4 多路单道定标器的开发

研制了一套虚拟多路定标器系统，该系统采用虚拟仪器的思想，完成了8路定标器系统，通过实验和测试，达到设计要求。根据需求，该系统扩展为80路以上的多路定标器系统，目前已有15路和72路定标器的用户采用该系统。该定标器系统的测量获取数据由计算机系统直接读入，用于分析和后续处理，各种参数设置与传统定标器相比更加灵活和方便。     

虚拟核子仪器（多道、单道等）的研究

本工作研制了虚拟单道和多道分析器。虚拟单道分析器有两种:一种为5通道、32 bit计数长度、5 MHz采样率的计数/定时定标器;另一种为8通道、32 bit计数长度、80 MHz采样率的计数/定时定标器。该虚拟定标器的界面友好,使用方便,已在研究工作中得以应用。虚拟多道分析器正在开发之     

新型核脉冲虚拟定标器设计

为实现脉冲计数的自动保存、历史数据显示和减少定标器使用者的工作量,设计了一种基于虚拟仪器技术的定标器.该虚拟定标器通过LabVIEW直接调用采集卡计数器,解决了模拟采样率低的问题.虚拟定标器功能设计围绕计数数据流展开,有效避免了功能逻辑混乱.实现了计数值自动保存,以及无人值守自动连续测量.同时该定标器硬件开放度高,可进...     

基于PCI的虚拟多通道定标器数据采集系统

利用通用的虚拟仪器软件和硬件技术，开发核领域常用核子仪器虚拟多通道定标器，可实现定数和定时工作方式，扩大虚拟仪器技术的应用领域。实验证实，该系统可实现对多路脉冲信号的精确采集，各通道间的同步良好。     

具有简易能谱分析功能的新型定标器

本文叙述了具有简易能谱分析功能的FH-454型自动定标器,它是我厂新研制出的产品。这种定标器是一种台式室内计数仪器,还备有可变增益放大器、单道脉冲幅度分析器和正(或负)高压稳压电源。它可配合G·M计数管或α、β、γ等闪烁探头,进行放射性强度测量和简易能谱分析。在电路上采用集成电路,结构上采用积木式型材,从而使整机耗电量小、重量轻、体积小,而且式样美观。     

基于DSP技术的4πβ-γ符合测量装置设计与验证

详细介绍基于DSP技术的4πβ-γ符合测量装置的硬件和软件.该装置采用自行研制的数字符合采集器代替传统的符合测量装置中的单道、门产生器、符合电路和定标器,可大大提高测量效率,降低硬件成本.通过实验验证该装置设计是成功的.     

虚拟核仪器——多路定标器

研究了虚拟仪器技术在核电子学中的应用。通过软、硬件技术的结合,完成虚拟核仪器－－多路定标器的设计。     

机助物理分析方法

单道γ能谱仪GP-1,它是由探测器,铅室、高压稳定电源、脉冲幅度分析器、稳谱装置和自动定标器等组成。该仪器体积比较庞大,电路较复杂,但每件可以单独使用,组合也比较灵活,经过多年使用已为大家所熟悉,目前仍为铀矿地质主要的物理分析仪器。 仪器的不同组合可以适应不同的物理分析方法,如应用β-γ法分析样品铀时或γ闪烁法测铀时可以选用提供探测器的高压电源及自动定标器就可。β-γ-γ能谱法综合分析样品     

核数据获取系统的几种接口电路

微机在实验核物理领域的应用可以分为两类,一类是用于处理数据,即用于数字计算,计算所需要的原始数据主要来源于多道分析器、单道分析器、定标器等获取数据的设备;另一类是把微机直接用于获取数据。当然,处理数据仍然兼之。后者,在硬件方面就     

一种基于单片机的多路定标器

本文介绍了一种基于８０３１单片机的多路定标器的主要性能和工作原理、该定标器简单、性能可靠、操作方便、可用于三路同步定时计数或定数计量测量。     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

The control system for SSRF injection and extraction

This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.     

Gamma radiation levels in the ambient environment of the QNPP Base

Monitoring results of gamma dose rate level in 1992～2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province,are reported in this paper.It is shown that the gamma dose rate of five monitoring sites of 2.5 km to QNPP Base is 84～113 nGy/h,with an average of 96 nGy/h in the 13 years.The average value is close to the background level of 93 nGy/h prior to operation of the QNPP Base,and is lower than the monitoring result of 101 nGy/h at the reference site in Hangzhou City.Within 50 km from the QNPP Base,the cumulative dose rate of the thermoluminescent dosimeter(TLD)is 90 nGy/h,which is lower than the back- ground level of 111 nGy/h.