No abstract available

[en] This has the accumulation effect of radiation energy and is mainly used as the element for thermoluminescent type radiation dosimeters. It has as the principal constituent a phosphor consisting of calcium sulfate as the principal constituent and other impurity elements such as dysprosium, thulium and the like. It is more sensitive by the order of 1 to 2 or more figures than the conventional ones and is excellent in the retention of absorbed radiation energy. (U.S.)

No abstract available

[en] A new method is described which can be used to determine the setting times of small amounts of high value bone cements. The test was developed to measure how the setting times of a commercially available synthetic calcium sulfate cement (Stimulan, Biocomposites, UK) in two forms (standard and Rapid Cure) varies with the addition of clinically relevant antibiotics. The importance of being able to accurately quantify these setting times is discussed. The results demonstrate that this new method, which is shown to correlate to the Vicat needle, gives reliable and repeatable data with additional benefits expressed in the article. The majority of antibiotics mixed were found to retard the setting reaction of the calcium sulfate cement. (paper)

[en] In order to develop TL dosimeter based on thinner CaSO_4: Dy Teflon discs for personnel monitoring, phosphor to Teflon proportion for 0.4 mm thick disc is optimised in this study. It takes about 100 seconds to complete the readout of a dosimeter in present TLD system based on 0.8 mm thick CaSO_4:Dy Teflon discs (phosphor to Teflon proportion of 25%-75%). It is important to achieve faster processing and prompt reporting of personal doses to have effective control on individual exposure and radiological conditions in workplaces. TLD discs of reduced thickness offer reduction in the readout time as well as improved performance for dosimetry of low penetrating radiations like beta and low energy X-rays. However, overall sensitivity decreases with the reduction in thickness for a given phosphor proportion. Earlier studies, on thin TLD discs/tape had limited success due to use of contact heating and anti buckling device. The present study is conducted using 0.4 mm thick discs of various phosphor proportions by taking readout with the N_2 gas heating for optimising the phosphor proportion for personnel monitoring

[en] Luminescence dosimetry theory and applications is a compilation of a series of lectures. Chapter 1 shows an outline of the methods currently used for dosimetry in the diverse areas of application, emphasizing the importance of the luminescence methods. Chapter 2 summarizes the general aspects of the thermoluminescence (TL) phenomenon and describes, at the same time, the application of the TL dosimetry in different fields of science. The cavity theory and its application to TL dosimetry are presented in chapter 3. The determination of TL parameters and the description of the theoretical bases of the TL process are presented in chapter 4; the requirements of personnel monitoring performance specifications, requirements of the TL material, and personal dosimetry systems are discussed in chapter 5. Performance test for TL dosimeters used in radiation protection and test methods developed by the author are described in chapter 6; in chapter 7, the author outlines a method for determining simultaneously the dose and elapsed time since irradiation using TL dosimeters ; the application in accidental exposure is also discussed. TL materials, especially with those developed by the author at the Instituto Nacional de Investigaciones Nucleares (ININ). The problems associated with neutron dosimetry are analized in chapter 9, as a solution of the problems related to fast neutron dosimetry . Lyoluminescence dosimetry (LLD) principles and application are describes in chapter 10; including modification of a TL analyzer to be used as a LL reader; finally, a brief report regarding the development of TL dosimetry in Mexico is presented in chapter 11

[en] A sensitive CaSO₄: Dy (Tm) bulb dosemeter was developed. The minimal detectable dose is 1 μGy and the dose response curve is linear up to 10 Gy. The background due to self irradiation from the ⁴⁰K content of the glass tube of the bulb and the fading is low. The bulb dosemeter shows a good resistance against mechanical burden. Owing to the above properties, the nuw bulb dosemeter proves to be particularly useful in space dosimetry, personal dosimetry and environmental monitoring. (Author)

[en] An automatic access control system has been developed using CaSO₄: Tm dosimeters and magnetic ID cards. The system is mainly composed of terminal sets each of which consists of an access-gate and an access-controller with a TLD reader. The process time is about sec on entering and 40Sec on leaving

[en] CaSO₄ phosphors activated with Smsup(3+) impurity in varying concentrations have been prepared and their electroluminescence systematically studied. The voltage and frequency dependence of brightness is discussed and conclusions are drawn regarding the possible mechanism involved in the process. (author)

[en] The CaSO₄ : Tm - PTFE TLDs have been prepared and their energy dependences of TL intensity to X-rays have been investigated. The dose dependence of the prepared CaSO₄ : Tm - PTFE TLDs is linear within the range of 100 μ Gy-10Gy for X-rays and gamma rays. The spectral peaks of TL emission spectrum are at about 350nm and 475nm. The fading rate of the main peak has been found to be about 2% for 30 days when CaSO₄ : Tm-PTFE TLDs stored in the dark room at room temperature. The energy dependence of CaSO₄ : Tm - PTFE TLD has been compensated by combining the TL responses of one bare TLD and five TLDs filtered with 1.0mm AI, 0.2mm Cu, 0.5mm Cu, 1.5mm Cu, 2.0mm Pb respectively. The determined correction coefficients for filter combination are a₀ = 0.078, a₁ = -0.009, a₂ = -0.235, a₃ = 0.588, a₄ 0.568 and a₅ = 0.180 respectively. From the results of these studies, the prepared TLD badge of six dosimeter combination may be useful as a radiation dosimeter for personal and environmental monitoring