直线加速器泄露辐射及杂散测试

目的通过检测型号为LA-6B 1802加速器的M区内外泄漏辐射水平和杂散并分析检测结果,评价该加速器的辐射防护安全性。方法按照检测标准WS 674—2020,使用中检普泰1000 cc球形电离室,PTW Unidose E型剂量仪和固体水,测量M区内外的泄漏辐射水平以及杂散。结果该型号加速器M区内泄漏辐射率的范围为0.009%~0.016%,平均值漏辐射率为0.012%,M区外X射线泄漏辐射率的范围为0.013%~0.053%,平均值漏辐射率为0.022%,杂散水平也均小于58%。结论该型号为LA-6B 1802加速器的辐射泄漏和杂散数据均满足标准WS 674—2020的标准要求。

国产医用加速器LA-6B剂量检测

目的对国产医用加速器LA-6B的剂量进行检测,以评估和验证其在后期治疗过程中的辐射安全性和可靠性。方法依据国家标准GB 15213—2016《医用电子加速器性能和试验方法》,使用PTW-BEAMSCAN™三维水箱、U-NIDOS剂量仪等工具对LA-6B加速器剂量进行了检测。结果对检测结果进行分析可知,LA-6B加速器X射线剂量指标均满足相关要求,且其能够提供稳定的束流照射。结论LA-6B加速器具有良好且稳定的辐射束流,确保了在后期治疗过程中的辐射安全性和可靠性。

基于波形采样的PPAC数据处理

数字化波形采样技术在实验核物理中得到了广泛的应用,选取合适的采样频率非常重要。本文使用脉冲幅度甄别定时方法和恒比定时方法对采样频率为100MHz^5GHz的平行板雪崩计数器(PPAC)信号进行了模拟分析,采样频率为250~500MHz时,使用脉冲幅度甄别定时方法可得到比较精确的位置信息,与传统获取系统定位的位置分辨的差别Sigma小于0.15mm,采样频率低于100MHz时信号定位误差较大。使用高速采样数字化仪可对信号幅度小于20mV的信号进行定时分析,与传统的PPAC获取系统相比,探测效率提升了4.3%。

5-4 A Normal-pressure MWPC Detector for Position Measurement of Intermediate and High Energy Radioactive Ions at RIBLL2

A normal-pressure MWPC detector for position measurement of intermediate and high energy radioactive ionsat RIBLL2 has been fabricated, which has a sensitive area of 75 mm100 mm and contains of three wire planes.Fig. 1 shows the layout of the MWPC wire planes.The anode plane is sandwiched between two cathodeplanes, and the anode-cathode spacing is 4 mm. Theanode plane consisted of 15 m gold-plated tungstenwires with a pitch of 2 mm. The cathode planes Xand Y , made of 60 m stainless steel wires with apitch of 0.5 mm, and every adjacent four wires are sol-dered together to form one readout strip of 2 mm inwidth. The wire directions in X and Y are orthogonalto each other, the wire direction in anode is parallel tothe wire direction in Y .

A Fission-PPAC for Fast Neutron Detection

A Fission-Parallel Plate Avalanche Counter(Fission-PPAC)has been developed for fast neutron measurements[1].The detector consists two sets of PPAC,where a ^(238)U(U_(3)O_(8))coating is put in the second set of PPAC as show in Fig.1(a)and physical map show in Fig.1(b).^(252)Cf source emits an spontaneous fission fragment and a neutron,the neutron passes through PPAC 1 and may be detected by PPAC 2 with a ^(238)U(U_(3)O_(8))coating.The total thickness of ^(238)U(U_(3)O_(8))is 600g/cm^(2),while the detection efficiency attain 8×10^(7).

Simulation of Working Gas for Fission-PPAC

The Fission-PPAC is a neutron monitor device,can use in reactor of ADS in Institute of Modern Physics,Chinese Academy of Sciences.Neutron can not be detected directly.Fast neutron can induce fission of 238U target and 238U atom split into two fission fragments.What we measure is the ionizing electron of working gas from fission fragment.Because PPAC is fast time detector,to obtain higher electron drift velocity and large signal,we must choose a suitable working gas.

5-10 Position Response of a LC Delay-line MWPC Detector

A position-sensitive MWPC detector based on LC delay-line readout has been developed for precise position measurement for experimental studies of nuclear physics.The detector consists of six electrode wire planes,which is placed in a gas chamber with a sensitive area of 100 mm×80 mm.Fig.1 shows a schematic drawing with the disposition of the six wire planes.This structure has two anode planes,each is sandwiched between two cathode planes,and the anode-cathode spacing is 4 mm.The anode plane,consist of 15 m gold-plated tungsten wires with a pitch of 3 mm.The two cathode pairs are positioned in such a way that the wires are perpendicular to each other in order to give positions at X and Y directions.The cathode planes in each pair are parallel each other in the orientation of the wires,which are made of 30 m stainless steel wires with a pitch of 0.5 mm.

用于快中子探测的裂变电离室实验及模拟结果比较

本文报道了一种用于快中子测量的裂变电离室的实验及模拟结果对比,该电离室的裂变材料为238U,分别电镀在电离室的阳极和阴极。裂变电离室通常有三种工作模式:脉冲模式、均方电压模式和电流模式,从而在大动态范围内实现中子注量测量。我们利用252Cf中子源对工作在脉冲模式的裂变电离室效率进行了测量,同时为了评估均方电压模式和电流模式,测量了裂变电离室在不同气压下的脉冲幅度,并通过Geant4蒙特卡罗软件对裂变电离室的脉冲幅度进行了模拟。模拟可以解释实验结果,当工作气压是2.64×10^5 Pa时探测效率最高[(4.30±0.7)×10^-7],且裂变碎片能谱清晰,表明裂变电离室可以工作在不同模式下。