Fast collimated neutron flux measurement using stilbene scintillator and flashy analog-to-digital converter in JT-60U

Journal Article · Sun Oct 15 00:00:00 EDT 2006 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.2221927· OSTI ID:20861242

Ishikawa, M; Itoga, T; Okuji, T; Nakhostin, M; Shinohara, K; Hayashi, T; Sukegawa, A; Baba, M; Nishitani, T ^[1]

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1. Cyclotron and Radioisotope Center, Tohoku University, Aoba 6-3, Sendai, Miyagi 980-8578 (Japan)

A line-integrated neutron emission profile is routinely measured using the radial neutron collimator system in JT-60U tokamak. Stilbene neuron detectors (SNDs), which combine a stilbene organic crystal scintillation detector (SD) with an analog neutron-gamma pulse shape discrimination (PSD) circuit, have been used to measure collimated neutron flux. Although the SND has many advantages as a neutron detector, the maximum count rate is limited up to {approx}1x10{sup 5} counts/s due to the analog PSD circuit. To overcome this issue, a digital signal processing system (DSPS) using a flash analog-to-digital converter (Acqiris DC252, 8 GHz, 10 bits) has been developed at Cyclotron and Radioisotope Center in Tohoku University. In this system anode signals from photomultiplier of the SD are directory stored and digitized. Then, the PSD between neutrons and gamma rays is performed using software. The DSPS has been installed in the vertical neutron collimator system in JT-60U and applied to deuterium experiments. It is confirmed that the PSD is sufficiently performed and collimated neutron flux is successfully measured with count rate up to {approx}5x10{sup 5} counts/s without the effect of pileup of detected pulses. The performance of the DSPS as a neutron detector, which supersedes the SND, is demonstrated.

• OSTI ID: 20861242
• Journal Information: Review of Scientific Instruments, Vol. 77, Issue 10; Other Information: DOI: 10.1063/1.2221927; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANALOG-TO-DIGITAL CONVERTERS
COLLIMATORS
COUNTING CIRCUITS
COUNTING RATES
CYCLOTRONS
GAMMA RADIATION
GHZ RANGE 01-100
JT-60U TOKAMAK
NEUTRON DETECTION
NEUTRON DETECTORS
NEUTRON EMISSION
NEUTRON FLUX
NEUTRONS
PULSE SHAPERS
PULSES
SIGNALS
SOLID SCINTILLATION DETECTORS
STILBENE