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-ray detectionKimura, Atsushi; Furutaka, Kazuyoshi; Goko, Shinji; Harada, Hideo; Igashira, Masayuki*; Kamiyama, Takashi*; Katabuchi, Tatsuya*; Kin, Tadahiro; Kino, Koichi*; Kitatani, Fumito; et al.
Proceedings of 2009 IEEE Nuclear Science Symposium and Medical Imaging Conference (2009 NSS/MIC) (CD-ROM), p.138 - 143, 2009/10
To correct dead-time effect and measure high-precision neutron cross-section data, we have tested a dead-time correction method. In this method, random timing pulses are input to every pre-amplifiers of the Ge crystals via test-signal inputs. Both the random timing pulses and the other pulses originated from prompt -rays are measured with our DAQ. At the same time, the inputs random pulses are counted with another system consisting of a fast timing amplifier, a CFD, and a counter. Because dead-time affects similarly both the random timing pulses and the measured prompt -rays, we can calculate dead-time by comparing the number of the input random pulses measured using the counter with the area of the peak due to the pulses from the pulse generator measured with our DAQ.
Kawachi, Naoki; Suzui, Nobuo; Ishii, Satomi; Ito, Sayuri; Ishioka, Noriko; Kikuchi, Kaori*; Tsukamoto, Takashi*; Kusakawa, Tomoyuki*; Fujimaki, Shu
Proceedings of 2009 IEEE Nuclear Science Symposium and Medical Imaging Conference (2009 NSS/MIC) (CD-ROM), p.1257 - 1258, 2009/10
germanium spectrometer for nuclear data measurements at J-PARCKin, Tadahiro; Furutaka, Kazuyoshi; Goko, Shinji; Harada, Hideo; Igashira, Masayuki*; Kamiyama, Takashi*; Katabuchi, Tatsuya*; Kimura, Atsushi; Kino, Koichi*; Kitatani, Fumito; et al.
Proceedings of 2009 IEEE Nuclear Science Symposium and Medical Imaging Conference (2009 NSS/MIC) (CD-ROM), p.1194 - 1197, 2009/10
For development of advanced reactors such as fast breeder reactors or accelerator driven systems, nuclear data of minor actinides (MAs) and long-lived fission products (LLFPs) are important for calculation of burning rates of fuels and transmutation rates to reduce the radio-toxicity of wastes. However, these data are insufficient at present in quantity and quality. To overcome/improve such a situation, we developed a 4 germanium spectrometer to measure neutron capture cross sections of MAs and LLFPs by time-of-flight measurements using pulsed neutron beams. At the conference, we will report details of the arrangement and characteristics of the spectrometer, such as detection efficiency, energy resolution and signal-to-background ratio, using results of measurement of standard sources. We will also show example of TOF spectra to report time resolution.
Furutaka, Kazuyoshi; Kimura, Atsushi; Koizumi, Mitsuo; Toh, Yosuke; Kin, Tadahiro; Nakamura, Shoji; Oshima, Masumi
Proceedings of 2009 IEEE Nuclear Science Symposium and Medical Imaging Conference (2009 NSS/MIC) (CD-ROM), p.2229 - 2233, 2009/10
To measure and improve differential linearity of flash ADCs used in integrated VME ADC modules, exponentially falling pulse-tails were digitized and counts of the resultant digital codes were recorded. The obtained histograms were fit to a function to deduce smoothly varying curves which should correspond to that obtained in the case of ideal linearity, and were compared to the fit value to calculate code width for each code. The obtained results show zigzag shaped deviation of about 10 % in magnitude from unity in the whole range and some large spikes which are as large as 100 %. A simple method is proposed to correct the nonlinearity using the ratios in post-processors following the ADCs. In the conference, the results of the correction will be presented.