ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
In a previous work [Zurro et al., Rev. Sci. Instrum. 68, 680 (1997)], we outlined designs for several detector systems, based on rare-earth phosphor powders, with application as broadband VUV plasma radiation monitors in the TJ-II flexible heliac device. In addition to their immunity to microwave power, to ground loops, and to any kind of EMI, the phosphor powders considered as suitable candidates can withstand the high temperatures of the TJ-II vacuum chamber (150 °C), while possessing good sensitivity across the x-ray to UV range and fast response times. Among those selected was Y3Al5O15:Ce (P-46), which emits at 530 nm and when examined, it was found to be particularly suitable for our application due to its very fast response time (∼0.1 μs). We report on absolute efficiency measurements performed between 40 and 200 nm using a calibrated VUV source, and made on thin P-46 phosphor screens, having thicknesses between 1 and 20 mg/cm2. We combine these results with measurements made at visible wavelengths and in the x ray [A. Baciero et al., in Diagnostics for Experimental Thermonuclear Fusion Reactors 2, edited by P. E. Stott et al. (Plenum, New York, 1998)] to obtain fitting parameters for models used to predict phosphor response efficiencies in transmission and reflection modes. These models can be used to tailor the phosphor screen thickness to the radiation range of interest while reducing background noise. Such screens are currently used on the TJ-II. © 1999 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1149527
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