No abstract available

[en] The aim of this invention is to be able to determine the emerging or effective activity of the α radiation emitted by a source, by a simple and reliable method in an activity range extending from a fraction of a mCi to several Curies, by means of an electric microphone. The process and device described in the invention permit absolute as well as relative determinations of the activity of the α rays emitted by the source and also permit a measurement of the local emission of this source. Further, when the microphone includes a substance which is the seat of a reaction (n, α), the process and device under the invention allow the neutron radiation emitted by a neutron source to be determined. Specifically, the characteristic of the process is that near the source there is a microphone comprising two metal plates. The first plate of the microphone (sometimes called armature) is placed opposite the α radiation source and is of sufficiently small thickness for the α radiation emitted by the source to cross it without apprecialbe attenuation. Between these two plates, as with the usual capacitive microphone, a difference of continuous potential is established and the intensity of the α radiation emitted by the source is determined by measuring, after amplification, the potential developed between the two plates of the microphone, (this potential being created by the charges collected on these plates and which are created by the α radiation in the ionisable gas included in the volume thus delimited)

No abstract available

No abstract available

[en] A new method for the calibration of a radioactive source for liquid scintillator counting is described. The method uses, as yield variation parameter, the triple and double coincidence ratio (TDCR), the coincidence counting ratio curve is extrapolated up to TDCR = 1 and an approximate value of the sample activity is obtained directly. The paper gives the principle of the method, yield calculation and an estimate of theoretical uncertainty. Measurements for tritiated water agree with total uncertainty of ± 0.63 % of the NBS standard value

No abstract available

[en] A proposal is submitted of a standard method of expressing the results of dosimetric measurements and of inaccuracies, based on the recommendations of the British Calibration Service, Physikalisch-Technische Bundesanstalt, and the Czechoslovak Standard CSN 25 0008. Defined and discussed in detail are random, systematic and gross inaccuracies, systematic and random inaccuracies in combination, inaccuracies in calibration and routine measurements. Formulas are presented for calculations and tables are listed of inaccuracies and corrections values. (H.S.)

[en] Different codes of practice are in use or under preparation by several groups and national or international societies, concerning the dosimetry of proton beams. In spite of a large number of experiences and the increasing interest on this field, there are still large incertitudes on some of the basic conversion and correction factors to get dose values from different measuring methods. In practice, dose uniformity between centers is searched and encouraged by intercomparisons using standard procedures. We present the characteristics and the results on proton dosimetry intercomparisons using calorimeters, Faraday cups and ion chambers, as well as on the use of other detectors like diodes, radiographic films and TLD. New detectors like diamond, scintillators, radiochromic films, alanine, gels, ... can give new solutions to particular problems, provided their response is not affected at the end of the proton range (higher LET region), and their resolution, range, linearity, cost, ... are well adapted to practical situations. Some examples of special challenges are non interfering measurements during treatments for quality control, in vivo measurements, small beams for stereotactic irradiations, scanned beams and correlations between dosimetry, microdosimetry and radiobiology

[en] Gamma spectral analysis of irradiated material can be used to determine absolute disintegration rates for specific radionuclides. These data, together with measured values for the thermal and epithermal neutron fluxes, and irradiation, cooling and counting time values, are all the experimental information required to do absolute Instrumental Neutron Activation Analysis. The calculations required to go from product photon emission rate to target nuclide amount depend upon values used for the thermal neutron capture cross-section, the resonance absorption integral, the half-life and photon branching ratios. Values for these parameters were determined by irradiating and analyzing a series of elemental standards. The results of these measurements were combined with values reported by other workers to arrive at a set of recommended values for the constants. Values for 114 nuclides are listed

[en] The report briefly describes how the coincidence methods that is routinely used in nuclear spectroscopy to study complex decay and level schemes of atomic nuclei, and for the determination of absolute activity of standards for detector calibration, can also be used for the determination of the absolute detector efficiency