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Abstract: We report the scintillation luminosities, decay times, and emission wavelengths for 19 Ce3+ activated scintillators, 18 Eu2+ activated scintillators, and 4 self-activated scintillators. Of these, 18 have not been previously reported either as phosphors or scintillators. Their luminosities range from 40,000 to under 1000photons/MeV. While these scintillators may not have properties that make them top candidates for widespread use, their data will contribute to a deeper understanding of factors that limit scintillator performance. [Copyright &y& Elsevier]

Abstract: In this paper we discuss two novel methods of measuring afterglow in scintillators. One method is designed for X-ray detection and the other for neutron detection applications. In the first method a commercial fan-beam scanner of basic design similar to those seen at airports is used to deliver a typically 12ms long X-ray pulse to a scintillator by passing the test equipment through the scanner on the conveyor belt. In the second method the thermal neutron beam from a research reactor is incident on the scintillator. The beam is cut-off in about 1ms using a 10B impregnated aluminum pneumatic shutter, and the afterglow is recorded on a dual range storage oscilloscope to capture both the steady state intensity and the weak decay. We describe these measurement methods and the results obtained for a range of developmental ceramic and glass scintillators, as well as some standard scintillators such as NaI(Tl), LiI(Eu) and the plastic scintillator NE102A. Preliminary modeling of the afterglow is presented. [Copyright &y& Elsevier]

Abstract: For a multi-layer depth-of-interaction (DOI) detector using different decay times, pulse shape analysis based on two different integration times is often used to distinguish scintillators in DOI direction. This method measures a partial integration and a full integration, and calculates the ratio of these two to obtain the pulse shape distribution. The full integration time is usually set to integrate full width of the scintillation pulse. However, the optimum partial integration time is not obvious for obtaining the best separation of the pulse shape distribution. To make it clear, a theoretical analysis and experiments were conducted for pulse shape analysis by changing the partial integration time using a scintillation detector of GSOs with different amount of Ce. A scintillation detector with 1-in. round photomultiplier tube (PMT) optically coupled GSO of 1.5mol% (decay time: 35ns) and that of 0.5mol% (decay time: 60ns) was used for the experiments. The signal from PMT was digitally integrated with partial (50–150ns) and full (160ns) integration times and ratio of these two was calculated to obtain the pulse shape distribution. In the theoretical analysis, partial integration time of 50ns showed largest distance between two peaks of the pulse shape distribution. In the experiments, it showed maximum at 70–80ns of partial integration time. The peak to valley ratio showed the maximum at 120–130ns. Because the separation of two peaks is determined by the peak to valley ratio, we conclude the optimum partial integration time for these combinations of GSOs is around 120–130ns, relatively longer than the expected value. [Copyright &y& Elsevier]

Abstract: In the framework of an assessment of lanthanum halide scintillators, such as LaBr3:Ce and LaCl3:Ce on their suitability for space based gamma-ray spectroscopy, proton induced activation of the materials has been studied. One inch scintillators were subjected to proton irradiations in the range of 60–184MeV, where after the activation was measured. The activation was analyzed by identifying the decaying isotopes by means of gamma-ray spectroscopy and lifetime measurements using both a germanium detector and the activated scintillator itself. It was found that the dominant source of activation in the scintillators originates from the lighter elements in the materials: bromide and chloride, respectively. The activation of LaBr3:Ce manifest itself through gamma-decay, which partly leaves the volume. Activation of LaCl3:Ce originates mainly from beta decay, which is confined to the volume itself. [Copyright &y& Elsevier]

Abstract: We report upon the performance of an analog hadron calorimeter prototype, where plastic scintillator tiles are read out with wavelength-shifting fibers coupled to avalanche photodiodes. This prototype configuration has been tested using a positron beam at DESY with energies between 1 and 6GeV. We present different detector calibration methods, show measurements for noise, linearity, and energy resolution and discuss gain monitoring with an LED system. The results are in good agreement with our simulation studies and previous measurements using silicon photomultiplier readout. [Copyright &y& Elsevier]

We have developed a new photomultiplier tube (PMT) with high sensitivity for a wavelength-shifter fiber readout of plastic scintillators. Improvements of the photoelectron yield were made on a 2-in. PMT (Hamamatsu R329) by adopting (1) a prism-shaped photocathode, (2) an extended-green photocathode material, and (3) an optical mirror surface of the electrodes. As a result, the number of photoelectrons obtained by the new PMT has increased to be 1.8-times that by R329. Other PMT characteristics, such as uniformity of sensitivity, time response and darkcurrent are not so much different from those of R329 for practical applications. [Copyright &y& Elsevier]