A low-cost multichannel Thomson scattering system for CDX-U
- Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
A multichannel Thomson scattering system has been developed for the CDX-U spherical torus. The system is designed for 10thinspeV{lt}T{sub e}{lt}400thinspeV, n{sub e}{gt}10{sup 18}thinspm{sup {minus}3}, which includes typical and predicted central and edge conditions in CDX-U. The system uses two laser passes to double the scattered photons from a 5 J ruby laser. The beam path is vertical through the {approximately}66 cm (elongated) diameter of the plasma and is movable in the major-radial direction, enabling coverage of nearly 70{percent} of the major-radial plasma extent. Twelve channels over the vertical minor radius provide {approximately}2.5 cm spatial resolution. The main collecting lens, located 45 cm from the laser beamline, provides high solid angle ({Delta}{Omega}{approximately}0.01) light collection using a 15 cm diam lens. The system makes maximum usage of an optically fast (f/1.8) compact imaging spectrometer. An intensified charge coupled device with a GaAs photocathode provides quantum efficiency of {approximately}20{percent} at 6943 {Angstrom}. The combination of plasma access, multiple beam passes, high-throughput spectrometer, and high quantum efficiency detector provide for very high total photon statistics in a relatively simple and inexpensive system.
- OSTI ID:
- 295650
- Report Number(s):
- CONF-980605-; ISSN 0034-6748; TRN: 99:001836
- Journal Information:
- Review of Scientific Instruments, Vol. 70, Issue 1; Conference: 12. topical conference on high-temperature plasma diagnostics, Princeton, NJ (United States), 7-11 Jun 1998; Other Information: PBD: Jan 1999
- Country of Publication:
- United States
- Language:
- English
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