PolarLight: a CubeSat X-ray Polarimeter based on the Gas Pixel Detector

Abstract

The gas pixel detector (GPD) is designed and developed for high-sensitivity astronomical X-ray polarimetry, which is a new window about to open in a few years. Due to the small mass, low power, and compact geometry of the GPD, we propose a CubeSat mission Polarimeter Light (PolarLight) to demonstrate and test the technology directly in space. There is no optics but a collimator to constrain the field of view to 2.3 degrees. Filled with pure dimethyl ether (DME) at 0.8 atm and sealed by a beryllium window of 100 micron thick, with a sensitive area of about 1.4 mm by 1.4 mm, PolarLight allows us to observe the brightest X-ray sources on the sky, with a count rate of, e.g., ~0.2 counts/s from the Crab nebula. The PolarLight is 1U in size and mounted in a 6U CubeSat, which was launched into a low Earth Sun-synchronous orbit on October 29, 2018, and is currently under test. More launches with improved designs are planned in 2019. These tests will help increase the technology readiness for future missions such as the enhanced X-ray Timing and Polarimetry (eXTP), better understand the orbital background, and may help constrain the physics with observations of the brightest objects.

Accepted for publication in Experimental Astronomy

References in corpus (3)

• A Sealed Gas Pixel Detector for X-ray Astronomy
• Direct reading of charge multipliers with a self-triggering CMOS analog chip with 105k pixels at 50 micron pitch
• X-ray Polarimetry: a new window on the high energy sky

Cited by in corpus (10)

• Design, Construction, and Test of the Gas Pixel Detectors for the IXPE Mission
• Re-detection and a Possible Time Variation of Soft X-ray Polarisation from the Crab
• X-ray spectra and polarization from magnetar candidates
• A Study of background for IXPE
• XPOL-III: a New-Generation VLSI CMOS ASIC for High-Throughput X-ray Polarimetry
• Polarisation Leakage due to Errors in Track Reconstruction in Gas Pixel Detectors
• Modeling the in-orbit background of PolarLight
• Equalizing the Pixel Response of the Imaging Photoelectric Polarimeter On-Board the IXPE Mission
• Simulation of a Xe-based X-ray Polarimeter at 10-30 keV
• A significant detection of X-ray Polarization in Sco X-1 with PolarLight and constraints on the corona geometry