Image plates as x-ray detectors in plasma physics experiments

Abstract

The performance of image plates based on the photostimulable phosphor BaF(Br,l):Eu2+ has been investigated and compared with x-ray film. Evaluation of detective quantum efficiency (DQE), sensitivity, dynamic range, and linearity was carried out for several types of commercially available image plate, using the Excalibur soft x-ray calibration facility at AWE. Image plate response was found to be linear over a dynamic range of 5 orders of magnitude. One type of image plate was found to have a number of advantages for soft x-ray detection, with a measured sensitivity 1 order of magnitude greater than that of Kodak Industrex CX and DEF-5 x-ray film. The DQE of this plate was found to be superior to that of film at low [less than 103 photons/(50 μm)2] and high fluxes [greater than 104 photons/(50 μm)2]. The spatial resolution of image plates, scanned with several models of commercial image plate readers, has been evaluated using a USAF resolution test target. The highest spatial resolution measured is 35 μm. Though this is significantly lower than the resolution possible with film, it is sufficient for many applications. Image plates were fielded in a refractive x-ray lens imaging diagnostic on the 1 TW Helen laser and these results are discussed.

High-space resolution imaging plate analysis of extreme ultraviolet (EUV) light from tin laser-produced plasmas

“…Other researchers have shown that the limits of space resolution for BAS-TR IPs to be below 100 µm. 12,32 Therefore, our results are well within reason and still represent a significant gain in data accuracy when considering angular distribution of EUV from Sn LPPs. Increased accuracy of angular distribution data presented here raises accuracy questions about angular distribution data from other techniques reported from so few data points.…”

“…10,11 Imaging plates (IPs) is a technique that has been successfully used to study x-rays in very high-energy plasma physics experiments. [12][13][14] An IP consists of a photostimulable material mounted on a flexible polymer film that contains europium ions that can be excited when exposed to photons and high-energy species. When exposed, the europium ions (Eu 2+ to Eu 3+ ) in the film are trapped in higher energy state lattice defects called F centers.…”

Wide angle crystal spectrometer for angularly and spectrally resolved x-ray scattering experiments

“…This translates into an expected peak flux of ϳ30 photons/ 50 m 2 for the resonance line. This is easily enough to create a detectable signal 12,15 and the linearity has been checked for this regime. The detective quantum efficiency for this type of image plate has not been measured at 4.75 keV but it has been measured to be 3 − 10% at low fluence for ϳ1.5 and 5.9 keV photons.…”

“…The instrument consists of a highly oriented pyrolytic graphite ͑HOPG͒ crystal 10,11 with a width of 100 mm in the sagittal ͑nonspec-tral͒ direction and mosaic spread of nominally 3.5°± 1.5°͑ ZYH grade͒. The crystal is placed symmetrically between the source and an image plate, 12,13 which is a required condition in order to achieve mosaic focusing. In experiments conducted at the Vulcan laser facility at the Rutherford Appleton Laboratory ͑UK͒, we were able to show that with this instrument we can collect simultaneously the angular variation in scatter, as well as spectral information, to distinguish between elastic scatter from the inelastic components that relate to bound-free Compton scatter features and free electron scatter features.…”

High harmonics from relativistically oscillating plasma surfaces—a high brightness attosecond source at keV photon energies

“…The x-ray signal (keV range) was observed using a broadband crystal spectrometer consisting of mica crystal in a von Hamos geometry [33] and a Fujifilm 'image plate' detector (BAS with 9 µm CH protective layer) [34]. The point spread function of the spectrometer was experimentally determined and the resolution (λ/ λ) of the spectrometer was determined to be ∼200 (limited by the crystal bending inaccuracies).…”