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[en] Fluctuations and accuracy are analysed for digital ratemeters when the floating mean value algorithms are applied. The statistical nature of signal pulse train is taken into account, and relevant relations are derived. 5 refs., 3 figs. (Author)

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[en] Microprocessor, as an electronic component, combined with memories has a great software versatility and is able to handle a large quantity of data. When it is used in measurement instrumentation new qualities may appear, and here are analysed possible consequences when microprocessor is introduced in radiological instrumentation. The role of a microprocessor strongly depends on the purpose of the instrument. Due to that reason we devide all radiological instruments into three classes: general purpose instruments, special instrumentation and measuring systems. For every of these classes the place and tasks of a microprocessor is discussed in detail. Some solutions are reviewed, peculiar features due to microprocessor are underlined, but solutions where the microprocessor gives a new quality in the measuring method or results were prefered. At the same time interesting possibilities are pointed out and new facilities which might appear are discussed. Particular aspects of microprocessor application in radiological instrumentation are discussed: the influence on measuring methods, accuracy, measuring possibilities, the new type of data, an new user's psychology. Consequently, the idea arises that the radiological instrumentation might be characterised in future by software support rather than by built in electronic components. (Author)

[en] Quasi exponential algorithm and three versions of linear algorithm are presented and analyzed. The response time is the parameter which is used to compare different algorithms. From this comparison follow the conclusions which algorithms are convenient or inconvenient for stationary and/or portable radiation monitors. (author)

[en] Advantages of digital rate meter, when applied in radiological protection instruments for accident conditions, re discussed. Some requirements imposed by accident conditions on such instruments are indicated. The specific properties of digital rate meters are shown and some solutions which enable realisation of defined tasks are pointed out. The behaviour of one solution is illustrated by an example simulated on the computer. (author)

[en] The problem of maintaining a low-level spectrometer free of contamination under conditions of high environmental contamination is of significant concern to monitoring laboratories. A chance to test the procedures for protecting our HP-Ge detector arose during the first stages of the Chernobyl incident. The background gamma-ray spectra of the 8% efficiency shielded low-background HP-Ge detector in the energy range of 60-2,700 keV before and after the Chernobyl accident had been investigated. In the measurement performed just the day before a radioactive cloud reached the area, the total count rate in that energy range was found to be 0.58 c.p.s. The highest rates between 0.8 and 0.9 c.p.s. were obtained 4-7 days after the accident. In the measurement from about 70 days after the accident, the rate was 0.59 c.p.s. (i.e., very close to the rate value before the accident). The presence of some 14-15 fission products have been confirmed in measurements of gamma spectra of samples taken from outside the laboratory, shortly after a radioactive cloud spread all over the country. In the background spectrum taken 70 days later, only gamma lines of three isotopes remained: ¹⁰³Ru(39.2d), ¹³⁴Cs(2.06y), and ¹³⁷Cs(30.14y). 1 ref., 1 fig. 1 tab

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[en] Low-background off-line gamma-ray spectroscopic measurements of the thin Au and thick Ta targets have been performed to determine or estimate yields of long-lived isotopes created in the following reactions: ⁷⁴Ge + ¹⁹⁷Au and ⁹³Nb + ¹⁸¹Ta. The main goal of these experiments was to investigate and compare mechanisms dominating the reactions in the two similar compound systems for a thin and thick target at approximately the same incident energy of 18 meV/u. The cumulative cross-section distribution for the formation of proton-rich, neutron-rich chains and independent isotopes in 495 μg/cm² thick Au target after bombardment with ⁷⁴Ge ions, has been determined for about 90 (T_1/2>1.5 d) nuclei. The similar cumulative cross-section distribution of about 50 (T_1/2>20 d) reaction products in 0.5 mm thick natural Ta target after bombardment with ⁹³Nb, has been determined and compared with the former one. (author)