The service provided by the GC(Gamma Cameras)in the Nuclear Medicine departments fails because of their breakdown,generally due to the associated electronics and not to the physical detection components.For this reaso...The service provided by the GC(Gamma Cameras)in the Nuclear Medicine departments fails because of their breakdown,generally due to the associated electronics and not to the physical detection components.For this reason,it was decided to develop an electronic system that allows the recovery and optimization of disused GC,starting with the design of the preamplifier for a PMT(photomultiplier tube).The circuit was designed and simulated and the list of components necessary for the construction of the preamplifier was generated,as well as the printed circuit board was designed for its assembly.By simulating the preamplifier this worked in linear mode.This determines that the amplitude of the output signal is proportional to the amount of charge delivered by the detector.This card allows an automatic adjustment of the signals of the PMT as do the modern GC.展开更多
Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been devel...Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been developed at the Institute of Modern Physics,Chinese Academy of Sciences.The two-dimensional photocathode position scanning capability is an intrinsic function of the test bench,and up to 25 PMTs,with the diameter smaller than 2",can be tested simultaneously.The parameters of the light source pulses can be adjusted in a wide range,thus making it suitable for various characteristics measurements.The test bench system is highly automated with all the controlling operations integrated into a single software.Additionally,the hardware platform is extensible which allows complex testing schemes,and the modularity in the software design makes the migration from one testing configuration to another light-weight and efficient.All these features make the test bench versatile and reusable in different experiments.It has been first used in the construction of the Plastic Scintillator Detector(PSD) of DArk Matter Particle Explorer(DAMPE),and a total of 570 Hamamatsu R4443 tubes were tested successfully.The performance was verified and the testing results are also reported in this article.展开更多
The performance of gamma camera with NaI(Tl) array coupled with position sensitive photomultiplier tube (PSPMT) R2486 has been studied. The pixel size of NaI(Tl) crystal is 2mm×2mm and the overall dimension of th...The performance of gamma camera with NaI(Tl) array coupled with position sensitive photomultiplier tube (PSPMT) R2486 has been studied. The pixel size of NaI(Tl) crystal is 2mm×2mm and the overall dimension of the array is 48.2mm×48.2mm×5mm. There are 484 pixels in a 22×22 matrix. Because each pixel can produce a much focused light spot and restrict the spread of photons, position resolution of the gamma camera is mainly determined by pixel size. It is shown that crystal array pixel can reduce shrinkage effect and improve intrinsic position resolution greatly via restricting the spread of photons. Experimental results demonstrate that its position resolution and linearity are much improved comparing with the gamma camera using planar crystals coupled with PSPMT.展开更多
With the technology of coincidence method, transit time spreads (TTSs) of PMTs are measured with Cherenkov light on the photocathode window of photomultiplier tube (PMT) produced by cascade γ radiation source, 60Co. ...With the technology of coincidence method, transit time spreads (TTSs) of PMTs are measured with Cherenkov light on the photocathode window of photomultiplier tube (PMT) produced by cascade γ radiation source, 60Co. TTSs with single and multi-photoelectron which are analyzed by convolution of Poisson and Gaussian are obtained. The study to XP2020 and XP2020Q PMTs shows that TTSs are consistent with data supplied by Philips. TTSs are inversely proportional to the square roots of number of photoelectrons. The method is feasible when single and multi-photoelectron can be distinguished.展开更多
Hamamatsu R1924A is one of the most widely used photomultiplier tubes(PMTs) in nuclear physics.Since the active base suitable for R1924A is still not available in market, an active base is designed for Hamamatsu R1924...Hamamatsu R1924A is one of the most widely used photomultiplier tubes(PMTs) in nuclear physics.Since the active base suitable for R1924A is still not available in market, an active base is designed for Hamamatsu R1924A PMT, and the test results at high counting rates are presented. The active bases with two different sets of resistor chains were tested and compared by a frequency-controlled green straw hat LED light. A stable signal output up to 100 kHz is achieved using frequency-controlled LED pulsed light. The temperature of bases, which reflects the power consumption and is crucial for applications in vacuum, is also monitored with the same LED pulsed light. The temperature of the active base with smaller resistances reaches about twice of that of the active base with larger resistances in the resistor chain. For the applications in vacuum, the active base with resistance between the two sets of resistor chains may be preferable.展开更多
文摘The service provided by the GC(Gamma Cameras)in the Nuclear Medicine departments fails because of their breakdown,generally due to the associated electronics and not to the physical detection components.For this reason,it was decided to develop an electronic system that allows the recovery and optimization of disused GC,starting with the design of the preamplifier for a PMT(photomultiplier tube).The circuit was designed and simulated and the list of components necessary for the construction of the preamplifier was generated,as well as the printed circuit board was designed for its assembly.By simulating the preamplifier this worked in linear mode.This determines that the amplitude of the output signal is proportional to the amount of charge delivered by the detector.This card allows an automatic adjustment of the signals of the PMT as do the modern GC.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Science(No.XDA04040202-3)
文摘Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been developed at the Institute of Modern Physics,Chinese Academy of Sciences.The two-dimensional photocathode position scanning capability is an intrinsic function of the test bench,and up to 25 PMTs,with the diameter smaller than 2",can be tested simultaneously.The parameters of the light source pulses can be adjusted in a wide range,thus making it suitable for various characteristics measurements.The test bench system is highly automated with all the controlling operations integrated into a single software.Additionally,the hardware platform is extensible which allows complex testing schemes,and the modularity in the software design makes the migration from one testing configuration to another light-weight and efficient.All these features make the test bench versatile and reusable in different experiments.It has been first used in the construction of the Plastic Scintillator Detector(PSD) of DArk Matter Particle Explorer(DAMPE),and a total of 570 Hamamatsu R4443 tubes were tested successfully.The performance was verified and the testing results are also reported in this article.
基金Supported by National Foundation of Natural Sciences of China (10275063)
文摘The performance of gamma camera with NaI(Tl) array coupled with position sensitive photomultiplier tube (PSPMT) R2486 has been studied. The pixel size of NaI(Tl) crystal is 2mm×2mm and the overall dimension of the array is 48.2mm×48.2mm×5mm. There are 484 pixels in a 22×22 matrix. Because each pixel can produce a much focused light spot and restrict the spread of photons, position resolution of the gamma camera is mainly determined by pixel size. It is shown that crystal array pixel can reduce shrinkage effect and improve intrinsic position resolution greatly via restricting the spread of photons. Experimental results demonstrate that its position resolution and linearity are much improved comparing with the gamma camera using planar crystals coupled with PSPMT.
文摘With the technology of coincidence method, transit time spreads (TTSs) of PMTs are measured with Cherenkov light on the photocathode window of photomultiplier tube (PMT) produced by cascade γ radiation source, 60Co. TTSs with single and multi-photoelectron which are analyzed by convolution of Poisson and Gaussian are obtained. The study to XP2020 and XP2020Q PMTs shows that TTSs are consistent with data supplied by Philips. TTSs are inversely proportional to the square roots of number of photoelectrons. The method is feasible when single and multi-photoelectron can be distinguished.
基金supported by the National Natural Science Foundation of China(Nos.91426301 and 11075189)the Strategic Priority Research Program of the Chinese Academy of Sciences"ADS project"(No.XDA03030200)+2 种基金the Program for the CAS"Light of West China"(No.29Y601030)the US Department of Energy(No.DE-FG02-93ER40773)the program of the"visiting professorship of senior international scientists of the Chinese Academy of Sciences"for their support during his stay at the IMP
文摘Hamamatsu R1924A is one of the most widely used photomultiplier tubes(PMTs) in nuclear physics.Since the active base suitable for R1924A is still not available in market, an active base is designed for Hamamatsu R1924A PMT, and the test results at high counting rates are presented. The active bases with two different sets of resistor chains were tested and compared by a frequency-controlled green straw hat LED light. A stable signal output up to 100 kHz is achieved using frequency-controlled LED pulsed light. The temperature of bases, which reflects the power consumption and is crucial for applications in vacuum, is also monitored with the same LED pulsed light. The temperature of the active base with smaller resistances reaches about twice of that of the active base with larger resistances in the resistor chain. For the applications in vacuum, the active base with resistance between the two sets of resistor chains may be preferable.
基金supported by Gansu Province Higher Education Industry Support Plan Project(No.2023CYZC-40)Lanzhou Science and Technology Development Plan Project(No.2023-3-104)。
