FMJ-δ2微电脑放射免疫γ计数器的研制

本文介绍一种基于微电脑的智能放射免疫γ计数器。仪器的样品传送、数据获取、数据处理和测量结果输出皆由微电脑控制执行。它的测量效率>76％,本底<70cpm(对于~(125)I),计数时间分辨率<50ns,样品容量一次250并有四种数据处理方式。     

普及型放免γ计数器

我们研制的普及型γ计数器只需转动一下开关就可以改变测量放射性同位素的品种,基本上达到了一机多用和操作简便的目的。在设计时,我们还注意了降低造价的问题,以便更好地实现普及。     

FD-136型γ找水仪

本文介绍了利用天然放射性自然本底的变化来寻找地下储水构造的原理,并且分析,比较了各种测量方法和各种可利用的探测器优缺点。从而确定了仪器设计方案。在设计过程中重点解决了γ射线低能响应和电子电路的功耗问题。最后介绍了仪器野外试验情况。     

配接MIC-80微机的液体闪烁测量系统中样品化学发光的检测及该系统程序中一些问题的考虑

一、样品化学发光的估算 与淬灭现象相反,样品化学发光在液闪测量中会导致假计数。为此,在每次建立新的样品制备方法之后都需估计该方法是否会导致化学发光,若有,还要估计它对测量结果影响的程度。已有多种检测化学发光的方法报道,但大多有各自的缺点:用不含放射性的对照样品的方法则比较费时间:用双重外标准源道比法需专门绘制一条标准曲线且在淬灭严重时检测有困难;用延迟符合的技术则需要增加电子学线路。在我们的配接了MIC-80微机的YSJ型液闪仪上,当进行化学发光检测时,仪器会自动给出样品化学发光的估算值nc。若nc=0,则可肯定样品无化学发光或者说化学发光对测量结果无影响;若nc≠0,则提示我们,该样品可能有化学发光存     

小容量液体闪烁测量系统在放射免疫分析中的应用研究

国外有人将400μl锥形管用于液体闪烁测量,但未见用于RIA。我们根据H数猝灭校正的特点,即不受测量杯质地及闪烁液容量的影响,并考虑到闪烁液的样品容纳能力,改进了氚标RIA样品制备方法,将RIA样品加到12×50mm具盖聚乙烯管中,加1ml闪烁液进行测量。已用于睾酮(T)、雌二醇(E_2)、雌三醇(E_3)、氯丙嗪(CPZ)等放射免疫分析。实践证明其操作方便,结果可靠,比常规方法节省80％的闪烁液。     

微机在核计数系统中的应用

本文介绍一种基于微机的采用软-硬件结合传送方式的智能计数系统及其管理程序。接口电路所需的硬件很少,又能获得很小的分辨时间(<0.1μs)。管理程序使仪器具有一定编辑能力,能定时或定误差地进行数据获取,显示已获取的数据并打印出结果。这种智能计数器具有在线数据处理能力,其性能价格比比一般定标器优越得多。     

YSJ-76液闪计数仪配接AppleⅡ微机

1976年我们与上海交大微机研究室合作成功地实现了YSJ-76液闪仪与Mic-80微机的配接工作,使仪器具有了数据处理和自动控制的功能。随着近年来放射免疫分析法和放射配基受体分析法的进展,对数据处理、质量控制提出了更高的要求。原来的液闪仪Mic-80系统的功能就显得有所不足,主要是数据不能保存,数据处理不够完善,此外操     

液体闪烁测量~(125)Iγ射线方法的研究

在液体闪烁液中加入重金属元素,就可用液体闪烁法测量γ射线。本文对~(125)I的液体闪烁测定条件进行了探讨,并应用~(125)I放射免疫的样本同时在γ谱仪和液体闪烁仪上测定并比较,确定~(125)I液体闪烁测定的可行性。这样可以提高~(125)I样本测定的自动化程度和实现液体闪烁仪一机多用。     

4πβ-γ符合装置微机在线处理

本文着重叙述了拟定联机接口方案的基本方法,并在设计中采用了一些必要的技术措施,满意地建立了4πβ-γ符合装置微型计算机在线处理系统,进一步完善了4πβ-γ符合装置的性能,改善了实验条件,显著地提高了工作效率和测量结果的准确度。     

冠心病患者血小板GMP—140RIA的研究

应用单克隆抗体ＳＺ－５１，通过放射免疫分析测定了９４例冠心病患者血小板α颗粒膜蛋白的活化分子数。实验结果表明：冠心病组患者血小板ＧＭＰ－１４０分子数比正常对照组明显增高；急性心肌梗塞患者用尿激酶溶栓治疗后１２ｈ的血小板ＧＭＰ－１４０的活化分子数比治疗前１ｈ明显降低。     

New Technical Approach to Monitoring of Low-Level Environmental Gamma Radiation Using NaX(Tl) Scintillation Instrument

The environmental dose evaluation around a nuclear facility is usually performed by means of calculational methods on the basis of effluent monitoring at a release point. It has been desired to develop practical techniques of direct monitoring in the environment, because the Japan Atomic Energy Commission set up 5 mrem/yr as an objective dose value for the whole-body exposure due to normal operation of LWRs on a single site.

In evaluating gaseous plume doses less than 5 mrem/yr in routine monitoring, there are many difficult problems to be solved. We have developed two techniques for separation of the plume exposures less than 1 mrem/yr from the background radiation, using a NaI(Tl) scintillation counter having flat energy response.

One technique is based on the difference in energy spectrum distribution between plume gamma and natural gamma radiation. And, separation of the respective exposures is made by analysis of the two informations obtained by a two-channel monitoring system. Another technique is to reduce the natural gamma radiation components by using a special concave lead shield for the NaI(Tl) scintillation probe. A combination of the techniques can much improve the efficiency of separation of ⁴¹Ar plume radiation from fluctuating background radiation.     

A Large Area Thin Nal(Tl) Detector for External Counting of Low-Energy Emitters in Lung

A new type lung monitor was designed for the detection of ²³⁹Pu and ²³⁵U in the lungs, and a preliminary calibration undertaken thereon. The detector consists of a 9.5 in. dia. by 0.5 in. thick NaI(Tl)-crystal and seven photo-tubes. Besides its use as an ordinary lung monitor, the instrument can be employed as an image detector giving a rough indication of the distribution of the activities in the lungs. This paper describes the structural arrangement of the detector, the preliminary calibration performed thereon and the limits of detection derived as function of the subject's effective tissue thickness.     

A new value for the half-life of Be by Heavy-Ion Elastic Recoil Detection and liquid scintillation counting

The importance of ¹⁰Be in different applications of accelerator mass spectrometry (AMS) is well-known. In this context the half-life of ¹⁰Be has a crucial impact, and an accurate and precise determination of the half-life is a prerequisite for many of the applications of ¹⁰Be in cosmic-ray and earth science research. Recently, the value of the ¹⁰Be half-life has been the centre of much debate. In order to overcome uncertainties inherent in previous determinations, we introduced a new method of high accuracy and precision. An aliquot of our highly enriched ¹⁰Be master solution was serially diluted with increasing well-known masses of ⁹Be. We then determined the initial ¹⁰Be concentration by least square fit to the series of measurements of the resultant ¹⁰Be/⁹Be ratio. In order to minimize uncertainties because of mass bias which plague other low-energy mass spectrometric methods, we used for the first time Heavy-Ion Elastic Recoil Detection (HI-ERD) for the determination of the ¹⁰Be/⁹Be isotopic ratios, a technique which does not suffer from difficult to control mass fractionation. The specific activity of the master solution was measured by means of accurate liquid scintillation counting (LSC). The resultant combination of the ¹⁰Be concentration and activity yields a ¹⁰Be half-life of T_1/2 = 1.388 ± 0.018 (1 s, 1.30%) Ma. In a parallel but independent study (Chmeleff et al. [11]), found a value of 1.386 ± 0.016 (1.15%) Ma. Our recommended weighted mean and mean standard error for the new value for ¹⁰Be half-life based on these two independent measurements is 1.387 ± 0.012 (0.87%) Ma.