MAX: a gamma-ray lens for nuclear astrophysics

Abstract

The mission concept MAX is a space borne crystal diffraction telescope, featuring a broad-band Laue lens optimized for the observation of compact sources in two wide energy bands of high astrophysical relevance. For the first time in this domain, gamma-rays will be focused from the large collecting area of a crystal diffraction lens onto a very small detector volume. As a consequence, the background noise is extremely low, making possible unprecedented sensitivities. The primary scientific objective of MAX is the study of type Ia supernovae by measuring intensities, shifts and shapes of their nuclear gamma-ray lines. When finally understood and calibrated, these profoundly radioactive events will be crucial in measuring the size, shape, and age of the Universe. Observing the radioactivities from a substantial sample of supernovae and novae will significantly improve our understanding of explosive nucleosynthesis. Moreover, the sensitive gamma-ray line spectroscopy performed with MAX is expected to clarify the nature of galactic microquasars (e + e -annihilation radiation from the jets), neutrons stars and pulsars, X-ray Binaries, AGN, solar flares and, last but not least, gamma-ray afterglow from gamma-burst counterparts.

HAXTEL: A Laue lens telescope development project for a deep exploration of the hard X-ray sky (> 60 keV)

“…This development is complementary to that which is being performed by other authors (e.g., von Ballmoos et al 2004), devoted to the development of Laue lenses for the study of nuclear gamma-ray lines.…”

“…Also for a deep study of the high energy nuclear lines (>600 keV), Laue lenses appear to be the best solution, but they require a specific design to maximize the sensitivity in a band around the expected energy of the lines (see, e.g., [2]). …”

The gamma ray lens – an ESA technology reference study

“…MAX is a gamma ray focusing mission based on Laue crystals, proposed by CESR (Centre d'Etude Spatiale des Rayonnements), Toulouse [3]. The mission is sized to fit both detector and lens spacecraft into a single Soyuz Fregat launcher.…”

High diffraction efficiency, broadband, diffraction crystals for use in crystal diffraction lenses

“…The lens was tested with 8 different energies from 276.32 to 661.65 keV from 3 different radioactive isotopes. The lens demonstrated the feasibility of the concept and led to a collaboration between Argonne and CESR, Toulouse [5][6][7][8] This led to the demonstration of a lens for astrophysics in the CLAIRE program [8]. The Laue lenses built in these collaborations all used mosaic crystals, where one had to trade diffraction efficiency against energy bandwidth and visa versa.…”

“…The Laue lenses built in these collaborations all used mosaic crystals, where one had to trade diffraction efficiency against energy bandwidth and visa versa. The success of Claire program has led to the proposal of the MAX space mission [7] As discussed by von Ballmoos et al [7] the requirement to observe a reasonable number of supernovae per year places important requirements on the sensitivity. A factor of four improvement in diffraction efficiency allows one to see supernova in 8 times as many galaxies.…”