Hard x-ray pluse height analysis

[Objectives]
Radial profile and energy distribution of fast electrons produced by lower hybrid waves are measured.

[Detectors, Diagnostic Method]
Seven channel sodium-iodide (NaI(Tl)) scintillator-photomultiplier combination is employed to measure the x-ray spectra from 80 keV to 1000 keV.

Detectors are shielded by 23 cm of lead and 50 cm polyethylene to reduce the back-ground gamma-rays.

[Specifications]

-Time resolusion	: 50/200 ms (spectra), 1/4 ms (count) [for 12.8/51.2 s]
-Energy range	: 80 - 1000 keV
-Position	: P-1 section, IN-2A-c port (poloidal array :7 channel)
	: P-7 section, R-9-c port (counter-tangential :1 channel)
	: P-8 section, R-6-e port (co -tangential :1 channel)
-Detector	: NaI(Tl) 5.08 cm in diameter, 5.08 cm in length

[Reference]
(1) T.Kondoh et al., "Absorption profile estimation of Lower Hybrid
Waves from the hard x-ray and soft x-ray response", Review of JT-60U experimental results from March to October, 1991, JAERI-M 92-073, 300(1991).
(2) S.Ide et al., "Enhencement of absorption of lower hybrid wave by filling the spectral gap", Physical Review Letters, Vol.73 2312 (1994).