Calibration of the OHREX high-resolution imaging crystal spectrometer at the Livermore electron beam ion traps

Journal Article · Tue Nov 15 00:00:00 EST 2016 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4959947· OSTI ID:22596529

Hell, N. ^[1]; Beiersdorfer, P.; Magee, E. W.; Brown, G. V. ^[1]

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1. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

We report the calibration of the Orion High-Resolution X-ray (OHREX) imaging crystal spectrometer at the EBIT-I electron beam ion trap at Livermore. Two such instruments, dubbed OHREX-1 and OHREX-2, are fielded for plasma diagnostics at the Orion laser facility in the United Kingdom. The OHREX spectrometer can simultaneously house two spherically bent crystals with a radius of curvature of r = 67.2 cm. The focusing properties of the spectrometer allow both for larger distance to the source due to the increase in collected light and for observation of extended sources. OHREX is designed to cover a 2.5°–3° spectral range at Bragg angles around 51.3°. The typically high resolving powers at these large Bragg angles are ideally suited for line shape diagnostics. For instance, the nominal resolving power of the instrument (>10 000) is much higher than the effective resolving power associated with the Doppler broadening due to the temperature of the trapped ions in EBIT-I. The effective resolving power is only around 3000 at typical EBIT-I conditions, which nevertheless is sufficient to set up and test the instrument’s spectral characteristics. We have calibrated the spectral range for a number of crystals using well known reference lines in the first and second order and derived the ion temperatures from these lines. We have also made use of the 50 μm size of the EBIT-I source width to characterize the spatial focusing of the spectrometer.

• OSTI ID: 22596529
• Journal Information: Review of Scientific Instruments, Vol. 87, Issue 11; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BRAGG REFLECTION
CALIBRATION
CRYSTALS
DOPPLER BROADENING
ELECTRON BEAMS
ELECTRONS
FOCUSING
IMAGES
ION TEMPERATURE
IONS
LASERS
PLASMA DIAGNOSTICS
RESOLUTION
SHAPE
SPECTROMETERS
SPHERICAL CONFIGURATION
TRAPPING
TRAPS
WIDTH
X RADIATION