Laue diffraction lenses for astrophysics: From theory to experiments

Halloin, Hubert

doi:10.1007/s10686-006-9063-0

Cited by 16 publications

(9 citation statements)

References 14 publications

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“…Finally, the complementary characteristics of a Laue lens and of a Compton detector with respect to photon polarisation render their combination a powerful polarimeter. At nuclear line energies a Laue lens does not change the polarisation of the diffracted photons (Halloin and Bastie, 2006;Halloin 2006), while a Compton detector is intrinsically ideally suited for performing polarimetry because of the azimuthal variation of the scattering direction for linearly polarized photons (Lei et al, 1997). The combination of a Laue lens with a Compton detector will thus open a new observational window on many gamma-ray sources in which strong magnetic fields are present, such as pulsars, or on jets expelled by compact, accreting objects.…”

Section: Discussionmentioning

confidence: 99%

Monte Carlo study of detector concepts for the MAX Laue lens gamma-ray telescope

et al. 2006

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MAX is a proposed Laue lens gamma-ray telescope taking advantage of Bragg diffraction in crystals to concentrate incident photons onto a distant detector. The Laue lens and the detector are carried by two separate satellites flying in formation. Significant effort is being devoted to studying different types of crystals that may be suitable for focusing gamma rays in two 100 keV wide energy bands centered on two lines which constitute the prime astrophysical interest of the MAX mission: the 511 keV positron annihilation line, and the broadened 847 keV line from the decay of 56 Co copiously produced in Type Ia supernovae. However, to optimize the performance of MAX, it is also necessary to optimize the detector used to collect the source photons concentrated by the lens. We address this need by applying proven Monte Carlo and event reconstruction packages to predict the performance of MAX for three different Ge detector concepts: a standard coaxial detector, a stack of segmented detectors, and a Compton camera consisting of a stack of strip detectors. Each of these exhibits distinct advantages and disadvantages regarding fundamental instrumental characteristics such as detection efficiency or background rejection, which ultimately determine achievable sensitivities. We conclude that the Compton camera is the most promising detector for MAX in particular, and for Laue lens gamma-ray telecopes in general.

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Section: Discussionmentioning

confidence: 99%

Monte Carlo study of detector concepts for the MAX Laue lens gamma-ray telescope

et al. 2006

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“…1. [12][13][14]33 The focal length F is given by F = r/ tan (2θ), where r is the radius of a given ring of crystals, and θ is the Bragg angle of the crystals. 13,34 The wavelength bandpass of a single crystal resembles a delta function centered on the wavelength where the Bragg condition is met.…”

Section: Laue Lensesmentioning

confidence: 99%

“…The CLAIRE mission used a 45 cm diameter, 2.77 m focal length Laue lens made of 556 Ge-Si crystals to achieve a 170 keV angular resolution of 18 arcmin. 33 Small amounts of Si were added to the Ge during the crystal growth process to make mosaic crystals with a bandpass of 3 keV centered on 170 keV. The experiment was flown on a stratospheric balloon flight in 2001 and successfully detected γ-rays from the Crab Pulsar and Nebula.…”

Section: Laue Lensesmentioning

confidence: 99%

The 511-CAM Mission: A Pointed 511 keV Gamma-Ray Telescope with a Focal Plane Detector Made of Stacked Transition Edge Sensor Microcalorimeter Arrays

Shirazi¹,

Hossen²,

Becker³

et al. 2022

Preprint

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The 511 keV γ-ray emission from the galactic center region may fully or partially originate from the annihilation of positrons from dark matter particles with electrons from the interstellar medium. Alternatively, the positrons could be created by astrophysical sources, involving exclusively standard model physics. We describe here a new concept for a 511 keV mission called 511-CAM (511 keV gamma-ray CAmera using Micro-calorimeters) that combines focusing γ-ray optics with a stack of Transition Edge Sensor (TES) microcalorimeter arrays in the focal plane. The 511-CAM detector assembly has a projected 511 keV energy resolution of 390 eV Full Width Half Maximum (FWHM) or better, and improves by a factor of at least 11 on the performance of state-of-the-art Ge-based Compton telescopes. Combining this unprecedented energy resolution with sub-arcmin angular resolutions afforded by Laue lens or channeling optics could make substantial contributions to identifying the origin of the 511 keV emission by discovering and characterizing point sources and measuring line-of-sight velocities of the emitting plasmas.

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“…Conversely, the tails of the PSF are basically determined by the tangential size of the crystals. The PSF can also be calculated if the lens is composed of mosaic crystals (Halloin, 2005). In this case, the width of the image spot is at least equal to the radial size of the crystals L r and becomes larger, owing to the so-called mosaic defocusing, as L S increases over the value 2 lnð2Þ ½ 1=2 L r =m, m being the mosaicity of the crystals (Halloin & Bastie, 2005).…”

Section: Point Spread Function Calculationmentioning

confidence: 99%

Design study of a Laue lens for nuclear medicine

et al. 2015

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A Laue lens is an ensemble of crystals capable of focusing, through diffraction in transmission geometry, a fraction of the photons emitted by an X- or gamma-ray source onto a small area of a detector. The present study allows obtaining a thorough understanding about the effect of each system parameter on the efficiency, the resolution, and the field of view of the lens. In this way, the structure and the size of the crystals can be set to achieve a compact lens capable of providing a high-resolution image of the radioactivity distribution lying inside a restricted region of the patient's body. As an application, a Laue lens optimized at 140.5 keV, the gamma-line emitted by 99mTc, has been designed. The lens is composed by 10 rings of Ge crystals with curved diffracting planes and focuses the photons onto a detector 50 cm apart from the source with 1.16x10^-5 efficiency and 0.2 mm resolution. The combination of these two important figures of merit makes the proposed device to be better performing than a pinhole SPECT (Single Photon Emission Computed Tomography), which is the technique employed for top-resolution images in nuclear medicine. Finally, the imaging capability of the designed lens has been tested through simulations performed with a custom-made Monte Carlo code

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Laue diffraction lenses for astrophysics: From theory to experiments

Cited by 16 publications

References 14 publications

Monte Carlo study of detector concepts for the MAX Laue lens gamma-ray telescope

Monte Carlo study of detector concepts for the MAX Laue lens gamma-ray telescope

The 511-CAM Mission: A Pointed 511 keV Gamma-Ray Telescope with a Focal Plane Detector Made of Stacked Transition Edge Sensor Microcalorimeter Arrays

Design study of a Laue lens for nuclear medicine

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