Neutral Gas Pressure Gauge

[Objectives]
Partial pressure of D₂ and He gas under the baffle and around main plasma are measured.

[Diagnostic Method]
Intensity of Da and HeI from penning discharge region depend on partial pressure of D₂ and He gasses. Da and HeI emission are guided to the diagnostic hall with optical fiber and measured by photomultiplier tubes with bandpass filter.

[Specification]

Detector : Photomultiplier tubes with bandpass filters

・ Time resolution : ~4 ms (Sampling time)
{Pressure response are delayed about 0.1 sec from those in the vacuum vessel, because the guages are placed about 4 m away from vacuum vessel}

・ Position

around main plasma : P-9 section, U1-2&U2-2 port

under the baffle : P-10 U2-2 port

Detector	:	Photomultiplier tubes with bandpass filters
・ Time resolution	:	~4 ms (Sampling time) {Pressure response are delayed about 0.1 sec from those in the vacuum vessel, because the guages are placed about 4 m away from vacuum vessel}
・ Position
around main plasma	:	P-9 section, U1-2&U2-2 port
under the baffle	:	P-10 U2-2 port