DAMPE silicon tracker on-board data compression algorithm

The Dark Matter Particle Explorer(DAMPE) is an upcoming scientific satellite mission for high energy gamma-ray, electron and cosmic ray detection. The silicon tracker(STK) is a subdetector of the DAMPE payload.It has excellent position resolution(readout pitch of 242 μm), and measures the incident direction of particles as well as charge. The STK consists of 12 layers of Silicon Micro-strip Detector(SMD), equivalent to a total silicon area of6.5 m2. The total number of readout channels of the STK is 73728, which leads to a huge amount of raw data to be processed. In this paper, we focus on the on-board data compression algorithm and procedure in the STK, and show the results of initial verification by cosmic-ray measurements.     

A 3 × 6 arrayed CCD X‐ray detector for continuous rotation method in macromolecular crystallography

A 3 × 6 arrayed charge‐coupled device (CCD) X‐ray detector has been developed for the continuous‐rotation method in macromolecular crystallography at the Photon Factory. The detector has an area of 235.9 mm × 235.9 mm and a readout time of 1.9 s. The detector is made of a 3 × 6 array of identical modules, each module consisting of a fiber‐optic taper (FOT), a CCD sensor and a readout circuit. The outputs from 18 CCDs are read out in parallel and are then digitized by 16‐bit analog‐to‐digital converters. The advantage of this detector over conventional FOT‐coupled CCD detectors is the unique CCD readout scheme (frame transfer) which enables successive X‐ray exposures to be recorded without interruption of the sample crystal rotation. A full data set of a lysozyme crystal was continuously collected within 360 s (180° rotation, 3 s/1.5° frame). The duty‐cycle ratio of the X‐ray exposure to the data collection time was almost 100%. The combination of this detector and synchrotron radiation is well suited to rapid and continuous data collection in macromolecular crystallography.     

Readout electronics testing of the CMS Tracker modules with LT setup

The tracking part of the CMS detector will be built with ∼16000 silicon detector modules, and kept at −10°C for the ten years of the operation of the LHC. All the model materials need to be verified of having a good performance at this low temperature, before their installation into the CMS Tracker. In order to track performance quality, assurance tests are done with two different systems. Of the two setups used, the LT system module is the one that is used to identify whether the performance of readout electronics and leakage current flowing on the silicon sensors is affected by low temperature. In this paper a detailed layout of the CMS TOB modules and their front-end hybrids are presented. In addition, the LT testing results of the 190 TOB modules that were produced and tested in 2004 by the FNAL-CMS group are given. The text was submitted by the author in English.     

工作气体对MRPC性能影响的研究

多气隙电阻板室(MRPC)飞行时间探测器模型从2003年2月开始在美国布鲁克海文国家实验室(BNL)的AGS束流上顺利完成了为期10周的测试(共28个MRPC模块168路读出,其中12个模块即72个读出道配置了读出电子学).实验表明工作气体的选择对MRPC的工作性能有很大影响.测量了几种不同成分的混合气体(A)90%C₂H₂F₄+5%iso-C₄H₁₀+5%SF6、(B)95.3%C₂H₂F₄+47%iso-C₄H₁₀及(C)100%C₂H₂F₄下MRPC探测效率和时间分辨等特性的变化,并给出了相应条件下的流光信号几率     

多阳极位置灵敏光电倍增管位置读出电路的设计实现

多阳极位置灵敏光电倍增管（PSPMT）被广泛地用来开发高分辨的小型γ相机模块。探讨了PSPMT的位置读出电路的简化设计研究, 并针对日本滨松的H8500型多阳极PSPMT, 设计和开发了离散位置读出电路（DPC）和均衡电荷分配电路（SCDC）两种简化的位置读出电路, 并在SCDC中加入了局域重心（TCOG）的定位方法, 进一步地优化读出电路的简化设计。初步的实验测试结果表明, SCDC结合TCOG定位法, 能显著地改善探测器的定位非线性及压缩效应, 扩展有效的成像视野（FOV）, 比DPC方法的有效视野增大了约20%。The multi anode position sensitive photomultiplier tube(PSPMT) has been used for the development of high resolution γ camera module. This study is aimed to investigate the simplified readout design for the multi anode flat panel PSPMT. Based on the Hamamatsu H8500 PSPMT with 64 multi anodes, we designed and developed two simplified readout circuits, discretized positioning circuit(DPC) and symmetric charge division circuit(SCDC). The truncated center of gravity(TCOG) positioning method was used to optimize the readout signal processing and then further reduce the readout channels by a resistor chain. The preliminary results show that the SCDC readout with the TCOG could significantly reduce the non linearity of positioning and improve the effective field of view of the detector by about 20% as compared to the DPC readout.     

A prototype scalable readout system for micro-pattern gas detectors

A scalable readout system(SRS) is designed to provide a general solution for different micro-pattern gas detectors in various applications.The system mainly consists of three kinds of modules:the ASIC card,the adapter card and the front-end card(FEC).The ASIC cards,mounted with particular ASIC chips,are designed for receiving detector signals.The adapter card is in charge of digitizing the output signals from several ASIC cards.The PEC,edged-mounted with the adapter,has field-programmable gate array(FPGA)-based reconfigurable logic and I/O interfaces,allowing users to choose different ASIC cards and adapters for different experiments,which expands the system to various applications.The FEC transfers data through Gigabit Ethernet protocol realized by a TCP processor(SiTCP) IP core in FPGA.By assembling a flexible number of FECs in parallel through Gigabit Ethernet,the readout system can be tailored to specific sizes to adapt to the experiment scales and readout requirements.In this paper,two kinds of multi-channel ASIC chip,VA140 and AGET,are applied to verify the scalability of this SRS architecture.Based on this VA140 or AGET SRS,one FEC covers 8 ASIC(VA140) cards handling 512 detector channels,or 4 ASIC(AGET) cards handling 256 detector channels,respectively.More FECs can be assembled in crates to handle thousands of detector channels.     

Back-n波形数字化模块的数据实时读出方法

Back-n是中国散裂中子源（CSNS）的反角中子束线,适用于精密核数据的测量。该装置的谱仪读出电子学采用共性化设计方法,利用高速波形数字化技术精密采集探测器输出信号波形。为完成对两通道、1 GSps,12 bit采样数据的读出和板载外设的控制,可以使用一种基于FPGA的高速数据实时读出方法。该方法不仅实现了数据接收、缓存上传等通用需求,还通过软件配置满足了实时触发处理等针对特定物理实验的特性需求。此外,FPGA的灵活使通过固件更新支持新实验或添加新功能成为可能。测试结果表明,该方法能够适应Back-n波形数字化模块高速数据读出的需求,峰值处理能力可达24 Gbps,符合物理实验需求。目前,基于实时读出方法实现的波形数字化模块已完成中子源谱仪实验现场的安装,工作稳定。Back-n is a back-streaming beam line at China Spallation Neutron Source, which is suitable for measure nuclear data precisely. The readout electronics of the spectrometers at this facility adopts general-propose design method, using high-speed waveform digitizing technology to record the detector output signal accurately. To read out two channels, 1 GSps, 12 bit sample data and control on-board devices, the real-time readout method of high-speed data based on FPGA technology can be considered. The method not only realizes the general requirements of the data upload, but also processes real-time triggers according to experiments via configuration. In addition, due to the flexibility of FPGAs, new experiments or new features can be supported through firmware updates. The test results show that the method is suitable for the high-speed data readout of field digitizing module at Back-n and peak capacity reaches up to 24 Gbps, which meets the requirements of the physical experiment. The field digitizing modules based on this method were installed at Back-n and work normally.     

Dose reassessment by using PTTL method in MTS-N (LiF:Mg,Ti) thermoluminescent detectors

The thermoluminescent (TLD) method is one of the most commonly used in dose measurements in radiation protection dosimetry. Due to its many advantages this method is widely spread. However, TLD has especially one disadvantage which is very inconvenient: the dose information in already read detectors is erased and in routine standard way the dose can not be reassessed. The positive is that this shortcoming can be eliminated by applying UV radiation. After first readout the same detector can be subjected to UV exposure and then read once again to reassess the dose.This method for reassessment of dose is based on phototransferred thermoluminescence (PTTL). In an irradiated TL detector deep traps are not emptied during the first readout. During exposure to UV, electrons are transferred from deep traps to shallower dosimetric traps. This TL signal emerging during the second readout following UV illumination is called phototransferred thermoluminescence.A method for reassessment of dose in a previously readout TLD is presented in this work. Experiments show that the method works well within region of doses between 5 and 50 mGy, but could be applied for higher doses as well. The efficiency of dose reassessment reaches about 17 percent of the first readout.The method could be a noticeable improvement in TLD dosimetry, giving more opportunities for better control and reliability of measurements.     

Non‐uniform nanosecond gate‐delay of hybrid pixel detectors

A simple experiment to characterize the gating properties of X‐ray area detectors using pulsed X‐ray sources is presented. For a number of time‐resolved experiments the gating uniformity of area detectors is important. Relative gating delays between individual modules and readout chips of PILATUS2 series area X‐ray detectors have been observed. For three modules of a PILATUS 300K‐W unit the maximum gating offset between the modules is found to be as large as 30 ns. On average, the first photosensor module is found to be triggered 15 ns and 30 ns later than the second and the third modules, respectively.     

基于阻性阳极读出方法的气体电子倍增器二维成像性能

新型微结构气体探测器,如气体电子倍增器(gas electron multiplier,GEM)等,具有非常好的位置分辨率潜力(σ100μm),但是需要匹配大规模高密度的读出电子学,给探测器的建设、造价、功耗、空间利用等带来极大压力.阻性阳极读出方法可以在保持较高位置分辨率的前提下,大幅节省电子学.基于厚膜电阻工艺,一种新的阻性单元阵列结构被成功开发和应用于三级级联GEM探测器的读出阳极.该阻性阳极包括6×6个6 mm×6 mm的基本阻性单元,仅需匹配49路读出电子学.~(55)Fe放射源(5.9 keV)和X光机(8 keV)实验的结果显示探测器的位置分辨率(σ)可好于80μm,位置非线性好于1.5%.同时,探测器还获得了很好的实物成像效果.探测器的优良性能表明这种阻性阳极读出方法适用于大面积二维成像气体探测器的读出,并可用于其他探测器的读出.     

非制冷红外探测器读出电路的非均匀性研究

对于长线列的非制冷红外探测器组件, 不同探测元之间的非均匀性是衡量电路设计的关键指标. 为了实现长线列非制冷红外探测器的高性能读出, 本文设计了一种基于电流镜方式的非制冷红外探测器160线列读出电路, 电路由电流镜输入模块、电容负反馈互导放大器模块及相关双采样输出模块组成. 电路采用0.5 μm工艺制作完成. 通过合理设置电路中MOS管的参数和布局电流镜版图, 电路的非均匀性有了明显地改善. 通过测试, 电路的非均匀性小于1%, 器件总功耗约为100 mW, 并具有良好的低噪声特性, 输出噪声小于1 mV, 输出摆幅大于2 V. 该电路与160线列非制冷红外探测器互连后, 能较好地完成红外信号的读出, 在积分时间为20 μups的情况下, 器件的响应为0.294 mV/Ω, 整体性能良好. 该电路的研制对超长线列的非制冷红外冷探测器读出电路研制奠定了重要的技术基础.     

Beam test of CSES silicon strip detector module

The silicon-strip tracker of the China Seismo-Electromagnetic Satellite(CSES) consists of two doublesided silicon strip detectors(DSSDs) which provide incident particle tracking information.A low-noise analog ASIC VA140 was used in this study for DSSD signal readout.A beam test on the DSSD module was performed at the Beijing Test Beam Facility of the Beijing Electron Positron Collider(BEPC) using a 400–800 MeV/c proton beam.The pedestal analysis results,RMSE noise,gain correction,and intensity distribution of incident particles of the DSSD module are presented.     

Dark-matter search with CRESST

The CRESST experiment is looking for non-baryonic particle dark matter via nuclear scattering in CaWO₄. The simultaneous measurement of the heat and the scintillation light generated by an event in a CaWO₄ single crystal is used to discriminate between electron and nuclear recoils thanks to their different light output. This allows an efficient suppression of the electron recoil background. The set-up consists of modules with a 300 g CaWO₄ crystal mounted in a reflective housing together with a light detector. The heat signal is read out using a superconducting transition-edge sensor (TES) made of tungsten evaporated directly on to the crystal that is operated at a few mK. Currently the second phase of the experiment is being set up at the Laboratori Nazionali del Gran Sasso in which it is planned to run 33 detector modules providing a total target mass of 10 kg. First test runs with prototype detectors have been successfully performed. Presented by W. Westphal at the Workshop on calculation of double-beta-decay matrix elements (MEDEX’05), Corfu, Greece, September 26–29, 2005.     

Detection of a single electron in xenon-based electroluminescent detectors

It is experimentally shown that a single ionization electron can be detected by various xenon-based electroluminescent detectors with optical readout, such as a high-pressure cylindrical gas counter, a two-phase detector with gas amplification, and a two-phase detector with a plane-parallel and uniform electric field. The sensitivity of the detectors was 7, 18, and 15 photoelectrons respectively. The coordinate resolution of the two-phase detector for electrons resulting from field emission at the cathode was σ _X,Y = 5.2 mm.     

sTGC前端电子学批量测试系统设计与应用

ATLAS探测器PHASE Ⅰ升级过程中,将新建NSW探测器用于提高对Muon轨迹的探测效率,从而进一步提高一级触发效率。NSW由768个sTGC探测器模块组成,共计约33万探测通道。中国科学技术大学代表中国合作组承担了全部sTGC前端读出电子学设计和生产任务,开发了用于读出strip信号的s FEB读出板和读出pad与wire信号的pFEB读出板,制定了一套完整的FEB测试方案和测试流程。为了对生产完成的上千块FEB进行批量测试,严格按照sTGC读出系统要求,设计了能够同时测试FEB板704通道的多参数批量测试系统。利用FEB批量测试系统,完成了全部850块pFEB和sFEB板测试,并交付ATLAS合作组安装到了sTGC探测器上。     

Comparison between blue and green stimulated luminescence of Al2O3:C

This paper presents a systematic comparison of OSL signals from Al₂O₃:C when stimulated with blue and green light. Al₂O₃:C detectors were irradiated with various doses and submitted to various bleaching regimes using yellow, green and blue light. Most of the investigations were carried out using Luxel?-type detectors used in the commercial Luxel? and InLight? dosimetry systems (Landauer Inc.). Al₂O₃:C single crystals and Al₂O₃:C powder were also used to complement the investigations. The results show that, although blue stimulation provides faster readout times (OSL curves that decayed faster) and higher initial OSL intensity than green stimulation, blue stimulation introduced complicating factors. These include incomplete bleaching of the dosimetric trap when the Al₂O₃:C detectors are bleached with yellow or green light and the OSL is recorded with blue light stimulation, and an increased residual level due to stimulation of charge carriers from deep traps. The results warrant caution when using blue stimulation to measure the OSL signal from Al₂O₃:C detectors, particularly if the doses involved are low and the detectors have been previously exposed to high doses.     

Photon dosimetry methods outside the target volume in radiation therapy: Optically stimulated luminescence (OSL), thermoluminescence (TL) and radiophotoluminescence (RPL) dosimetry

Dosimetry methods outside the target volume are still not well established in radiotherapy. Luminescence detectors due to their small dimensions, very good sensitivity, well known dose and energy response are considered as an interesting approach in verification of doses outside the treated region. The physical processes of thermoluminescence (TL), radiophotoluminescence (RPL) and optically stimulated luminescence (OSL) are very similar and can be described in terms of the energy band model of electron-hole production following irradiation.This work is a review of the main dosimetric characteristics of luminescence detectors which were used in experiments performed by EURADOS Working Group 9 for in-phantom measurements of secondary radiation (scattered and leakage photons). TL LiF:Mg,Ti detectors type MTS-7 (IFJ PAN, Poland), types TLD-100 and TLD-700 (Harshaw), OSL Al₂O₃:C detectors type nanoDot™ (Landauer Inc.) and RPL rod glass elements type GD-352M (Asahi Techno Glass Coorporation) are described. The main characteristics are discussed, together with the readout and calibration procedures which lead to a determination of absorbed dose to water.All dosimeter types used show very good uniformity, batch reproducibility and homogeneity. For improved accuracy, individual sensitivity correction factors should be applied for TL and OSL dosimeters while for RPL dosimeters there is no need for individual sensitivity corrections.The dose response of all dosimeters is linear for a wide range of doses.The energy response of GD-352M type dosimeters (with Sn filter) used for out-of-field measurements is flat for medium and low energy X-rays.The energy dependence for TLDs is low across the range of photon energies used and the energy correction was neglected. A significant over response of Al₂O₃:C OSLDs irradiated in kilovoltage photon beams was taken into account. The energy correction factor f_en was calculated by using the 2006 PENELOPE Monte Carlo code.With suitable calibration, all dosimeter types are appropriate for out-of-field dose measurements as well as for the in-phantom measurements of radiotherapy MV X-rays beams.     

The calculation of the speed performance of the CLAS12 silicon vertex tracker

The CLAS12 experiment is intended to study the generalized parton distributions in exclusive reactions. The CLAS12 Silicon Vertex Tracker must provide the registration of all reaction products at the expected high luminosity. The results of a GEANT4 simulation of the expected physical rates in the SVT are presented. The frequency of the noise hits of the readout electronics is determined on the basis of the capacitive load generated by the attached sensors. In order to find the fraction of the events that are lost due to delays in the readout electronics, a computer simulation of the logic of the data-driven readout FSSR2 chip is performed. At a signal-to-noise ratio of 8 to 1 the readout electronics are capable of processing the expected rates, provided a registration threshold of 0.4 mip is preset.     

用于CBM-TOF超级模块质量评估的SoC数据读出方法

在高压缩重子物质（Compressed Baryonic Matter,CBM）实验中,多气隙电阻板室（Multi-gap Resistive Plate Chamber,MRPC）探测器被用于构建飞行时间（Time of Flight,TOF）谱仪。根据CBM实验需求,TOF谱仪被设计成由6种不同类型的超级模块构成的探测器墙。每个模块最多包含5块MRPC探测器,能提供320路电子学通道,单个模块的数据率高达6 Gbps。为了评估CBM-TOF超级模块的性能,本文提出了一种基于TCP/IP千兆以太网技术的数据读出方法。考虑到TCP/IP协议的复杂性,该方法利用AlteraSoC FPGA从前端电子学接受数字化的时间数据,并通过千兆以太网并行地发送数据到DAQ软件。实验室测试结果表明,单个读出扣板全链路读出速率达到550 Mbps,能够用于CBM-TOF MRPC探测器质量评估。