Gy. Máthé

A METHOD FOR PULSE SHAPE DISCRIMINATION

Abstract For some detectors the rise-time of the pulses depends on the kind of particles. By electronical differentiation of the detector pulses the moment at which the differentiated pulses cross the zero level is different for unequal rise times. These differences can be measured and yield informations about the kind of the particles. A suitable apparatus for the pulse shape discrimination at multiplier pulses is described. Using CsI(Tl) crystals similar results were obtained as by other authors. With NaI(Tl) we got a separation better than for CsI(Tl). Some calculations concerning the operation of the method explain the results.

Method for the elimination of superposed pulses in nuclear spectroscopy

Abstract Superposition of a large number of small pulses produces a background in the higher energy region which is extremely difficult to calculate. By a shape discrimination, the background arising from superposition can be considerably reduced, and the intensity of the remaining background can be measured.

Experiences on the application of the sum-coincidence method

Abstract For the study of cascade γ-processes. Hoogenbooms sum-coincidence method 1 ) has proved exceedingly useful. This method has made it possible to detect transitions of very low intensity, and possesses advantages for measurements of angular correlation as well. As the authors experience shows, in the sum-coincidence spectrum, false peaks or background levels of a certain height may appear in part of the discrimination region. This is partly due to instrumental reasons, partly to the characteristics of the method itself, and it depends on the properties of the decay scheme under study.

Investigations of the decay-scheme of Fe59

Abstract We have examined the gamma-ray spectrum and gamma-gamma coincidence spectrum of Fe59 by means of scintillation spectrometers. The two lines of high energy have been found to be 1.08 and 1.27 MeV respectively. Between these lines no genuine coincidence could be detected. It was the analysis of beta spectrum and beta-gamma coincidence spectra which yielded the beta groups of 275±5 and 455±5 keV end-point energies. The intensity of these was 44.6 and 55.4% respectively, and their corresponding log ft values were 5.3 and 6.1. The relative intensity of the high energy beta transition directly into the ground state was found not to attain 0.5%.

Investigation of the decay scheme of Cr51

Abstract The energy distribution of γ-rays arising from the decay of Cr51 was investigated by the scintillation method. Besides the well-known, most intense transition of 323 keV, we also found the 323 keV and 320 keV cascade transitions of low intensity. At 150 keV a new γ-transition in cascade with the line of 323 keV was found. A cross-over transition of 470 keV energy was observed in parallel with the cascade.

Pulse-shape discrimination method for particle identification

Abstract A new electronic method for pulse shape discrimination is described, and this method was applied for identification of various charged particles. By using a single crystal scintillation spectrometer with CsI(Tl) crystal the variation of the fluorescent decay time with the alpha and proton energy is presented.

Further γ-spectroscopic investigations on the decay scheme of I131

Abstract Problematic points in the decay scheme of I131 were studied by means of the scintillation and coincidence techniques. The γ-rays at 156 and 210 keV, reported earlier, were recognized to be spurious. The long known γ-ray of 177 keV which does not fit into the decay scheme was found to be in coincidence with a new ray of 326 ± 10 keV. The intensity of this new γ-cascade is ≈ 0.2% in relation to the γ-ray of 364 keV. From the level of 500 ± 10 keV energy corresponding to the sum of the two previous rays in cascade, a cross-over transition occurs also with a relative intensity of 0.8 ± 0.2%. Furthermore it was found that in parallel with the direct transition of 364 keV only the cascade of 80-284 keV is present.

Investigations on the decay scheme of I131 in the low energy region of gamma-rays

Abstract The region below 364 keV energy of gamma radiation deriving from the decay of I131 was examined by scintillation techniques with ordinary as well as with sum-coincidence methods. A new cascade of 156–210 keV (of an intensity of ≈1 % in relation to the cross-over transition) from a level of 364 keV into the ground state was found. Furthermore the existence of the 177 keV line was confirmed by our studies.

Further gamma-spectroscopic inquiry into the decay scheme of Fe59@@@Дальнейшие γ-спектроскопические исследования схемы распада Fe59

The gamma-rays in the decay of Fe59 were examined by the sum-coincidence method. The measurements definitely confirm the existence of the 1.432 MeV level and the 143 as well as the 335 keV gamma-lines. It appears on the other hand that the 1.189, 1.458 and 1.479 MeV levels known from the (p, p’) scattering are not involved in the decay of Fe59. In the case of the 192–1097 keV cascade, the results of the preliminary angular correlation measurements differ from those reported bySchiff andMetzger.РезюмеПри распаде Fe59 γ-лучи были исследованы способом суммированных совпадений. Измерения подтверждают существования уровня 1,432 Мэв и γ-линии с энергией 143 и 335 кэв в паспаде Fe59. С другой стороны выяснено, что уровни с энергией 1,189, 1,458, 1,479 Мэк, которые известны из рассеяния (p, p’), не включены в распад Fe59. Для каскада 192–1097 кэв результаты предварительных измерений угловой корреляции отличаются от результатов, которые были опубликованы Шиффом и Метзгером.

Experimentelle Anordnungen mit A. P. M.-Prinzip für Polarisationsmessungen

ZusammenfassungDer Artikel beschreibt zwei Messanordnungen, die auf dem a. p. m. (associated particle method)-Prinzip beruhen und für Polarisationsmessungen entwickelt wurden. Durch den in Koinzidenz erfolgenden Nachweis der Neutronen und3He-Teilchen der D(d, n)3He-Reaktion ist es möglich, einen Neutronenstrahl genau definierter Energie und Richtung zu erhalten; ausserdem ist mit der Registrierung der3He-Teilchen einen einwandfreie Monitorisierung gewährleistet.РезюмеВ работе описываются два измерительных приема, которые базируются на принципе а. р. м. (метод связанных частиц) и разрабатываются для измерения поляризации. Через проявление в совпадении нейтронов и3He-частиц реакции D (d, n)3He имеется возможность получить нейтронный поток вполне определенной энергии и направления. Кроме этого, регистрацией3He-частиц обеспечивается безупречный контроль выхода нейтронов.