No abstract available

[en] A gamma camera system having control components operating in conjunction with a solid state detector is described. The detector is formed of a plurality of discrete components which are associated in geometrical or coordinate arrangement defining a detector matrix to derive coordinate signal outputs. These outputs are selectively filtered and summed to form coordinate channel signals and corresponding energy channel signals. A control feature of the invention regulates the noted summing and filtering performance to derive data acceptance signals which are addressed to further treating components. The latter components include coordinate and enery channel multiplexers as well as energy-responsive selective networks. A sequential control is provided for regulating the signal processing functions of the system to derive an overall imaging cycle

[en] A different high purity germanium detectors fabrication method is described. A very thin diffusion film with an abrupt change of the type conductivity are obtained. The fine diffusion layer thickness makes possibly their utilization in experimental systems in which all the data are elaborated directly on the computer

[en] Vano et al.'s empirical relation has been proved to be valid for HPGe detectors with large active volume range. New values of a and b are 0.6246 and -2.136 respectively. The slope of the efficiency curve is charcteristic of detectors and independent of the geometry conditions within 2% error. It can be calculated within an error less than 3% in a certain energy range. (orig.)

[en] The average fluence rate F as a function of source to detector-centre distance D+L/2 for several detector volumes V, detector radii R and detector lengths L for unattenuated radiation incident on the flat face of cylindrical detector has been determined by the numerical integration method. It is shown that: (1) for a small value of D+L/2 , and (i) keeping the value of R constant, F increases with L (or V), (ii) keeping the value of L constant, F decreases when R increases (or V), (iii) for equal value of V, F increases when both R decreases and L increases, (iv) when either V increases or remains constant, F increases with L, and (v) when V increases, F does not necessarily increase, as explained in (i) and (ii) above, (2) when D+L/2 increases, F decreases for a particular value of V, (3) when D+L/2 is large (* 1000 mm), F converges to a single value for any volume. Suggestion for the determination of F for attenuated radiation is given

No abstract available

[en] Improved radiological measurement sensitivity can be attained by either increasing the count rate or reducing the background. In many required scenarios it is not possible to increase the sample size, the concentrations of radioactivities, or the efficiency of the detector. In such cases the only possibility for improving the sensitivity is a significant reduction in background. This presentation describes the current state-of-the-art technology in our ongoing background reduction efforts which have resulted in background levels five orders of magnitude lower than the best laboratory spectrometers of a few years ago. The fabrication of two 1.1 kg germanium detectors from electroformed copper hardware components and specially deep-mined germanium ore are discussed. The installation and operation of these and similar detectors in the Homestake Gold Mine and the Sudan Mine is described. An above ground laboratory version of these spectrometers is discussed. Plans for the last step in germanium spectrometer background reduction--fabrication of the germanium crystals from isotopically enriched material is also given

[en] In this study, a multipurpose ERS system equipped with two LaBr3(Ce) detectors was developed to utilize to the ground based gamma-ray spectrometry using a tripod as well as mobile gamma-ray spectrometry using a backpack, carborne, and airborne survey. The purpose of this system is to efficiently integrate a large number of comprehensive survey results with the consistency, so that it can reduce the uncertainty induced from the different survey platforms in the case of integrating diverse survey results. To simultaneously determine the dose rate and radioactivity in the environment using a developed multipurpose ERS system, the dose rate spectroscopy was applied to this system through the Monte Carlo simulations. Two information, that is, dose rate and radioactivity, can be achieved from the ground based gamma-ray spectrometry using a tripod. On the other hand, only dose rate is generally evaluated in the mobile survey, such as backpack, carborne, and airborne gamma-ray spectrometry. Finally, the feasibility of developed multipurpose ERS system was experimentally verified in the well-characterized site using a portable HPGe detector, as assessing the radioactivity concentration in the ground and its dose rate at 1 m above the ground by the nuclide. A multipurpose ERS system based on two units of a 2^φx2 LaBr3(Ce) detector was developed to utilize to the ground based gamma-ray spectrometry using a tripod as well as mobile gamma-ray spectrometry using a backpack, carborne, and airborne survey. This system can make a simultaneous determination of dose rate and radioactivity by applying the dose rate spectroscopy.

[en] The LabSOCS software was used to optimise the geometric dimensions of cylindrical containers and improve the detection efficiency of a high-purity germanium detector for the measurement of environmental radioactivity samples. The optimum ratio of diameter and height for different sample volumes were determined. In addition, the degrees of influence of the sample volume and density when the amount of sample was fixed were compared. Results show that the effect of sample volume on detection efficiency was significantly greater than that of sample density for a given sample amount. (author)

No abstract available