Gamma sensitivity of ionization chambers

Translated from Atomnaya Énergiya, Vol. 66, No. 6, pp. 421–423, June, 1989.     

Modulated-signal ionization chambers for monitoring nuclear reactors

All-Union Scientific Research Institute. Translated from Atomnaya Énergiya, Vol. 73, No. 5, pp. 404–406, November, 1992.     

软X射线电离室的制作及性能测试

本文论述了我们用各种材料制作的一系列用于软X射线剂量测量的薄窗薄壁电离室,形状有圆柱形和球形两种。通过实验测得的这些电离室的角度响应、能量响应等性能,证明它们优于目前国内外软X射线剂量仪器电离室探头的性能。     

高气压大型电离室的制作和性能测试

叙述了两种电离室的制作,测量了饱和特性、轴向均匀性、灵敏度、稳定性等性能参数以及物料对~(137)Csγ射线的吸收规律。     

Remote calibration of ionization chambers for radioactivity calibration

A new calibration technique, referred to as e-trace, has been developed by the National Institute of Advanced Industrial Science and Technology (AIST). The e-trace technique enables rapid remote calibration of measurement equipment and requires minimal resources. We calibrated radioisotope calibrators of the Japan Radioisotope Association (JRIA) and the Nishina Memorial Cyclotron Center (NMCC) remotely and confirmed that remote calibration provided results that are consistent with the results obtained by existing methods within the limits of uncertainty. Accordingly, e-trace has been approved as the standard calibration method at AIST. We intend to apply remote calibration to radioisotope calibrators in hospitals and isotope facilities.     

Investigation of the phonon current in neutron ionization chambers

Conclusions Investigations of the phton current in neutron ionization chambers have shown that the main contribution stems from positive ions. Investigations made with the mass spectrometric technique to determine the composition of those ions have led to the conclusion that a significant portion of the ions emitted from a surface which had been heated for 5 h are hydrocarbon ions. This is a consequence of the ionization of the molecules of the material of which the residue of the binder is composed. Prolonged heating (25 h) makes it possible to eliminate hydrocarbon lines from the mass spectrum. However, the spectrum still comprises lines resulting from the current of the K⁺ ions which determine the lower limit of the phonon current in neutron chambers.Translated from Atomnaya Énergiya, Vol. 48, No. 6, pp. 391–392, June, 1980.     

Low-level measurements of Ra-226/Rn-222 by pulse ionization chambers

Characteristics of two ionization chambers have been studied and the chambers utilized for ²²⁶Ra/²²²Rn measurements for more than ten years. The results obtained show that coating of internal surfaces with a pure and thin Ag-layer enhances the background of ionization chambers in spite of some improvements at the early stages of operation. In addition to previously known parameters influencing the accuracy in routine measurements, new correction factors are suggested. 226Ra impurities in the body of ionization chambers are found to act not only as a permanent, but also as a temperature-dependent source of background. Earlier accuracies of ²²⁶Ra/²²²Rn measurements have been considerably improved by assuring long-term mechanical and thermal stability of the ionization chambers.     

采用电离室测定重离子束的Bragg峰位

从探索定点定位诱变要求出发，提出了重离子束Ｂｒａｇｇ峰可作为一个有用手段，阐述了测量重离子束Ｂｒａｇｇ峰的原理和实验装置，采用一对电离室测定初始能量为５０ＭｅＶ／ｕ左右＾１４Ｎ＾７＋离子束在物质密度归一到小麦材料后的Ｂｒａｇｇ峰位。最终得到峰位深度约为４．８５ｎｍ，离子束的最大射程为５．５ｍｍ左右。     

Measurement of boron isotopes by negative thermal ionization mass spectrometry

The isobaric interference for boron isotopic measurement by negative thermal ionization mass spectrometry (NTIMS) has been studied,The result shows that the CNO^- is not only from the organic material,but also from nitrate in loading reagent in NTIMS,Monitoring the mass 43 ion intensity and 43/42 ratio of blank are also necessaary fro the boron isotopic measurement by NTIMS,other than is only boron content.     

Proton energy determination using activated yttrium foils and ionization chambers for activity assay

Excitation functions of the ⁸⁹Y(p, xn) nuclear reactions were measured up to 18 MeV by the conventional activation method using the stacked-foil technique, and the irradiation of single foils. Activity assays of the irradiated foils were performed via ionization chamber and gamma spectroscopy methods. Activity ratios of the activation products were measured in two different facilities and evaluated for use as a practical and simple method for proton energy determinations. Cross section values measured in this work were compared with published data and with theoretical values as determined by the nuclear reaction model code EMPIRE II. In general, there was a good agreement between the experimental and theoretical values of the cross section data. Activity ratios of the isomeric and ground state of ⁸⁹Zr measured via ionization chamber were found to be useful for proton energy determinations in the energy range from 7 to 15 MeV. Proton energies above 13 MeV were accurately determined using the ^89gZr/⁸⁸Zr and ^89gZr/⁸⁸Y activity ratios measured via gamma spectroscopy.     

Boron-coated gas-filled ionization chambers for measuring the neutron flux density in a reactor

TFA. Translated from Atomnaya Énergiya, Vol. 74, No. 5, pp. 454–456, May, 1993.     

Burnup characteristics and performance of boron nitride and boron coated urania and urania-gadolinia fuels

In this research the burnup performance of (1) boron nitride (BN) and (2) boron nitride-boron (B), hybrid coated urania (UO₂) and urania-gadolinia (Gd₂O₃) fuels were studied. The behavior of fuel burnup, depletion of BN and B, the effect of coating thickness and also Gd₂O₃ content on the burnup performances of the fuels were found by using the code WIMS-D/5 for pressurized water reactor (PWR) and boiling water reactor (BWR) fuel assemblies. The optimum thickness ratio of B to BN was found as 4 and their thicknesses were chosen as 4 and 1 μm, respectively. Based on this observation, calculations were performed for the standard fuel assemblies with and without burnable poison and similar assemblies with BN-B hybrid coating with the desired BN-B thicknesses. Results are discussed to make an assessment of the effect of such hybrid coating on fuel cycle characteristics.