Application of CMOS charge-sensitive preamplifier in triple-GEM detector

1 Introduction With novel materials and advanced technique of printed circuit board (PCB) and micro-electronics be- ing used in MPGD, over the past two decades, great progress has been made in MPGD[1], and as a new type of MPGD, the GEM[2] detector was developed during the late 1990s. Standard GEM from CERN is a thin, two-side copper-coated Kapton foil, perforated with a high density of holes etched using a photolitho- graphic process. The diameter of these holes is about 70 μm (ext…     

硅多条探测器性能测试

介绍了对一种由近代物理研究所和北京大学联合研制的硅多条探测器性能测试的结果。具体测试内容包括：探测器的能量分辨率、Al面厚度以及探测器各条间的cross-talk(相互影响)。同时,也对进口的Canberra有确定标称的硅多条探测器做了类似的测试,并进行了性能对比。     

Readout responses of inclined strips in position-sensitivedetectors

Readout responses for the inclined strips in position-sensitive detectors have been studied using theoretical predictions and experimental results. Inclined strips are almost along the displacement direction of incident particles. Rotating conventional strips to near horizontal strips decreases the number of strips by a tangential factor for long-length position sensing. In addition to the channel reduction, the inclined strips modify about 10% in the readout linearity compared to the long-length zigzag patterns. There is resolution degradation because of the inherent high sensitivity of these strips to the avalanche size (about 8% of the detector full length). Double peak responses were observed for sensing the positions of the incident particles. Our theoretical predictions and experimental results are discussed in this paper     

Si-PIN硅条带探测器的电子学测试

采用电子学等效方法对所研制的Si-PIN条带探测器的基本性能进行测试。Si-PIN条带探测器是在—个硅基片上刻蚀多个条带探测器,常用于空间探测中的粒子方向测量。介绍了对Si-PIN条带探测器电子学等效测试方法和结果,重点探讨了条带之间的串扰问题。     

双面硅条探测器的研制与测试

研制了双面硅条探测器。探测器灵敏面积为48mm×48mm,厚约300μm,结面和欧姆面的硅条互相垂直,均由相互平行、宽度相等的48条组成,每条宽0.9mm、间距0.1mm。对其电气特性(耗尽偏压、反向漏电流、条间电阻)和探测特性(上升时间、能量分辨、条间串扰)进行了测试。在偏压为-15V时,各条平均反向漏电流小于10nA。对于从结面入射的5.157 MeV的α粒子,前放信号上升时间约45ns,结面各条的能量分辨率约0.6%~0.7%,基本无条间串扰;欧姆面各条能量分辨率较差,存在条间串扰。     

Submicron position-sensitive detector

A method has been developed to measure precisely the coordinates of charged particles incident between adjacent strips of a strip detector. The position sensitivity of an inter-strip gap has been studied by means of a pulsed laser beam and irradiation by -particles of a ²²⁶Ra-source. The capacitive division of charge generated by the incident particle depends on the position of its track. Its coordinates were determined by two-dimensional amplitude analysis of the charges collected by neighbouring strips. This method of coordinate determination applied to studies of spatial and energy distributions of electromagnetic as well as charged particle beams (including radioactive ion beams) of low intensity could provide the highest level of the precision limited by the track dimensions of charged particles, i.e. percents of a micrometer.     

角度灵敏平行板雪崩探测器及其应用

本文描述了其电极具有等距离分布的同心半圆环状窄条结构的位置灵敏平行板雪崩探测器(ASPD)的结构和工作原理。用此探测器可直接读出入射粒子的散射角θ和方位角φ以及时间信息。在流动的正庚烷气体中(气压950Pa)用~(241)Am α粒子对探测器进行了检验。得到θ方向角度分辨为Δθ=0.286°(对应于阴极平面上的径向位置分辨Δr=1.5mm),φ方向角度分辨Δφ=6°。时间分辨580ps。并给出了在串列静电加速器上被Au 靶弹性散射的α粒子的角分布的实验测量结果。     

The silicon tracker readout electronics of the gamma-ray large area space telescope

A unique electronics system has been built and tested for reading signals from the silicon-strip detectors of the Gamma-ray Large Area Space Telescope mission. The system amplifies and processes signals from 884 736 36-cm strips using only 160 W of power, and it achieves close to 100% detection efficiency with noise occupancy sufficiently low to allow it to self trigger. The design of the readout system is described, and results are presented from ground-based testing of the completed detector system.     

位置灵敏平行板雪崩计数器

一个采用独特的位置读出方法(阴极本身作为读出延迟线)的位置灵敏平行板雪崩计数器已得到初步结果;该探测器工作在1.33—2.67kPa的异丁烷气体中,得到好于1mm的位置分辨和约350ps的时间分辨(对~(252)Cf裂变源)。     

ΔE-E望远镜在~9C碎裂反应上的应用

为研究9 C的晕核结构,一套ΔE-E望远镜探测器应用在兰州放射性次级束流线(RIBLL)上进行的9 C碎裂反应实验中,用来测量反应中产生的碎片。为解决ΔE-E望远镜中硅条的干扰问题及硅条和CsI的能量刻度,利用硅条的感应信号对重离子在硅条上产生的饱和信号进行能量刻度,并通过模拟程序与事例得到的刻度点对CsI(Tl)晶体进行能量刻度。同时使用在硅条和CsI(Tl)晶体上的位置信息对反应物径迹进行重建,从而得到同一离子在硅条与CsI(Tl)晶体上信号的符合,并得到了最终的有效物理事件。     

Self-calibrating position-sensitive silicon detectors

Position-sensitive silicon detectors with discrete position output signal levels, which have been developed for heavy ion reaction studies at the Lawrence Berkeley Laboratory are discussed. The detectors, both 300- and 5000-μm thick, for use in ΔE-E telescopes, use a series of high and low conductivity strips on the detector p⁺ contact to produce a position signal with 15 discrete levels. Since the position of the signals from the strips is known, the detectors are self-calibrating against position nonlinearities. Some aspects of the fabrication of both the 300- and 5000-μm detectors are discussed, along with their operating characteristics. Illustrative experimental results of ¹³⁹La-induced reactions on ⁴⁰Ca targets are presented     

凸度仪X光机参数设置有效性的实验验证

X射线板带材凸度检测系统采用双X射线源和双排充气电离室探测器,对热轧生产线上的钢板进行厚度和凸度等参数的检测,X射线的能量和强度是决定钢板测厚精度的重要因素。为了保证测量精度,本文依据国标GB/T15636—2008假定由统计涨落引入的测厚误差应小于±0.06%,在X光机管电压为180kV、电流为11mA的情况下,从理论上估算了满足以上精度探测器输出的最大相对标准偏差,通过实验对测厚范围内的钢板进行测量,计算出各路探测器输出在不同厚度钢板时的相对标准偏差。实验结果表明,在满足系统测量速度的情况下,通过对几个原始数据进行平均,可使统计涨落小于理论估算值。X光机设置的管电压和管电流参数满足测厚精度的要求。     

Compton scatter and X-ray crosstalk and the use of very thinintercrystal septa in high-resolution PET detectors

To improve spatial resolution, positron emission tomography (PET) systems are being developed with finer detector elements. Unfortunately, using a smaller crystal size increases intercrystal Compton scatter and X-ray escape crosstalk, causing positioning errors that can lead to degradation of image contrast. We investigated the use of extremely thin (<300 μm) lead strips for passive shielding of this intercrystal crosstalk. Using annihilation gamma rays and small (2- and 3-mm wide) bismuth germanate (BGO) crystal detectors in coincidence, crosstalk studies were performed with either two small adjacent crystals [(one-dimensional) (1-D)] or one crystal inside a volume of BGO [(two-dimensional) (2-D)]. The fraction of Compton scattered events from one crystal into an adjacent one was reduced, on average, by a factor of 3.2 (2.2) in the 1-D experiment and by a factor of 3.0 (2.1) in 2-D one, with a 300 (150)-μm-thick lead strip in between the crystals and a 300-700-keV energy window in both crystals. We could not measure a reduction in bismuth X-ray crosstalk with the use of lead septa due to the production of lead X-rays of similar energy. The full-width at half-maximum (FWHM) of the coincident point-spread function (CPSF) was not significantly different for the 1- and 2-D studies, with or without the different septa in place. However, the FWTM was roughly 20% smaller with the 300-μm lead shielding in place. These results indicate that intercrystal crosstalk does not affect the positioning resolution at FWHM, but does affect the tails of the CPSF. Thus, without introducing any additional dead area, an insertion of very thin lead strips can reduce the extent of positioning errors. Reducing the intercrystal crosstalk in a high-resolution PET detector array could potentially improve tomographic image contrast in situations where intercrystal crosstalk plays a significant role in event mispositioning     

An ISPA camera for beta radiography

We have developed a new type of beta camera based on an imaging silicon pixel array (ISPA) tube combined with planar plastic scintillators or with SiY₂O₅:Ce scintillating powder. The ISPA tube consists of a photocathode viewed at 3 cm distance by a silicon anode divided into 1024 rectangular (75 μm×500 μm) detector pixels, each bump-bonded to its equally sized electronic pixel. Depending on the beta detector thickness we achieved spatial resolutions (FWHM) between 105-μm (⁶³Ni source and 30-μm-thick plastic scintillator) and 240-μm (⁹⁰Sr-⁹⁰Y source and 120-μm-thick plastic scintillator) by covering the detectors with brass templates. With their four 60-μm-wide slits oriented parallel to the long pixel edges, we simulated small-sized beta strips. The impact of detector thickness is explained by multiple scattering, angular aperture of the template slits, and scintillating light distribution at the ISPA photocathode. Beta detection sensitivities were measured with calibrated ³H (tritium)- and ¹⁴C-Amersham microscale sources. They amount to 0.1 Bq (³H) with 150 min counting time and to 0.025 Bq ( ¹⁴C) with 180 min counting time     

A novel self-biased linear silicon drift detector

A novel linear silicon drift detector (SDD) is proposed in which the proper potential profile is established by the voltage drop along a unique p⁺ cathode implanted across the surfaces. This p⁺ implant, arranged in a zigzag shape, acts at the same time as voltage divider and field cathode and allows us to increase the sensitive area, improving also the uniformity of the thermal distribution and thus minimizing the fluctuation of the electron mobility on the sensitive zone of the SDD. The perturbations of the drift field due to the asymmetry of the strips constituting the zigzag cathode have been evaluated by solving analytically Poisson's equation for a simplified model of the structure. Three-dimensional numerical simulations have been carried out to prove the negligible amount of the perturbation and the effectiveness of the proposed structure. Based on this principle, a prototype has been manufactured at Canberra Semiconductor Company. Dynamic measurements of the time-of-flight of an injected charge prove that the linearity of the prototype and the drift uniformity in the anode direction are very high     

Study of 18-cm long single-sided AC-coupled silicon microstripdetectors

The SSC GEM silicon Central Tracker design incorporated 18-cm long single-sided AC-coupled silicon microstrip ladders. Compared to the 12-cm long ladders considered in the preliminary stages of the tracker design, the 18-cm long ladders have the advantage of reduced cost, channel count and overall power consumption, and led to a simplified tracker assembly. However, such long ships also present the challenge of maintaining satisfactory performance. The increased capacitance and series resistance contribute to lower signal-to-noise ratios, longer time walk, higher power consumption per channel and increased probability of crosstalk to neighboring channels. In this paper, an accurate method to calculate the geometric capacitance of the AC-coupled microstrips is presented and the calculated results are compared with measurements, SPICE simulations are performed to predict the noise, the extent of interstrip capacitive coupling and the dispersion of the detector signal due to the finite series resistance of the metal strips and the long length of the detector. The influence of the preamplifier current and the shaping time on the signal and noise levels is also presented. The study concludes that the 18-cm long ladders can successfully satisfy the performance goals of the GEM silicon Central Tracker     

Power Mapping in a Canada Deuterium Uranium Reactor Using Kalman Filtering Technique

For a Canada Deuterium Uranium 600 MWe (CANDU 6) reactor, a new power mapping method has been developed by using detector readings as boundary conditions. In this study, the measured detector readings are combined with the diffusion theory with the Kalman filtering (DIKAL) method. The measured detector readings are transformed into the measured mesh flux through appropriate approximation. And, the difference between calculated and measured mesh flux is filtered out by Kalman filtering technique. Then, the measured mesh fluxes are used as an internal boundary condition in the diffusion equation. The performance of the DIKAL method has been assessed for the various core states, and has been also applied to the calculation of power and flux distribution calculation in the CANDU 6 reactor. Sensitivity studies have shown that DIKAL is quite stable to the detector random and systematic errors. Also, it is shown that the DIKAL approach is more accurate than the currently used flux synthesis approach in CANDU 6 reactors.     

Diminished electron cloud broadening in a silicon drift detector bysawtooth p+ strips

Already in 1993, sawtooth-shaped p⁺ strips were proposed to diminish lateral diffusion in linear multi-anode silicon drift detectors. The sawtooth structure generates small electric fields directed parallel to the detector surface and perpendicular to the drift direction. These fields confine the drifting electrons within a sawtooth period, In this paper the authors present for the first time experimental proof of the applicability of the concept. For a sawtooth period of 500 μm, we have tested the confinement of electron clouds as a function of injected charge up to 5×10⁶ electrons. The maximum number of electrons for which full confinement is achieved has been measured as a function of the potential gutter depth generated by different sawtooth angles     

The Mark II silicon strip vertex detector and performance of asilicon detector telescope in the Mark II detector at the SLC

A silicon strip vertex detector (SSVD) consisting of 36 independent silicon detector modules has been built for use in the Mark II detector at the SLAC Linear Collider (SLC). The performance of the individual modules and the stability and accuracy of their placement in the mechanical support are discussed. Top gain operational experience at the SLC, a telescope made of three silicon detector modules has been assembled and placed inside the Mark II. Results from the first data run of the SLC on the overall performance of the telescope, including backgrounds, charged particle tracking, and spatial resolution, are presented     

基于GAGG:Ce晶体耦合SiPM的位置灵敏探测器的设计与评估

为满足当前γ相机对高分辨率、低成本、小型化探测器的需求,提出了采用硅光电倍增管（SiPM）耦合GAGG:Ce晶体阵列的方式代替传统的位置灵敏型光电倍增管（PSPMT）耦合晶体阵列的方式以构成新型γ相机探测器,并设计了均匀电荷分配电路（SCDC）和阻抗电桥电路作为探测器的读出电路,同时设计了前沿定时电路作为数据采集触发电路。实验结果表明：当温度为25 ℃、探测器供电电压为28.5 V时,该探测器在511 keV射线的激发下,散点图的峰谷比高达3.84,对511 keV和662 keV射线的平均能量分辨率分别为10.63%和9.71%,具有较好的分辨性能。