一种大型位置灵敏平行板雪崩计数器

中国科学院近代物理研究所气体探测器组研制了一种大型位置灵敏的平行板雪崩计数器（PPAC）。它主要由中心阴极和X,Y位置阳极构成,灵敏面积为244 mm×284 mm,阴极为双面镀金1.5 μm厚的Mylar膜,阳极为直径20 μm,间距1 mm的镀金钨丝。位置读出选用延迟块读出法。这种探测器经测试在灵敏面积内位置分辨小于4 mm,时间分辨为0.42 ns,已在兰州放射性束流线（RIBLL）上清华大学的核反应实验中使用。该实验中使用了主束40Ar直接轰击Au靶,产生裂变碎片,使用了4个这种大型位置灵敏的PPAC,用来探测裂变碎片的飞行时间和速度,实验表明,PPAC对裂变碎片有90.3%的效率,给出了裂变碎片的位置分布,为理论分析工作提供了非常好的实验数据。A kind of large position sensitive parallel plate avalanche counter(PPAC) was developed at Gas Detector Research Group, Institute of Modern Physics of CAS. Each of the detector with large sensitive area of 244 mm×284 mm, consists of one central cathode, X anode and Y anode. The cathode plane in the middle of detector is a 1.5 μm thick Mylar foil coated with a thin Au-layer on both sides. The position resolution of the PPAC is better than 4 mm, and the time resolution is 0.42 ns. The detectors were used in the fission experiment with 30MeV/u 40Ar beam bombarding on a gold target to measure the velocity of the fission fragments at Radioactive Ion Beam Line In Lanzhou(RIBLL). Four PPACs were used and the experiment result showed that a rather high detection efficiency (90.3%) is achieved. The position distribution of fission fragments is given by PPACs, which provides very good experimental data for further theoretical analysis.     

重离子束用于肿瘤放射治疗的基础理论

通过与低传能线密度辐射治疗对比分析建立了重离子束肿瘤放射治疗的基础理论,提出了一些提高重离子束放射治疗疗效和减少对正常组织损伤的技术措施,旨在为已开展的重离子治癌临床研究提供理论依据． The basic theory of tumor radiotherapy with heavy ion beam was introduced in contrast to low LET irradiation therapy. Some useful methods are also suggested to improve the curative effect of heavy ion therapy and to spare the normal tissue around the tumor.     

Study of a multi-wire proportional chamber with a cathode strip and delay-line readout

The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics circuit. A very clean signal with very low background noise was obtained by applying a transformer between the delay-line and the pre-amplifier in order to match the resistance. Along the anode wire direction a position resolution of less than 0.5 mm was achieved with a ^55Fe-5.9 keV X ray source. The simple structure, large effective area and high position resolution allow the application of a gas chamber of this kind to many purposes.     

Delay line readout of a large dimension multi-wire proportional chamber

A two dimensional multi-wire proportional chamber with delay line readout was developed, which has a large sensitive area of 30 cm× 30 cm. Two cathode planes using printed circuit boards are orthogonally placed to give two coordinates of the impact point of the particle. Signals collected from the cathode strips are amplified and discriminated from two ends of the delay line at each cathode board. By recording the time difference between the two discrimination pulses and the common gate pulse from anode wires, a coordinate position was reconstructed, and a position resolution of better than 1 mm could be obtained in the whole sensitive area along the anode wires.     

用于高能轻粒子探测的延迟线PPAC(英文)

气体探测器有成本低廉、制备简单、性能可靠和方便使用等特点。研制了一种5层板结构的延迟线平行板雪崩电离室（PPAC）,用于兰州放射性束流线（RIBLL）上开展的实验。在57.6 MeV/u的6He束流条件下测试了这种探测器对高能轻粒子的适用性,得到了位置分辨为1.8 mm (FWHM), 时间分辨为2.6 ns, 以及可靠的探测效率。The gas detectors have the characteristics of low cost, easy preparation, reliable capability and convenient for use etc. A delay line parallel plate avalanche counter(PPAC) with five plates has been developed for the experiments at Radioactive Ion Beam Line in Lanzhou(RIBLL). The applicability of counter for high energy light ion has been tested with 57.6 MeV/u 6He beam. A position resolution of ~1.8 mm(FWHM) and a timing resolution of ~2.6 ns are achieved. The detection efficiency is reasonable.     

A normal-pressure MWPC for beam diagnostics at RIBLL2

A normal pressure MWPC for beam diagnostics at RIBLL2 has been developed, which has a sensitive area of 80mm×80mm and consists of three-layer wire planes. The anode plane is designed with a wider frame to reduce the discharge and without using protection wires. The detector has been tested with a (55)Fe X-ray source and a 200 MeV/u(12)C beam from CSRm. A position resolution better than 250 μm along the anode wires and a detection efficiency higher than 90% have been achieved.     

A position resolution MRPC for muon tomography

Muon tomography is a promising method in the detection and imaging of high Z material. In general, considering the quality of track reconstruction in imaging, a detector of good position resolution, high efficiency and large area is required. This paper presents the design and study of a prototype of position sensitive MRPC with 0.15 mm narrow gas gap and 2.54 mm strip readout. Through a cosmic-ray experiment, the performance of MRPC module is carefully observed and each channel is calibrated. Through an X ray experiment with a narrow slit, the position resolution is studied. The results show that the time resolution of the module can reach 61ps and the spatial resolution can reach 0.36 mm.     

重离子治癌的磁扫描照射野形成法

在论述重离子治癌照射的基本思想及其特点的基础上,着重对磁扫描照射野形成的两种技术路线——点扫描和栅扫描的优缺点进行了分析阐述.初步给出了 HIRFL上的重离子治癌终端磁扫描相关参数. The basic principle and characteristic of irradiation in heavy ion radiotherapy are introduced. Based on the basic principle and characteristic of irradiation in heavy ion radiotherapy, two magnetic scan methods for creating uniform irradiation field--the spot scan and the raster scan, are compared briefly. The parameter requests to the magnetic scanning system of the heavy ion radiotherapy facility planned in IMP(Institute of Modern Physics) are presented.     

重离子束适形放射治疗技术

重离子束适形放射治疗技术主要包括束流配送系统和治疗计划系统等 .前者是实现重离子束适形放射治疗的硬件设施 ,后者为适形治疗的软件支撑系统 ,两者缺一不可 .鉴于重离子束与物质相互作用在物理学及生物学效应上表现出的特殊性,重离子束治癌中特别引入了面向生物学效应的适形治疗和束流的正电子断层在线监控技术. The conformal radiotherapy techniques mainly include the two systems that are beam delivery and treatment planning. The formal is the hardware basis while the later is the software supplement for heavy ion conformal therapy, they are dependent on each other to realize the cancer conformal therapy with heavy ion beam. Because of the specificities of interaction between heavy ion and target on both physics and biological effects, the heavy ion cancer therapy especially involves...     

Design and performance of a 2-D multi-wire position sensitive X-ray detector

A 2-D multi-wire position sensitive detector for X-ray diffraction and small angle X-ray scattering studies is described. The detector has an active area of 100 mm × 100 mm and consists of an anode plane with 10 μm SS wires at 3 mm spacing and a pair of orthogonal cathode readout planes with 25 μm SS wires placed at 1.5 mm spacing. The position information is obtained using charge division method and recorded using a laboratory built data acquisition system. The resolution and gas gain was measured for 5.9 keV X-rays (⁵⁵Fe-source) as a function of the anode wire voltage and gas pressure. It was observed that the proportional region of the PSD at 100 kPa pressure extended up to a high voltage value of around 1.5 kV and it shifted to high values up to 2 kV for gas pressure of 300 kPa. The energy resolution improved from 18% (FWHM) to 12% with increase in pressure. The spatial resolution of the PSD also showed improvement, with a value of 1.2 mm × 1.4 mm at 300 kPa gas pressure. A maximum gain of 5 × 10⁴ is obtained.     

PPAC在单粒子效应地面模拟实验中对束流均匀度测量的应用

单粒子效应(SEE)加速器地面模拟需要离子束具有较好的均匀度,针对回旋加速器单粒子效应模拟的束流特点,建立了一套以位置灵敏平行板雪崩探测器(Parallel Plate Avalanche Counter,PPAC)为基础的均匀度探测系统并完成了带束测试,对它的结构、工作原理、均匀度获得方法及带束测试结果进行描述。为验证PPAC测量结果准确性,在带束测试过程中,前方同时放置PET膜测量穿过PPAC探测器的粒子分布,与离子径迹测量结果对比,给出PPAC的均匀度的测量误差在5%之内。探测器具有50 mm×50 mm的灵敏面积和小于1 mm的位置分辨,符合单粒子效应实验对束流均匀度测量的要求。     

基于LC延迟电路的双层多丝正比室的研制

描述了为兰州放射性粒子束流线（RIBLL Ⅱ）上测量束流径迹而研制的一种基于LC延迟电路的双层多丝正比室（MWPC）。该探测器的探测灵敏面积为100 mm×80 mm,位置信号由阴极丝引出并通过LC延迟电路读出。探测器由两套完整的多丝正比室组成,每套的阳极丝夹在两层平行的阴极丝之间,阳极丝和阴极丝相互垂直。两套阴极丝相互垂直给出入射粒子的二维位置信息。为了增大感应信号以提高探测效率,将每套位置对应的阴极丝合并成一路接入LC延迟电路。用55Fe-5.9 keV X射线源均匀照射探测器的灵敏区域,测试表明其具有良好的位置灵敏一致性。用X射线源通过准直狭缝扫描整个探测器的灵敏区域,得到X,Y层的位置线性度均好于0.999;其位置分辨（σ）分别为199.9 μm和154.0 μm,目前,该探测器已成功用于RIBLL Ⅱ的实验中。A double-layer Multi-Wire Proportional Chamber (MWPC) with 100 mm×80 mm active area has been developed for Radioactive Ion Beam Line in Lanzhou(RIBLL Ⅱ). The position information has been obtained by a LC delay circuit readout method. Being called of double-layer MWPC, it is composed of two full MWPCs, each consists of an anode plane sandwiched between two parallel cathode planes, anode wires and cathode wires are perpendicular to each other. In order to improve the detection efficiency, the cathode wires of corresponding position are combined to enhance inductive signal. The cathode wires of two full MWPCs are orthogonally placed to give two coordinates of the incident particles. The sensitivity uniformity is also found to be relatively good and the position resolution of X, Y direction are measured to be 199.9 and 154.0 μm using a 55Fe-5.9 keV X ray, respectively. The position linearity of X, Y direction are as good as 0.999 for whole sensitive area of the detector. The detector has been used successfully on the experiment at RIBLL Ⅱ.     

一种多阳极横向场电离室

描述了一种将用于兰州放射性束流线较重离子鉴别的多阳极横向场电离室.对其性能进行了初步测试,得到该电离室有较长的坪区和较好的能量分辨.在10⁴Pa的P10工作气体(10%CH₄+90%Ar)下,坪区长度为700V.对²⁴⁴Cm α放射源,在第4片阳极对应的灵敏区域能量损失为1.30MeV,能量分辨41.1keV,相对能量分辨约3.16%。     

PERFORMANCE OF THE PARALLEL MULTIPLATE AVALANCHE CALORIMETER

This is the first try to use PPAC as sampling calorimeter. The article is discussing the possible fluctuations in this type of calorimeter, presenting the results of simulating measurements performed on single gap PPAC and actual measurements for multiplate PPAC calorimeter. It is prospected that the energy resolution could be 17%/√E, if using 2 mm Pb plates as absorbers.     

Design and experimental study of a two-dimensional position sensitive X-ray detector

A prototype of a two-dimensional position sensitive X-ray detector was designed and constructed for small angle X-ray scattering experiments at BSFR (Beijing Synchrotron Radiation Facility). The detector is based on MWPC with cathode strip readout, and has a sensitive area of 200 mmx200 mm. The spatial resolution (FWHM) of about 210 μm along the anode wire direction was obtained from the 55Fe X-ray test of the detector.     

Staudruckmessungen an der Anode von Hochstromlichtbögen

A measuring method and system is described for the determination the dynamic (stagnation) pressure in the anode spot of high current arcs or in the near of it, and in any plasma without or with current. For this use a movable cooled or uncooled anode has small bore hole of 1 to 1,5 mm diameters perpenticular to its surface. These holes are connected at a steel membran by a short hose line. The membran deflections caused by dynamic pressure are measured by means of an inductive path measuring system and recorded by a storascope. The attained spatial resolution is 0,5 mm, the time resolution is 0,025 s, and the limiting sensitivity is lower than 0,1 Torr. The method was applicated to plasma welding arcs up to 700 Amps. It enabled the determination of dynamic pressures down to 0,3 Torr inertialess and free from distortions.     

散裂中子源高气压二维位置灵敏3He探测器的实验研究

为满足中国散裂中子源多功能反射谱仪中子探测器的基本物理要求:有效面积达到200 mm×200 mm、探测效率大于50%（2Å）、位置分辨好于2 mm等,中国科学院高能物理研究所研制了3He高气压二维多丝正比室位置灵敏中子探测器。该探测器采用二维多丝室结构,腔体内充3He/C₃H₈（6 atm/2.5 atm）的组合气体。本文首先利用Am/Be中子源完成对探测器全面积均匀性测试,均匀性指标达到了95.1%;探测器在中国散裂中子源的20号束流线站安装后,对其进行了在束测量,通过飞行时间选取波长2.8Å的慢中子,测量了探测器二维位置分辨和二维成像性能。在X方向（垂直于阳极丝的方向）的位置分辨为0.99 mm,Y方向（平行于阳极丝的方向）的位置分辨为1.36 mm,探测器具有很好的二维位置分辨和二维成像能力。测量结果表明探测器满足反射谱仪的研制要求。