D-alpha/H-alpha emission measurement

Poloidal profiles of D/H emission (656.3nm) originated from neutral deuterium/hydrogen in the edge plasma are measured. Studies of particle recycling and neutral transport in main edge and divertor have been accomplished. Fast sampling data have been used for ELM, pedestal plasma and plasma detachment studies.

Two different data acquisition systems (SLOW & FAST) shear the same PMT for all (25) channels.

Detector : 25 sets of Photomultiplier tubes with bandpass filter (636.28nm FWHM : 0.8 nm)

Time resolution, Sampling period, Signal resolution:

Operation: Data sampling and control systems were revised for long-pulse operation of JT-60U from 2003, SLOW sampling system(A5B) was replaced to new transient recorders&network-controller, and Acquisition speed of FAST sampling system was enhanced from 2005.

Slow Sampling (25ch) : 0.25ms/15s, 0.25ms/30s, 0.5ms/60s, 16bit resolution, Max. 128kword/ch
(Low-pass-filters of fc=5kHz).

Fast Sampling (18ch) : 5-200 micro-s/1.2s - 51s, 12bit signal resolution, Max. 512kword/ch
(Low-pass-filters of fc=10-500kHz is programmable)
(Amp gain of x0.5, x1, x2, x5 is programmable)
Maximum 5 "Burst period" (faster sampling mode) was available.
Position : P-5 section (25 poloidal array)

Spatial resolution : 5~10cm (poloidal array)

* Major Development/Modification History is listed Here.