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BiI 3 single crystals were grown by the physical vapor transport method. The repeated sublimation of the starting material reduced impurities in the BiI 3 single crystal to sub-ppm levels. The detector was fabricated by depositing Au electrodes on both surfaces of the 100-μm-thick BiI 3 single crystal platelet. The resistivity of the BiI 3 single crystal was increased by post-annealing in an iodine atmosphere ( ρ =1.6×10 11 Ω cm). Pulse height spectroscopy measurements showed clear peaks in the energy spectrum of alpha particles or gamma rays. It was estimated that the mobility-lifetime product was μ e τ e =3.4–8.5×10 −6 cm 2 /V and the electron–hole pair creation energy was 5.8 eV. Our results show that BiI 3 single crystals are promising candidates for detectors used in radiographic imaging or gamma ray spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: Hard X-ray Imager and Soft Gamma-ray Detector are being developed as onboard instruments for the Astro-H mission, which is scheduled for launch in 2014. In both detectors, BGO scintillators play key roles in achieving high sensitivity in low Earth orbit (LEO), by generating active veto signals to reject cosmic-ray events and gamma-ray backgrounds from radio-activated detector materials. In order to maximize background rejection power, it is also important to minimize the energy threshold of this shield. As a readout sensor of weak scintillation light from a number of BGO crystals in a complicated detector system, high performance, reverse-type Avalanche Photodiodes (APDs), with an effective area of are being employed, instead of bulky photomultiplier tubes (PMTs).Another advantage of using APDs is their low power consumption, although the relatively low gain of APDs (compared to conventional PMTs) requires dedicated analog circuits for noise suppression. In this paper, we report on the development and performance of APD detectors specifically designed for the Astro-H mission. In addition to APD performance, various environmental tests, including radiation hardness and qualification thermal cycling, will be described in detail. Moreover, a dedicated charge sensitive amplifier and analog filters are newly developed and tested here to optimize the performance of APDs to activate fast veto signals within a few from the BGO trigger. We will also report on overall performance testing of a prototype BGO detector system that mimics the data acquisition system onboard Astro-H. [Copyright &y& Elsevier]

Abstract: We have studied the performance of large area avalanche photodiodes (APDs) recently developed by Hamamatsu Photonics K.K, in high-resolution X-rays and -rays detections. We show that reach-through APD can be an excellent soft X-ray detector operating at room temperature or moderately cooled environment. We obtain the best energy resolution ever achieved with APDs, 6.4% for 5.9keV X-rays, and obtain the energy threshold as low as 0.5keV measured at . Thanks to its fast timing response, signal carriers in the APD device are collected within a short time interval of 1.9ns (FWHM). This type of APDs can therefore be used as a low-energy, high-counting particle monitor onboard the forthcoming Pico-satellite Cute1.7. As a scintillation photon detector, reverse-type APDs have a good advantage of reducing the dark noise significantly. The best FWHM energy resolutions of and were obtained for 59.5 and 662keV -rays, respectively, as measured with a CsI(Tl) crystal. Combination of APDs with various other scintillators (BGO, GSO, and YAP) also showed better results than that obtained with a photomultiplier tube (PMT). These results suggest that APD could be a promising device for replacing traditional PMT usage in some applications. In particular 2-dim APD array, which we present in this paper, will be a promising device for a wide-band X-ray and -ray imaging detector in future space research and nuclear medicine. [Copyright &y& Elsevier]

The Cherenkov Telescope Array (CTA) is the next generation VHE γ-ray observatory which will improve the currently available sensitivity by a factor of 10 in the range 100 GeV to 10 TeV. The array consists of different types of telescopes, called large size telescope (LST), medium size telescope (MST) and small size telescope (SST). A LST prototype is currently being built and will be installed at the Observatorio Roque de los Muchachos, island of La Palma, Canary islands, Spain. The readout system for the LST prototype has been designed and around 300 readout boards will be produced in the coming months. In this note we describe an automated quality control system able to measure basic performance parameters and quickly identify faulty boards. [ABSTRACT FROM AUTHOR]

Abstract: Astro-H is the sixth Japanese X-ray space observatory which will be launched in 2014. Two of onboard instruments of Astro-H, Hard X-ray Imager and Soft Gamma-ray Detector are surrounded by many number of large Bismuth Germanate (Bi4Ge3O12; BGO) scintillators. Optimum readout system of scintillation lights from these BGOs are essential to reduce the background signals and achieve high performance for main detectors because most of gamma-rays from out of field-of-view of main detectors or radio-isotopes produced inside them due to activation can be eliminated by anti-coincidence technique using BGO signals. We apply Avalanche Photo Diode (APD) for light sensor of these BGO detectors since their compactness and high quantum efficiency make it easy to design such large number of BGO detector system. For signal processing from APDs, digital filter and other trigger logics on the Field-Programmable Gate Array (FPGA) is used instead of discrete analog circuits due to limitation of circuit implementation area on spacecraft. For efficient observations, we have to achieve as low threshold of anti-coincidence signal as possible by utilizing the digital filtering. In addition, such anti-coincident signals should be sent to the main detector within to make it in time to veto the A–D conversion. Considering this requirement and constraint from logic size of FPGA, we adopt two types of filter, 8 delay taps filter with only 2 bit precision coefficient and 16 delay taps filter with 8 bit precision coefficient. The data after former simple filter provides anti-coincidence signal quickly in orbit, and the latter filter is used for detail analysis after the data is down-linked. [Copyright &y& Elsevier]

Abstract: A scanning magnet using high-temperature superconductor (HTS) wire was designed, built, and tested for its suitability as a beam scanner. After successful cooling tests, the magnet performance was studied using DC and AC currents. With DC current the magnet was successfully operated to generate designed field distributions and effective length. In AC mode, the magnet was operated at frequencies of 30–59Hz and a temperature of 77K as well as 10–20Hz and 20K. The power losses dissipated in the coils were measured and compared with the model calculations. The observed losses per cycle were independent of the frequency and the scaling law of the transport current was consistent with theoretical predictions for hysteretic losses in HTS wires. [Copyright &y& Elsevier]

Abstract: The lineshapes and peak position of Doppler corrected spectra from in-beam experiments at relativistic energies are investigated with respect to the intrinsic energy resolution of the employed detectors, the particles’ velocities, and the photons’ emission angle uncertainties at the moment of emission. The uncertainties in velocity and photon emission angle are dependent on the lifetime of the excited state. The impact of these two observables on the lineshape and energy resolution are studied for the RISING by means of simulations and experimental results from a two-step fragmentation experiment at . Potential use of the distinct lineshape for lifetime determination is demonstrated for measured transitions. [Copyright &y& Elsevier]

Abstract: Measurements of inelastic proton scattering with high energy resolution at forward scattering angles including are described. High-resolution halo-free beams were accelerated by the cyclotron complex at the Research Center for Nuclear Physics. Instrumental background events were minimized using the high-quality beam. The remaining instrumental background events were eliminated by applying a background subtraction method. As a result, clean spectra were obtained even for a heavy target nucleus such as . A high energy resolution of 20keV (FWHM) and a scattering angle resolution of were achieved at an incident proton energy of 295MeV. [Copyright &y& Elsevier]

Abstract: Since regulation of water content of the dried fish is an important factor for the quality of the fish, water-losing process during drying (squid and Japanese horse mackerel) was analyzed through neutron beam imaging. The neutron image showed that around the shoulder of mackerel, there was a part where water content was liable to maintain high during drying. To analyze water-losing process more in detail, spatial image was produced. From the images, it was clearly indicated that the decrease of water content was regulated around the shoulder part. It was suggested that to prevent deterioration around the shoulder part of the dried fish is an important factor to keep quality of the dried fish in the storage. [Copyright &y& Elsevier]

Abstract: The C()B[2] reaction at 0 has been proposed as a new tool to calibrate the deuteron beam polarization at intermediate energies. The absolute values of the deuteron polarizations were extracted for the first time by using this reaction at 270 and 140MeV deuteron energies. The analyzing powers for the –p elastic scattering, which is used as a secondary reaction of a polarimetry, were determined by the new method. [Copyright &y& Elsevier]

Abstract: The Cute-1.7 was launched successfully in February 2006 as a piggyback satellite of the Astro-F mission. The Cute-1.7 dimensions are box with a total mass of 3.6kg. It is the second pico-satellite to have been developed completely by students of the Tokyo Institute of Technology (Tokyo Tech.) after the successful launch of the CUTE-I in June 2003. The goals of the Cute-1.7 mission are two-fold: (1) to validate high-performance, commercially available products for the first time in space. We particularly use personal digital assistants (PDAs) as a main computer in orbit (2) to demonstrate new potential uses for small satellites in various space studies, as proposed by the “satellite-core” concept. For the Cute-1.7 mission, we will carry avalanche photo diodes (APDs) as a high-count particle monitor in low-Earth orbit. Here we present details of various ground tests and pre-flight performance of the Cute-1.7 immediately before the launch. Results of the Cute-1.7 mission will provide quick feedback for space applications of APDs in Japan''s future X-ray astronomy mission NeXT. [Copyright &y& Elsevier]

Abstract: Avalanche photodiodes (APDs) are a promising light sensor for various fields of experimental physics. It has been argued, however, that variation of APD gain with temperature could be a serious problem preventing APDs from replacing traditional photomultiplier tubes (PMTs) in some applications. Here we develop an active gain-control system to keep the APD gain stable under moderate temperature variations. As a performance demonstration of the proposed system, we have tested the response of a scintillation photon detector consisting of a reverse-type APD optically coupled with a CsI(Tl) crystal. We show that the APD gain was successfully controlled under a temperature variation of , within a time-cycle of 6000s. The best FWHM energy resolution of was obtained for 662keV -rays, and the energy threshold was as low as 6.5keV, by integrating data from – cycles. The corresponding values for – cycles were and 5.2keV, respectively. These results are comparable, or only slightly worse than that obtained at a fixed temperature. Our results suggest new potential uses for APDs in various space researches and nuclear physics. As examples, we briefly introduce the NeXT and Cute-1.7 satellite missions that will carry the APDs as scientific instruments for the first time. [Copyright &y& Elsevier]

Abstract: The performance of the large area reach-through avalanche photodiode (APD), manufactured by Hamamatsu Photonics, K.K. as a high resolution X-ray detector is presented. The mentioned APD has an area of 3mm , a fast time response for signal carrier collection and its thick depletion layer of shows a potential to be used as an effective X-ray absorber below 20keV. Having a capacitance of and a low dark current of 5nA for a gain of 15, at room temperature, this APD had demonstrated one of the best energy resolutions within this kind of devices: 6.4% (FWHM) for 5.9keV photons with a minimum detectable energy of 0.3keV, measured at . The experiments for the timing property were made in a synchrotron beam facility using an 8keV X-ray beam; the reached count rate was above counts/s, corresponding to a very short dead time of 4.5ns/pulse. In order to test the radiation hardness of the APD, the device was irradiated at a Ring Cyclotron Facility with a 53.5MeV proton beam. The total dose was of 11.3krad and no fatal damage was found in the APD, although the dark current of the APD had shown an increase of one order of magnitude. Finally, the obtained results allow us to affirm that the reach-through APD has the potential to become an excellent X-ray detector, especially in the space mission application. [Copyright &y& Elsevier]

Abstract: The neutron response functions of 12.7cm diameter by 12.7cm long NE213 organic liquid scintillator have been measured in the energy range up to 390MeV at the Research Center for Nuclear Physics (RCNP) of Osaka University. The continuous energy neutrons were produced by the 392MeV proton bombardment on a 20-cm thick aluminum target and the response functions of the time-of-flight (TOF)-gated monoenergetic neutrons in a wide energy range up to 390MeV were simultaneously measured. The quasi-monoenergetic neutrons were also produced via 7Li(p,n)7Be reaction by the 392-MeV proton beam bombardment on a 1.0-cm thick 7Li target, and the TOF-gated 388-MeV peak neutrons were used to obtain the response function at this energy. The measured results show that the response functions for monoenergetic neutrons below 100MeV have a recoil proton plateau and an edge around the maximum light output which increases with increasing neutron energy, while on the other hand, for energies above 100 MeV, the plateau and the edge become unclear because the proton range starts to exceed the detector size allowing protons to escape. [Copyright &y& Elsevier]

Abstract: The avalanche photodiodes (APDs) have attracted considerable attention in various field of experimental physics, but their uses are still limited in only a few experiments, possibly due to their small surface areas. Here, we report the development of the large-area ( square) APDs, for future applications to high-resolution X-rays and -rays detection. We have made two prototypes of reverse-type APDs based on different concepts, one consists of a array of pixels (APD1) and the other is a monolithic pixel of size (APD2) to achieve a large effective area. By comparing the dark current and gain characteristics at room temperature and lightly cooled environment (), we quantitatively discussed the origin of predominant noise source at different temperatures. As a performance demonstration of newly developed APDs, we made a scintillation -ray detector consisting of a CsI(Tl) crystal and a 2cm-square APD. The best FWHM energy resolution of 5.5 were obtained for -rays at room temperature. Similarly, the best FWHM energy resolution of were obtained for 122keV -rays at lightly cooled environment. We showed that the minimum detectable energy for scintillation light was 15keV at and less than 5keV at . [Copyright &y& Elsevier]

Abstract: We describe the neutron polarimeter NPOL3 for the measurement of polarization transfer observables with a typical high resolution of 300keV at . The NPOL3 system consists of three planes of neutron detectors. The first two planes for neutron polarization analysis are made of 20 sets of one-dimensional position-sensitive plastic scintillation counters with a size of 100cm 10cm 5cm, and they cover the area of . The last plane for detecting doubly scattered neutrons or recoiled protons is made of the two-dimensional position-sensitive liquid scintillation counter with a size of . The effective analyzing powers and double scattering efficiencies were measured by using the three kinds of polarized neutrons from the , , and reactions at . The performance of NPOL3 defined as are similar to that of the Indiana Neutron POLarimeter by taking into account for the counter configuration difference between these two neutron polarimeters. [Copyright &y& Elsevier]

Abstract: We have carried out study of a large area , reverse-type avalanche photodiode (APD) recently developed by Hamamatsu photonics. It has low dark current of 3nA at room temperature, and the gain stability was almost the same as prototypical APDs reported in our previous paper. We studied the performance as a -ray detector with four scintillators, CsI(Tl), BGO, GSO(Ce), and YAP(Ce) crystals. For example we obtained the best energy resolution of (FWHM) for 662keV -rays, as measured with a CsI(Tl) crystal. The minimum detectable energy was as low as 10keV at and 3.1keV at . Thanks to its large effective area, this APD can effectively read out photons from larger size scintillators. When coupling to a BGO plate of 3mm thickness, an FWHM energy resolution of was obtained for 662keV -rays, with the minimum detectable energy of about 60keV at . These results suggest that our prototype APD can be a promising device for various applications replacing traditional PMTs such as use in space for Japan''s future X-ray astronomy mission NeXT. [Copyright &y& Elsevier]

A new method of emulsion chamber analysis by using an image scanner is developed in order to process a large number of X-ray films used in the Tibet hybrid experiment which is carried out to observe primary proton spectrum in the PeV region. The experimental procedure in this method consists of multiple steps of processing the image of the X-ray films, i.e. the detection of cascade showers induced by high-energy γ-rays, the noise reduction, the spatial reconstruction of γ-families and their energy determination. The quality of the results obtained by the new method is compared with that obtained by the current manual method or Monte Carlo simulations. It is shown that sufficiently high quality of the emulsion chamber analysis is realized by the automatic method both in energy and geometrical resolution. [Copyright &y& Elsevier]