Lynx x-ray microcalorimeter

Abstract

Lynx is an x-ray telescope, one of four large satellite mission concepts currently being studied by NASA to be a flagship mission. One of Lynx's three instruments is an imaging spectrometer called the Lynx x-ray microcalorimeter (LXM), an x-ray microcalorimeter behind an x-ray optic with an angular resolution of 0.5 arc sec and ∼2 m 2 of area at 1 keV. The LXM will provide unparalleled diagnostics of distant extended structures and, in particular, will allow the detailed study of the role of cosmic feedback in the evolution of the Universe. We discuss the baseline design of LXM and some parallel approaches for some of the key technologies. The baseline sensor technology uses transition-edge sensors, but we also consider an alternative approach using metallic magnetic calorimeters. We discuss the requirements for the instrument, the pixel layout, and the baseline readout design, which uses microwave superconducting quantum interference devices and high-electron mobility transistor amplifiers and the cryogenic cooling requirements and strategy for meeting these requirements. For each of these technologies, we discuss the current technology readiness level and our strategy for advancing them to be ready for flight. We also describe the current system design, including the block diagram, and our estimate for the mass, power, and data rate of the instrument.

Demonstration of Fine-Pitch High-Resolution X-ray Transition-Edge Sensor Microcalorimeters Optimized for Energies below 1 keV

“…An X-ray source within the desired range of X-ray energies for this device, with known intrinsic linewidth and sufficient flux, was not available. Using a commercial X-ray source 1 with an Al target, we measured the detector response to 1.5 keV X-rays, which is factor of two higher than the maximum X-ray energy targeted. The heat capacity of the pixel is optimized for X-rays less than 0.75 keV, and therefore the performance is expected to deteriorate at these energies due to the nonlinearity of the detector response.…”

“…We are developing arrays of fine-pitch X-ray TES microcalorimeters for use in future space-based X-ray astrophysics missions such as the proposed Lynx X-ray Microcalorimeter. The Lynx mission is one of four flagship mission concepts currently being studied for consideration in the 2020 Astrophysics Decadal Survey [1]. The Lynx X-ray Microcalorimeter (LXM), one of three instruments the spacecraft carries, is a microcalorimeter detector consisting of one main array and two subarrays [2].…”

Extension of the Energy Range Accessible with a TES Using Bath Temperature Variations

“…We can observe that α and β, and so the transition shapes, are different at different bath temperatures, unlike the model described in [5] which assumed constant transition shape. This will hence ultimately affect the energy resolution and the slew rate.…”

“…Secondly, the TES gain will be more sensitive to thermal fluctuations in T b , and thirdly, the lower current responsivity of the device may increase the impact of any white noise in the readout chain. A preliminary simulation was done in Bandler et al [5] in order to evaluate how the estimated energy resolution and energy range might change as a function of the bath temperature (Fig. 1).…”

The high energy Universe at ultra-high resolution: the power and promise of X-ray interferometry

“…TESs operate at a temperature of 100 mK, and thus require a cryogenic infrastructure. The most ambitious TES instrument proposed so far, for the proposed Lynx X-ray observatory, consists of O(10 5 ) 50 μm pixels, adding up to only 2.1 cm 2 [3]. This thus invites a breakthrough technology in either X-ray detector read-out, focused optics for XRI, or massive parallelization of cryogenic systems.…”