First results from the nuclear astrophysics AMS program at the NSL using the MANTIS system in gas-filled mode

The Magnet for Astrophysical Nucleosynthesis studies Through Isobar Separation (MANTIS) system is the new Accelerator Mass Spectrometry (AMS) set-up created during recent upgrades of the Browne-Buechner spectrograph at the University of Notre Dame. Commissioning measurements performed on the separation of ⁵⁸Fe-⁵⁸Ni isobars at 114 MeV out of the FN tandem accelerator have shown clear separation, opening the door for a number of future measurements in nuclear astrophysics. The separation of mass-58 isobars has made this system the first in the world to utilise a Browne-Buechner spectrograph in gas-filled mode for AMS measurements with a special focus on nuclear astrophysics.     

平面工艺空间带电粒子探测器的研制

描述了用平面工艺＋离子注入技术制备新型空间带电粒子探测器的工艺技术及器件的特性。探测器的灵敏层厚度为100、300、450和1000μm,灵敏面积为φ8和φ12mm等不同规格。在全耗尽偏压下,得到典型的反向漏电流范围为0．57～10．11nA,典型的能量分辨率为0．69％～0．86％（对^141 Amα粒子）。在60℃高温下,器件的性能变化在空间应用的允许范围之内。     

粒子辐射探测器数据伪对数表达方法

有限的卫星通信带宽通常限制粒子辐射探测器的通道数和粒子能谱仪的分辨率.据此,提出新颖的数据压缩方案,即伪对数表达方法,来降低测量数据的存储空间,从而缓减通信压力.人们常常采用对数坐标分析粒子探测数据,因此相对误差比绝对误差更有意义.伪对数表达方法在非常小相对误差的前提下对测量数据进行了合理的压缩,有效地利用了有限的数据存储空间,既保证了数据传输的完整性,又不影响数据分析的物理意义.     

Characterisation of a pre-cell hit detector to be used in single cell irradiation experiments at the Lund Nuclear Microprobe

This paper describes the characterisation of an ultra-thin silicon semiconductor ΔE detector to be used as a pre-cell ion hit detector in single ion experiments on individual, living cells. The characteristics of interest for this specific application are the hit detection efficiency, which has to be close to 100% to enable bombardment with either a single ion or a counted number of ions, the beam spreading, which should be as small as possible to maintain the targeting accuracy, and the vacuum tightness, since the detector is intended, if possible, to be used simultaneously as vacuum window. The hit detection efficiency was shown to be above 99% when detecting alpha particles or 2 MeV protons, the increase in beam size was about 1 μm and the vacuum tightness was comparable to that of the Si₃N₄ wafer which is normally used as vacuum window, thus the ΔE detector fulfils the main criteria to function properly as a single ion hit detector.     

基于LabVIEW的探测器测试系统

介绍了构建基于LabVIEW的探测器测试系统的方法。该系统将探测器的输出信号经过放大和模数变换,得到所测的幅度谱或时间谱。模数变换由基于VME总线的峰值检测ADC实现,数据采集、谱形绘制、结果的保存通过LabVIEW编写的虚拟仪器程序完成。     

CR—39探测器的α粒子径迹研究

研究了以KOH作蚀刻液、恒温60℃蚀刻时CR-39探测器的α粒子径迹情况。实验表明,α能量越低则径迹显现时间越短;能量低至70keV时,CR-39就不能显出径迹。径迹直径随蚀刻时间延长而增大。能量1—4MeV时径迹随能量变化较快;超过4MeV时,这一变化逐渐减小。当α粒子的入射角大于40°时,实际角度和根据径迹参数而求得的角度非常一致;而小于此角时,两者相差较大。     

一套便携式高纯锗探测系统

介绍了一种可移动式高纯锗(HPGe)探测系统,利用实验室的γ放射源对探测系统的能量、效率进行刻度,全面测试了系统稳定性、成形时间等,并分析探讨该系统测量0．05～2MeVγ射线能谱的最佳工作条件及探测过程中应注意的问题。     

Two annular Csl(TI)detector arrays for the charged particle telescopes

In this study,we constructed two annular detector arrays comprising 24 wedge-shaped CsI(T1)crystals,and tested them using an α source and radioactive beams of 14-16C on a CD2 target.We compared the properties of a CsI(T1)crystal encapsulated with various reflectors,revealing that using the 80-μm-thick ESR film to pack the CsI(T1)crystal yielded the largest light output with the smallest non-uniformity in light output(ΔLO).For the 24 CsI(Tl)detectors with the 80-μm-thick ESR films,the average energy resolution improved as the average light output increased;however,it deteriorated as the ΔLO value increased.To form two annular Si-CsI(T1)telescopes for identifying the light-charged particles,the ΔLO value and energy resolution of each CsI(T1)detector were maintained under 20％and 7.7％,respectively.These telescopes were tested for the first time in a direct nuclear reaction experiment using 14-16C+d.The results demonstrated that the Z=1 and Z=2 charged particles were adequately discriminated by the telescopes using the standard ΔE-E method.     

基于嵌入式Linux的SPECT探头系统设计

设计了一套基于嵌入式Linux的单光子发射计算机断层成像(SPECT)探头系统。该系统硬件由探测器模块、数据采集模块、ARM微处理模块、网络接口模块和人机接口模块等几大模块组成。系统软件采用嵌入式Linux,并使用多线程技术。可以实现高速数据采集、实时数据校正和网络化数据通信,从而提高采集速率,减少系统死时间,提高系统的智能化和稳定性。     

Construction and performance test of charged particle detector array for MATE

A charged particle array named MATE-PA,which serves as an auxiliary detector system for a Multi-purpose Active-target Time projection chamber used in nuclear astrophysical and exotic beam Experiments(MATE),was constructed.The array comprised of 20 single-sided strip-silicon detectors covering approximately 10％of the solid angle.The detectors facilitated the detection of reaction-induced charged particles that penetrate the active volume of the MATE.The performance of MATE-PA has been experimentally studied using an alpha source and a 36-MeV 14N beam injected into the MATE chamber on the radioactive ion beam line in Lanzhou(RIBLL).The chamber was filled with a gas mixture of 95％4He and 5％CO2 at a pressure of 500 mbar.The results indicated good separation of light-charged particles using the forward double-layer silicon detectors of MATE-PA.The energy resolution of the Si detectors was deduced to be approximately 1％(σ)for an energy loss of approximately 10 MeV caused by the α particles.The inclusion of MATE-PA improves particle identification and increases the dynamic range of the kinetic energy of charged particles,particularly that of the α particles,up to approximately 15 MeV.     

Radiometric system cylindrical radiator-cylindrical endface detector

A radiometric system for radiators placed flush against the outer surface of the detector is analyzed. The geometric factors which take account of the extended nature of the detector are calculated for three values of the relative thickness. It is shown that for a detector with thickness less than 1.57 the geometric factor decreases with decreasing height of the nonabsorbing radiator, for detector thickness greater than 1.57 it increases with decreasing relative height of the nonabsorbing radiator. For an absorbing cylindrical radiator whose height is less than the diameter of the detector, the geometric factor starts to decrease with decreasing relative thickness of the radiator for detectors with any relative thickness. The larger the linear γ-ray absorption coefficient in the radiator material and the smaller the thickness of the radiator, the greater this increase. 3 figures, 1 table, 4 references. Northwest Civil Service Academy. Translated from Atomnaya énergiya, Vol. 88, No. 6, pp. 470–474, June, 2000.     

New CAMAC based data acquisition and beam control system for Lund nuclear microprobe

A new CAMAC based data acquisition system has been installed at the Lund Nuclear Microprobe facility. This paper reports on the development and present status of the data acquisition system. The system is a true multiparameter CAMAC based system with fast Fera bus readout and in crate memory buffer. The user interface is based on Sparrow Kmax software for a Power Macintosh platform. The system read out and tag the event data with position on-line, which make fast on-line monitoring of spectra or element maps possible.Simultaneously, all data can be saved event by event for off-line analysis. The beam scanning part is software controlled through a timed D/A converter, this allows fast scanning of the beam. With a CCD-camera and video card the area to be analysed could be defined directly from the image, and the sample position can be moved. Any kind of irregular scan patterns could be defined.     

Chooz 中微子探测器电子学系统的设计

介绍了Ｃｈｏｏｚ中微子探测器中的电子学系系统,简述ＥＭＩ９３５６ＫＢＡ Ｂ５３型光电倍增管的性能和组成该电子学系统的信号扇入／扇出、信号多级触发、时间数字转换、波形数字化以及数据获取等各系统的设计原理。     

BEPCII基于数字采样的鉴相器设计

在北京正负电子对撞机重大改造项目(BEPCII)中,定时系统承担的任务是对储存环以及直线的各部分设备提供同步信号,从而协调整个对撞机系统的正常运行。描述了BEPCII定时系统鉴相器的设计原理和误差分析。该鉴相器用于对BEPCII不同途径传输的两路499.8MHz信号的相位进行鉴别。采用纯数字电路,不受温度以及湿度影响。且鉴相精度在1o以内。     

核探测器的二线制电路

描述了一种核探测器二线制电路的原理和性能,并应用于核料位计中,与传统的多线制探测器相比有明显的优越性．     

First results on ion micro-tomography at LIPSION

At the nanoprobe LIPSION ion micro-tomography can be used to determine the 3D distribution information of a sample’s mass density and elemental composition. For ion micro-tomography the two analytical techniques scanning transmission ion microscopy tomography (STIM-T) and particle induced X-ray emission tomography (PIXE-T) are combined. The required data are collected in two consecutive series of measurements, during which the sample is rotated by 180°/360° in small steps. Because all ions have to traverse the sample, the upper limit of the sample size is given by the range of the ions in the material. The tomogram is obtained using the discrete image space reconstruction algorithm (DISRA) by Sakellariou (1997) [1]. This algorithm iteratively corrects a sketchy initial tomogram estimated from the experimental reconstruction – obtained by backprojection of filtered projections (BFP) – and an a priori elemental composition. The necessary correction factors are calculated comparing the reconstruction of the experimental data with the reconstruction of simulated data. For the simulated data sets of STIM projections and PIXE maps are computed from the tomogram. These data sets are proceeded with the BFP algorithm to get simulated reconstruction data. Using the DISRA for ion micro-tomography, one can benefit from the high resolution of STIM-T by transferring it to the elemental distribution given by PIXE-T. This article presents first results of this technique applied on a phantom at the LIPSION facility.     

低轨道空间闪烁探测器异常区开关机设计及控制

介绍国内首台船载空间X射线闪烁探测器（XD）在低轨道空间环境条件下,特别在南大西洋异常区,通过硬／软件在轨控制高压开／关,实现控制器辐照防护的一种高可靠,低功耗,紧凑型的一体化系统设计及其结果。     

A transition radiation detector which features accurate trackingand dE/dx particle identification

The results of a test run involving a transition radiation detector (TRD) that can distinguish electrons from pions with momenta greater than 0.7 GeV/c and simultaneously track particles passing through the detector are described. The particle identification is accomplished by a combination of the detection of transition radiation from the electron and the difference in electron and pion energy (dE/dx) in the detector. The dE/dx particle separation is most efficient below 2 GeV/c, while particle identification utilizing transition radiation is effective above 1.5 GeV/c. Combined, the electron-pion separation is better than 5×10². The single-wire, track-position resolution for the TRD is ~230 μm