Large Area X-ray Proportional Counter (LAXPC) Instrument on AstroSat

TL;DR

The LAXPC instrument on AstroSat provides high time resolution X-ray observations across a broad energy range, enabling detailed timing and spectral studies of X-ray sources with extensive calibration and simulation efforts.

Contribution

This paper introduces the design, calibration, and capabilities of the LAXPC instrument on AstroSat, highlighting its large area, broad energy coverage, and high time resolution for X-ray astronomy.

Findings

Successful calibration of LAXPC detectors.

Demonstrated detection efficiency >50% above 30 keV.

Validated instrument capabilities through payload verification.

Abstract

Large Area X-ray Proportional Counter (LAXPC) is one of the major AstroSat payloads. LAXPC instrument will provide high time resolution X-ray observations in 3 to 80 keV energy band with moderate energy resolution. A cluster of three co-aligned identical LAXPC detectors is used in AstroSat to provide large collection area of more than 6000 cm2 . The large detection volume (15 cm depth) filled with xenon gas at about 2 atmosphere pressure, results in detection efficiency greater than 50%, above 30 keV. With its broad energy range and fine time resolution (10 microsecond), LAXPC instrument is well suited for timing and spectral studies of a wide variety of known and transient X-ray sources in the sky. We have done extensive calibration of all LAXPC detectors using radioactive sources as well as GEANT4 simulation of LAXPC detectors. We describe in brief some of the results obtained during the payload verification phase along with LXAPC capabilities.