The Sparse Readout RIGEL Application Specific Integrated Circuit for Pixel Silicon Drift Detectors in Soft X-Ray Imaging Space Applications

TL;DR

This paper introduces RIGEL, a specialized ASIC for sparse readout of Silicon Pixel Drift Detectors, achieving high spectroscopic resolution suitable for space-based soft X-ray imaging.

Contribution

The paper presents the design and characterization of a novel ASIC, RIGEL, optimized for space applications with low noise, low power, and high resolution for pixel silicon drift detectors.

Findings

Achieved 55 eV FWHM at 5.9 keV with a 4x4 PixDD prototype.

Supported a charge range up to 30 keV with multiple peaking times.

Low power consumption of less than 550 μW per channel.

Abstract

An Application Specific Integrated Circuit (ASIC), called RIGEL, designed for the sparse readout of a Silicon Pixel Drift Detector (PixDD) for space applications is presented.The low leakage current (less than 1 pA at +20 {\deg}C) and anode capacitance (less than 40 fF) of each pixel (300 um x 300 um) of the detector, combined with a low-noise electronics readout, allow to reach a high spectroscopic resolution performance even at room temperature. The RIGEL ASIC front-end architecture is composed by a 2-D matrix of 128 readout pixel cells (RPCs), arranged to host, in a 300 um-sided square area, a central octagonal pad (for the PixDD anode bump-bonding), and the full-analog processing chain, providing a full-shaped and stretched signal. In the chip periphery, the back-end electronics features 16 integrated 10-bits Wilkinson ADCs, the configuration register and a trigger management circuit. The characterization of a single RPC has been carried out whose features are: eight selectable peaking times from 0.5 us to 5 us, an input charge range equivalent to 30 keV, and a power consumption of less than 550 uW per channel. The RPC has been tested also with a 4x4 prototype PixDD and 167 eV Full Width at Half Maximum (FWHM) at the 5.9 keV line of 55Fe at 0{\deg}C and 1.8 us of peaking time has been measured.