[en] It is shown that improvements of the detector acceptances (in solid angle and momentum bite) is as important as increased duty cycle for coincidence experiments. To have a maximum efficiency and thus to reduce the cost of experiments, it is imperative to develop maximum solid angle systems. This implies an axial symmetry with respect to the incoming beam. At Saclay, we have investigated some of the properties of specific detectors covering up to 90% of 4π steradians for a high energy, 100% duty cycle electron accelerator. The techniques of wide angle spectrometers have already been explored on a large scale in high energy physics. However, in the case of charged particles, such detectors, compared to classical iron dipole spectrometers, present a smaller resolving power and a rather low background rejection. The choice of which of these two solutions is to be used depends on the conditions of the specific experiment

No abstract available

[en] The effect of the potential different at the focusing chamber electrodes of the FEU-85, FEU-87, and FEU-93 photomultipliers on the intensity of afterpulses resulting from gas discharge processes is investigated. With appropriately selected potentials, the number of recorded secondary pulses can be decreased. Charge distribution spectra are obtained for this sort of pulses, which gives a qualitative estimate of both the homogeneity of the charge and mass distribution of residual gases and the ion-electron emission coefficients

[en] The effect of the potential difference at the focusing chamber electrodes of the XP2020, FEU-85, FEU-87, and FEU-93 photomultipliers on the intensity of afterpulses resulting from gas discharge processes is investigated. The time distribution of the afterpulses in the metal channel PMTs - H6780 and R7600U-200 - is studied as well

[en] A laboratory exercise for calculation of true coincidence summing correction factors as well as calculating the effect of deviations between sample and standard source (filling height) was developed. This laboratory exercise was held in a masters course in nuclear chemistry the first time during fall 2013. The aim of the exercise was to high-light the importance of correcting for biases due to different systematic effects in gamma spectrometric measurements. (author)

[en] The electronic blocks of a fast-slow coincidence spectrometer, manufactured in the Nuclear Reaction Laboratory, Nuclear Physics Department is described. The spectrometer may be used with different detectors, such as Si(Li), Ge(Li), NaI(T1) and others in coincidence, correlation and life-time measurements. The article presents the principal circuits and short description of the block, together with their main characteristics and some recommendations for their adjustment

[en] A method for subtracting background from triple-coincidence γ events is presented. In our data set it was used to remove 40% of the noise without affecting photopeaks with intensity of >18 counts. An example of performance of Ward's clustering algorithm applied to three-dimensional photopeak searching is also presented. Several standard clustering algorithms were found to be applicable only to background-subtracted data. (orig.)

[en] The spectrum obtained with a coindicence-and-addition gamma-ray spectrometer is free of background, photopeaks, Compton distributions and fortuitous addition peaks, and it is possible to distinguish the addition peaks corresponding to levels. Some new gamma rays observed in the decay of sup(110m)Ag by usual γ-ray spectroscopy are reported

No abstract available

No abstract available