maeo-apds-using-in-scintillation-counter

1、Improvement in scintillation counter energy resolution with the silicon drift detector,*Shuji Maeo1,2, Takayuki Yanagida1, Yuui Yokota1 and Akira Yoshikawa1,3,1Division of Physical Process Design,　Institute of Multidisc

2、iplinary Research for Advanced Materials (IMRAM),　Tohoku University2Japan Association for the Advancement of Medical Equipment3New Industry Creation Hatchery Center(NICHe), Tohoku University,Introduction,High energy r

3、adiation measurementsScintillation counter is useful.,,,,,,Radiation,Scintillator,Light detector,To processor…,Typical detector is Photo Multiplier Tube(PMT).Problems　Energy resolution is not enough.　It c

4、an not use in magnetic fields.,Going to semiconductor,Light,Electrical signal,,,?In Conventional photo diode(PD), signal intensity is low, noise level is high(low S/N ratio).?In Avalanche PD(APD), S/N ratio is not so hi

5、gh.,Scope of research,Improvement of S/N ratio in Scintillation counterUsing an Silicon drift detector (SDD) as light detector,Estimations using the SDDProblems and Next plan,High energy resolution↓Applying PD array

6、etc.↓High contrast imaging,,In this report,Comparison with each light detector,Characteristics of the SDD,,Electron can be collected efficiently for electric field formed by ring like cathode.Anode capacitance is low

7、for small anode size..Field Effect Transistor(FET) can be constructed at SDD directly.Thermal noise can be reduced for cooling by the peltier cooler.High energy resolution and high count rate are available.,Structure

8、of the SDD,P. Lechner et al., Nucl. Instrum. Methods, vol. A-377, 346 (1996).,Affects of energy resolution,Simulation results of peak shape depended on each resolution.,Comparison of X-ray response,FWHM：1.7 keV(2.9%),Np

9、-Lα13.9 keV,Np-Lβ17.7 keV,Np-Lγ20.8 keV,γ26.4 keV,γ59.5 keV,Spectrum of 241Am measured by conventional Si-pin PD,Spectrum of 241Am measured by the SDD,Np-Lα13.9 keV,Np-Lβ17.7 keV,Np-Lγ20.8 keV,γ26.4 keV,γ59.5 k

10、eV,FWHM：0.8 keV(1.3%),,,Hamamatsu (S1722-02),KETEK,Linearity of the pulse heightfor X-rays,Calibration curve,It can be estimated that linearity between pulse height and energy.,,Linearity of the pulse heightfor visibl

11、e light,It can be estimated that linearity between pulse height and luminosity.,,,Advantage of using the SDD,High energy resolution,High energy radiation spectrometry,Imaging,Qualitative analysisAccuratelyQuantitative

12、analysisSensitive,ImageHigh ContrastMeas. timebecome Short,Assemble the scintillator,,,,,,,,,,Scintillator,Effective area of SDD (7 mm2),Peltier cooler,,Coupling by optical grease,Pre AMP(OursTex Co. Ltd.),Shaping A

13、MP(CleaPulse; 4417),Multi channel analyzer(Amptek; MCA8000A),,,,,Scheme of output signal,SDD(KETEK GmbH),,Measurement of scintillation light,,661.7 keV,Back scatter peak,661.7 keV,FWHM : 66.5 keV(10%),FWHM : 79.5 keV(

14、12%),g-ray response of the CsI(Tl) with the conventional Si-pin PD,g-ray response of the CsI(Tl) with the SDD,Scintillator：CsI(Tl)RI source：137CsShaping time：0.5 µsec.Meas. time：1000 sec.,Short wavelength measur

15、ement,g-ray response of the CsI(Tl) with the SDD.,g-ray response of the GSO(Gd2SiO5:Ce) with the SDD.,RI source:137CsShaping time:0.5 msec.Meas.time:1000 sec.,RI source:137CsShaping time:0.5 msec.Meas.time:1000 sec.,

16、Cause of high noise level,From these results, the humidity and air dusts had a big impact for large leakage current.,,,photodiode,package,,,,,,,Normal Si-PD,Package opened,Grease coated,Comparison with capacitance of Si

17、-PD under some conditions,From these results, the capacitance was not effected in surface condition of the detector.,,Signal processing,Analog signal processing,Digital signal processing,,,,,,,High count rateLow noise l

18、evel,,Pre AMP,AD converter,,Pulse height,Scheme of output signal,Scheme of output signal,Shaping AMP,Multi channel analyzer,,,,Pulse height,event No.,Pre AMP,,,,Pulse height,event No.,Summary,The SDD system was applied t

19、o scintillation light detector.High energy resolution (compared with conventional PD) and good linearity were demonstrated.Scintillation light response was achieved. However noise level should be decrease.,Next plan,R