Gamma-ray pluse height analysis


[Objectives]
To measure gamma-ray spectrum originated from nuclear reactions between fast ions and impurity ions.

[Detectors, Diagnostic Method]
Time resolved gamma-ray spectra in an energy range of 0.5 to 20 MeV are measured by a NaI(Tl) scintillator surround by 50 cm thick polyethylene and 30 cm thick lead shield.

Following gamma-rays originated from inelastic collisions have been measured in JT-60U ICRF experiments to identify energy distribution of MeV-energy protons.

(1) p + 20Ne--> p + 20Ne + gamma(1.6MeV)
(2) p + 11B--> p + 11B + gamma(2.1MeV)
(3) p + 12C--> p + 12C + gamma(4.4MeV)

[Specifications]
¥Time resolusion : 50 ms (spectra), 1 ms (count)
¥Spatial resolution: about 30 cm at plasma center (depends on collimator)
¥Energy range: 0.5 - 20 MeV (256 channel)
¥Position: P-18 section, U2-2a port
¥Detector: NaI(Tl) ,12.7 cm in diameter and 12.7 cm in length

[Reference]
(1) T.Kondoh et al., "Gamma-ray measurements in JT-60U ICRF heated plasma", Journal of Plasma and Fusion Research, Vol 72, No.12 1397(1996).