Improved charge coupled device detectors for the edge charge exchange spectroscopy system on the DIII-D tokamak

Journal Article · Mon Jan 01 04:00:00 EST 2001 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.1319363· OSTI ID:40204773

Burrell, K H; Kaplan, D H; Gohil, P; Nilson, D G; Groebner, R J; Thomas, D M

Charge exchange spectroscopy is one of the key ion diagnostics on the DIII-D tokamak. It allows measurement of impurity densities, toroidal and poloidal rotation speeds, ion temperatures, and the radial electric field. For the 2000 experimental campaign, we have replaced the intensified photodiode array detectors on the edge portion of the system with advanced charge-coupled device (CCD) detectors mounted on faster (f/4.7) Czerny--Turner spectrometers equipped with toroidal mirrors. The combination has improved the photoelectron signal level by about a factor of 20 and the signal to noise by a factor of 2--8, depending on the absolute signal level and readout mode. A major portion of the signal level improvement comes from the improved quantum efficiency of the back-illuminated, thinned CCD detector (70% to 85% quantum efficiency for the CCD versus 10% for the image intensifier) with the remainder coming from the faster spectrometer. The CCD camera also allows shorter minimum integration times: 0.33 ms while archiving to computer memory and 0.15 ms using temporary storage on the CCD chip.

• Sponsoring Organization: (US)
• OSTI ID: 40204773
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 1 Vol. 72; ISSN 0034-6748
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CHARGE EXCHANGE
CHARGE-COUPLED DEVICES
DOUBLET-3 DEVICE
ELECTRIC FIELDS
IMAGE INTENSIFIERS
ION TEMPERATURE
QUANTUM EFFICIENCY
SPECTROSCOPY