.15% 2.33% 2.1
Sci. Eng. Res. @662keV
ETCC. AngularRes. @662keV(FWHM)
Energy Dynamic Range
Ce-139
Cr- 51
Ba-133
I-131
Au-198
Na- 22
F-18
Cu- 64
Cs-137
Mn-54
Fe- 59
Zn- 65
Co- 60
Energy [keV]
167 320 354 364 412 511, 1275
511 511 662 835 1095, 1292
1116 1173, 1333
Energy dynamic range : 167 – 1333 keV.
Measured sources
SPECT PET
26
Spatial resolution vs. Energy
Goal : Same resolution as human PET @ 511keV
Spatial Resolution
27
I-131-MIBG & F-18-FDG imaging (365 & 511 keV)
PET/SPECT/CT
Rainbow : PETOrange : SPECT
Rainbow : 511keVOrange : 365keV
PC12
Brown fat cell
PC12
Brown fat cell
6cm
Dept. of Bioanalysis, Kyoto UniversityH. Kimura, H. Amano and H. Saji
Scinti : LaBr3
Zn-65 mouse imaging
Measurement after dissectionLiver :0.04 MBqSpleen :0.02Pancreas:0.02Heart :0.02Stomach : 0.01Kidney : 0.00Intestinal:0.11Brain :0.02Other :0.79BG :0.03
Mouse Zn-65 imaging
Energy : 1116keV activity : 1.4MBq obs. time : 2784 min Events : 629 events
3x3 LaBr3 Install to 10cm-ETCC
Zn is a good tracer for diabetes
All kinds of experiment gas (45 types)No
.Gas
1 CF4/isoC4H10 (95:5)
2 CF4/isoC4H10 (90:10)
3 CF4/isoC4H10 (80:20)
4 Ar/C2H6 (90:10)
5 Ar/C2H6/CF4 (72:8:10)
6 Ar/C2H6/CF4/isoC4H10 (69.3:7.7:20:3)
7 Ar/C2H6/CF4 (63:7:30)
8 Ar/C2H6/CF4 (54:6:40)
9 Ar/C2H6/CF4 (45:5:50)
10 Ar/C2H6/CF4/isoC4H10 (42.3:4.7:50:3)
11 Ar/C2H6/CF4 (27:3:70)
12 Ar/CF4/isoC4H10 (95:3:2)
13 Ar/isoC4H10 (90:10)
14 Ar/CF4 (90:10)
15 Ar/CF4 (80:20)
No.
Gas
31 Ar/CF4/isoC4H10 (64:30:6)
32 Ar/CF4/isoC4H10 (63:30:7)
33 Ar/CF4/isoC4H10 (56:40:4)
34 Ar/CF4/isoC4H10 (55:40:5)
35 Ar/CF4/isoC4H10 (54:40:6)
36 Ar/CF4/isoC4H10 (53:40:7)
37 Ar/CF4/isoC4H10 (52:40:8)
38 Ar/CF4/isoC4H10 (49:45:6)
39 Ar/CF4/isoC4H10 (47:50:3)
40 Ar/CF4/isoC4H10 (46:50:4)
41 Ar/CF4/isoC4H10 (45:50:5)
42 Ar/CF4/isoC4H10 (44:50:6)
43 Ar/CF4/isoC4H10 (43:50:7)
44 Ar/CF4/isoC4H10 (42:50:8)
45 Ar/CF4/isoC4H10 (40:50:10)
No.
Gas
16 Ar/CF4/isoC4H10 (78:20:2)
17 Ar/CF4/isoC4H10 (77:20:3)
18 Ar/CF4/isoC4H10 (76:20:4)
19 Ar/CF4/isoC4H10 (75:20:5)
20 Ar/CF4/isoC4H10 (74:20:6)
21 Ar/CF4/isoC4H10 (73:20:7)
22 Ar/CF4/isoC4H10 (72:20:8)
23 Ar/CF4/isoC4H10 (73:25:2)
24 Ar/CF4/isoC4H10 (72:25:3)
25 Ar/CF4/isoC4H10 (71:25:4)
26 Ar/CF4/isoC4H10 (70:25:5)
27 Ar/CF4/isoC4H10 (69:25:6)
28 Ar/CF4/isoC4H10 (67:30:3)
29 Ar/CF4/isoC4H10 (66:30:4)
30 Ar/CF4/isoC4H10 (65:30:5)
CF4 base
Ar/C2H6 (90:10) base
Fixing CF4 ratiochanging Ar and isoC4H10 ratio
-PIC : 2-D gaseous detector
10cm
Size: 10 cm x 10 cmPixel pitch: 400 m ~ 65,000 pixelsGas gain: ~6,000 (stable operation of more than 1 month)
400μm pitch
anode cathode
Cu
-PIC : gain and Energy spectrum
Gas gain uniformityRMS ~ 7%
Energy spectrum (55Fe)
E/E 30% @ 5.9 keV
Ar-escape
0 2 4 6 8 10Energy [keV]
We filled with Ar(90%) + C2H6(10%) gas at 1atm
X-ray imaging with -PIC
Test chart imageTest chart imagePosition resolution:120 m
AMP-Discri. BoardBased on a chip for ATLAS Thin Gap Chamber0.8V/pC
1 mm
Proton Therapy
150MeVproton
200MeV
Depth in Tissue (water) [mm]
Attack on Cancerous cells
proton
Gammarays
neutronWater phantom
Simulation studyETCC :ability to detect Prompt gamma rays as the monitor
Wide energy range (0.1-10 MeV)Rejection of Neutron Wide field of view (~3 str.)
511keV2.2MeV
Gamma raysneutron
Simulation
Monitoring Before treatment:
ionization chamber After treatment:
PET technique (PET: positron emission tomography)
Real time : none
We are developing a monitor for Proton Therapy
160 MeV Proton
Water Phantom
ETCC(10cm)3 TPC
30cm
Experiment in Osaka Univ. Research Center for Nuclear Physics (RCNP)
collaborator :J. Kim(Research Institute and Hospital, National Cancer Center, Korea)
Sensitivity in X / Gamma-ray Astronomy
bad
good
1mCrabEGRET
AirCherenkovFermi
~1 °
suzakuHXD
co
nti
nu
ou
s s
ens
itiv
ity
[e
rg/c
m2/s
ec
]energy [eV]
Our goal
keV GeV TeVMeV
Energy spectrumdiffuse cosmic rays atmospheric rays
SMILE-1
Previous results
10 102 103 104 105
[Energy]
Flu
x [p
hot
ons
/ (c
m2 s
ec
str
keV
)]
10-1
10-3
10-5
10-7
SMILE-1
Previous results
Flu
x [p
hot
ons
/ (c
m2 s
ec
str
keV
(g
/ cm
2))
]
10-2
10-4
10-6
10-8
10 102 103 104 105
[Energy]
We detected 420 photons (Total)@0.15-1 MeV, 32-35 km for 4 hours