PSD14: International Conference on Position Sensitive Detectors

Characterization and Application of the First Prototype of HEROC: An Analog Readout ASIC for Position-Sensitive Helium-3 Tube Neutron Detectors

Not scheduled

20m

Mile End Campus: Graduate Centre Foyer and Peston Lecture Theatre (Queen Mary University of London, London, UK)

Poster Detectors for Neutron Facilities

Speaker

Jiayi REN

Description

The China Spallation Neutron Source (CSNS) is undergoing an upgrade to CSNS-II, targeting an increase in proton beam power to 500 kW. This upgrade imposes stringent requirements on neutron detector readout electronics, including operation under vacuum conditions, higher counting rates, improved spatial resolution, and reduced power consumption. Conventional discrete-component front-end electronics suffer from high power dissipation and limited performance, making them unsuitable for these applications.

To address these challenges, we have developed a prototype application-specific integrated circuit (ASIC), named HEROC (HElium-3 ReadOut Circuits), for position-sensitive Helium-3 tube neutron detectors. Each channel integrates a charge-sensitive amplifier, pole-zero cancellation, shaping amplifier, and output buffer, providing a compact and low-power analog front-end solution. The fabricated 8-channel ASIC demonstrates an input dynamic range from 10 fC to 1.5 pC and supports counting rates up to 500 kHz. Electrical measurements show an equivalent noise charge of 1130 electrons at 15 pF, with power consumption below 9.9 mW per channel, corresponding to an approximate 90% reduction compared to the discrete-component front-end electronics used in CSNS-I.

The ASIC was validated through vacuum and neutron beam tests. Stable operation was achieved under vacuum with negligible temperature increase. Beam tests at CSNS produced clear charge spectra and time-of-flight distributions, and an optimal position resolution of 6 mm was obtained. The system demonstrated stable operation at counting rates up to 125 kHz during beam measurements. The results indicate that the HEROC ASIC is a promising solution for low-power, vacuum-compatible neutron detector readout in CSNS-II spectrometers. The ASIC-based detector readout system has already been successfully deployed and is operating stably at the first CSNS-II beamline, the Neutron Technology Development Beamline. It is planned for further implementation in additional CSNS-II spectrometers.