Testing of a gamma ray imaging system at Omega

Lemieux, Daniel; Barber, H. Bradford; Grim, G.; Clark, D.D.; Danly, C. R.; Aragonez, Robert J.; Griego, J.R.; Fatherley, V. E.; Fastje, Daivd

doi:10.1117/12.2024400

Cited by 4 publications

(7 citation statements)

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“…For LYSO:Ce, 20 mm is sufficient for 40% of the 4.44 MeV gamma rays to interact. At 4.44 MeV, a GEANT4 simulation [2] showed a lateral spread of energy deposition of 1.1 mm FWHM for BGO and 1.09 mm FWHM for LYSO:Ce, which is consistent with the choice of a 1 mm pixel size [1]. …”

Section: Scintillator Propertiesmentioning

confidence: 74%

“…It was developed as part of a program to demonstrate the possibility of gamma-ray imaging as a diagnostic tool to monitor target compression in inertial confinement fusion at the National Ignition Facility (NIF). The Prototype Imager has been described elsewhere [1], as has its initial testing at the OMEGA Laser Facility at the University of Rochester [1]. Figure 2 shows a 200 µm-pinhole image of a compressed 3 He target pellet taken at the OMEGA Laser; the bright central spot corresponds to thermal x-rays at a few tens of keV, while the surrounding extended emission is from hard x-rays (a few hundred keV) produced by Bremsstrahlung from energetic electrons due to the laser interaction with the plastic shell of the pellet.…”

Section: Introductionmentioning

confidence: 99%

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Imaging properties of pixellated scintillators with deep pixels

et al. 2014

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We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10×10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm × 1mm × 20 mm pixels) made by Proteus, Inc. with similar 10×10 arrays of LSO:Ce and BGO (1mm × 1mm × 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10×10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of 176Lu in LSO:Ce and LYSO:Ce detectors.

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Section: Scintillator Propertiesmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Imaging properties of pixellated scintillators with deep pixels

et al. 2014

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“…[5] These experiments used a 3 He filled capsule whose plastic shell released hot electrons that produced bremsstrahlung radiation when shot with 27 KJ of laser energy from 60 lasers. This produced abundant soft X-rays from the core and hard x-rays from the plastic shell as it moved inward.…”

Section: High Intensity Gamma Source (Higs) Experimentsmentioning

confidence: 99%

Testing of a gamma ray imaging system at the High Intensity Gamma Source

et al. 2014

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Testing of the gamma ray imaging system will continue at the High Intensity Gamma Source (HIGS) at Duke University. Previous testing at OMEGA gave useful information but at much lower photon energies. Utilizing HIGS 10 8 gammas/s and its tight beam we will be able to characterize the system in the energy regime that it was designed for namely 4.44 MeV. HIGS offers the ability to tune the beam's energy from 1--20 MeV by way of controlling the inverse Compton scattering off of a relativistic electron beam. With this feature characterization in a range of energies will be possible. Targets were made using a ray--tracing program that replicates a 12--micron ideal pinhole and a 20 cm long 300--micron gold penumbra aperture. The latter will require reconstruction of the coded images.

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“…Work on imaging systems of this type is just beginning, but this approach is described in a paper by Lemieux, et al [7]; such gamma-ray imaging systems use pixellated scintillator arrays read out by an image intensifier and a CCD camera. Tests of a prototype system are described in a report in this conference [8]. The prototype gamma-ray imaging system is shown in Figure 4, and results for gamma-ray interactions in a scintillator block from a radioactive source are shown in Figure 5.…”

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confidence: 98%

“…Prototype imager comprising an image intensifier and an array of pixellated Scintillators[8]. The scintillator array contains 3700 pixels of LYSO:Ce scintillator (1 mm pitch and 20 mm long) in 10 x 10 blocks.…”

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confidence: 99%

Preliminary investigation fo the non-linear response of image intensifiers used for gamma-ray imaging

et al. 2013

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Image intensifiers combined with columnar scintillators have found application in x-ray and gamma-ray, biomedical imaging and other fields. In scintillator imaging, hundreds or thousands of optical photons can illuminate the faceplate of the image intensifier in a small area, essentially simultaneously. This is a situation not found in the typical design application for an image intensifier, night vision or low-light-level imaging. Microchannel plates (MCPs) are known to exhibit gain saturation that could result in non-linear signal response in scintillator imaging, limiting quantitative measurement capabilities. A calibrated LED photon source was developed that can provide a known average number of photons per unit area in a small spot size, similar to that seen due to a gamma-ray interaction in a BazookaSPECT imager. A BazookaSPECT imager is composed of a columnar scintillator and an image intensifier, with output light optically imaged onto a CCD camera. The calibrated source was used to investigate gain-saturation effects for two Proxivision, GmbH image intensifiers, a single-stage BV 2583 EZ and a two stage BV 2583 QZ-V 100N in a BazookaSPECT imaging configuration. No gain saturation was found for the single-stage image intensifier up to more than 100 optical photons per microchannel, but significant gain-saturation non-linearities were measured in the two-stage image intensifier at high gains for >12 optical photons per microchannel. Implications for scintillator imaging using such systems are discussed.

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Testing of a gamma ray imaging system at Omega

Cited by 4 publications

References 0 publications

Imaging properties of pixellated scintillators with deep pixels

Imaging properties of pixellated scintillators with deep pixels

Testing of a gamma ray imaging system at the High Intensity Gamma Source

Preliminary investigation fo the non-linear response of image intensifiers used for gamma-ray imaging

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