To study the new type of dosimeter with a dose up to the ultra-high dose range of MGy, the electron spin resonance (ESR) method is used to measure the signal intensity of the sample irradiated by gamma rays or electron beams. Preliminary studies have been carried out through the selection of sensitive materials, linearity after irradiation, and stability. The results showed that the quartz can be used as a raw material for ultra-high dosimeters. After 15 min 300 ℃ proper heat treatment, the signal intensity of the irradiated quartz sample can maintain good stability within one year with a change of less than 3%. The radiation dose and the E′ signal intensity of quartz are proportional to the dose range of 10-103 kGy. The fitting coefficient is above 0.99. Compared with the high-purity quartz sample without heat treatment, the stability and R2 of fitting function of quartz sample are significantly improved. Therefore, the quartz dosimeter is suitable as a working dosimeter in the ultra-high dose range.

A set of dosimetry system with graphite ionization chamber for low energy proton beams was set up.The characteristics of self-developed graphite ionization chamber were studied.The results show that the self-developed graphite ionization chamber meets the requirement of standard ionization chamber.Transmission ionization chamber was designed and used to monitor the change of proton beams online,which increased the accuracy of results when calibrating the other dosimetry systems.Absorbed dose of low energy proton was measured by using self-developed dosimetry system with ionization chamber,and the composed standard uncertainty is 4%.The calibration method of alanine dosimeter was researched in the HI-13 Tandem Accelerator,and the RE specific values were obtained for the different proton energy.

In the experiment using Faraday cup to calibrate absorbed dose of proton in alanine dosimeter, it is necessary to consider the influence of pipes, wall and other matters. To improve the accuracy of measurement, FLUKA Monte Carlo software was employed to simulate proton transport in pipes. Simulation results prove that alanine dosimeters can be irradiated uniformly if proton beam is passed through the Ta scatter film. The actual number of proton passed through alanine dosimeter is a little greater than determination by the Faraday cup. Modifying factor is gained which is 1.014. Proton energy spectrum distribution was simulated. And the average collision stopping power of proton in alanine dosimeter was calculated subsequently. Through simulation and modification, more accuracy experiment data were gained. The calibration curve of alanine dosimeter irradiated by proton was obtained at last. The linear coefficient is 0.9995.

The nylon was used as the matrix of radiochromic film dosimeters,while hexahydroxyethyl pararosaniline cyanide(HPR-CN) was used as the dyes of radiochromic film dosimeters,and the radiochromic film dosimeter was developed.The principle,formula,characteristics and dosimetric test results of the radiochromic film dosimeters were described.The characteristics of homemade dosimeter was compared with that of FWT-60,and the homemade radiochromic film dosimeters have good dosimetry characteristics.

The design principle,structural parameter and basic characteristics of a kind of versatile current mode multi-anode gas ionization chamber which can detect the energy lost in free air and analyze the characteristic of proton beam were described.During the designing and making,the main parameters are thoroughly demonstrated through computer simulating and calculating.Tentative result indicates that the ionization chamber has perfect saturation characteristic.

Alanine dosimetry is now well established both as a reference and routine dosemeter for industrial irradiation processing. Accurate dosimetry under the relatively harsh conditions of industrial processing requires a characterisation of the parameters that influence the dosemeter response. The temperature of the dosemeter during irradiation is a difficult quantity to measure so that the accuracy of the temperature coefficient that governs the dosemeter response becomes a critical factor. Numerous publications have reported temperature coefficients for several types of alanine dosemeters. The observed differences in the measured values were commonly attributed to the differences in the polymer binder or the experimental design of the measurement. However, the data demonstrated a consistent difference in the temperature coefficients between l-alanine and dl-alanine. Since there were no commonalities in the dosemeter composition or the measurement methods applied, a clear conclusion is not possible. To resolve this issue, the two isomeric forms of alanine dosemeters were prepared and irradiated in an identical manner. The results indicated that the dl-alanine temperature coefficient is more than 50% higher than the l-alanine temperature coefficient.

Thin film alanine-PE dosimeter developed at CIAE is expected to be used as transfer dosimetry system particularly for electron beam dose measurement. Its basic dosimetry characteristics were studied under 60Co γ-ray and electron beam irradiation. The investigated dose range was between 20 and 3×105Gy. The background dose for the unirradiated dosimeter was about 4Gy. The inter-specimen scattering among 10 replicate irradiated dosimeters was less than 0.6% (1σ) for the doses of 1kGy after correction of weight differences of dosimeters. The ratio of EPR signals from two batches was about 1.0091±0.0049 (1σ) for 15 dose points from 70 to 40kGy. No significant dose response dependent on energy or dose rate was found in both γ-ray irradiation (average energy 1.25MeV, dose rate down to 0.4Gy/s) and electron beams irradiation (energy up to 14MeV, dose rate to 108Gy/s). The irradiation temperature coefficient was about 0.26%/°C between 15 and 50°C in the dose range from 5 to 50kGy. Another important feature, post-irradiation stability, was also studied in detail for dosimeters stored at 4°C, room temperature and 40°C with relative humidity of 98%, 76%, 58%, 33% and 12%. Uncertainty of the dosimetry system for electron beam dose measurement was 2.9% (k=2) for dose from 102 to 104Gy, while 5.6% (k=2) for dose higher than 104Gy. The preliminary inter-comparison results between CIAE alanine-PE/EPR dosimetry system and the reference dosimetry systems from RISO, JAERI and INCT were comparable within their combined uncertainty, which showed the potential of CIAE alanine-PE/EPR dosimetry system to be used as transfer dosimetry system.

In ESR dating, the age is given by the ratio of paleo-dose to annual dose. Generally, the paleo-dose is obtained by linear extrapolation in regeneration or additional irradiation method. Therefore, dose determination in manual irradiation becomes one of the important factors that effect reliability of the dating results. Usually, there are two ways to determine the dose of manual irradiation: one is called dose rate method, which calibrates the dose rate of the position by standard dosimeter before dating sample irradiation at the same position. Dose will be determined by the dose rate and irradiation time of the sample. In this method, Fricke dosimeter is usually used as standard dosimeter; the other is called concomitant method, which puts reference dosimeter together with the dating sample to the position before irradiation. They will be irradiated simultaneously and the dose will be given by the reference dosimeter. In this method, alanine dosimeter is generally used as the reference dosimeter. In the paper, these two methods are discussed. Two types of alanine dosimeter are used as reference dosimeters: one is pellet alanine dosimeter, the other is alanine film dosimeter. We use dose rate results that were calibrated one year ago to evaluate the current dose rates. Irradiation time is determined according to the nominal dose and the dose rate. However, the actual dose was determined by the alanine dosimeter that was irradiated with the dating sample together. Since it is not practical to calibrate the dose rate every time for every position before dating sample irradiation, the concomitant method that uses alanine dosimeter as reference to be irradiated with the dating sample together will be more practical and reliable compared with the dose rate method.

老于20万年的碎屑沉积物的绝对测年方法急待建立.本文利用我国典型的碎屑沉积物--洛川黄土石英中的Al心,在115 K温度下进行ESR测年研究,初步给出了4层黄土剖面的古剂量值.结果表明,古剂量值随着地层深度的增加而呈增长趋势,说明利用ESR方法测定低温Al心可获得老于20万年的碎屑沉积物的地质年龄.