Development of a novel MPGD-based drift chamber for the NSCL/FRIB S800 spectrometer

TL;DR

This paper presents a new MPGD-based drift chamber designed for the NSCL/FRIB S800 spectrometer, demonstrating high-resolution tracking capabilities through extensive testing with alpha particles and heavy-ion beams.

Contribution

The development of a large-area, MPGD-based drift chamber with integrated Micromegas and M-THGEM technology for enhanced spectrometer tracking performance.

Findings

Achieved sub-millimeter position resolution in tests.

Successfully operated with high-energy heavy-ion beams.

Demonstrated compatibility with the S800 spectrometer's large acceptance.

Abstract

The performance of a novel tracking detector developed for the focal plane of the NSCL/FRIB S800 magnetic spectrometer is presented. The detector comprises a large-area drift chamber equipped with a hybrid Micro-Pattern Gaseous Detector (MPGD)-based readout. The latter consists of a position-sensitive Micromegas detector preceded by a two-layer M-THGEM multiplier as a pre-amplification stage. The signals from the Micromegas readout are processed by a data acquisition system based on the General Electronics for TPC (GET). The drift chamber has an effective area of around 60x30 cm^2, which matches to the very large acceptance of the S800 spectrometer. This work discusses in detail the results of performance evaluation tests carried out with a low-energy alpha-particles source and with high-energy heavy-ion beams with the detector installed at the S800 focal plane. In this latter case, the detector was irradiated with a 150 MeV/u 78Kr36+ beam as well as a heavy-ion fragmentation cocktail beam produced by the 78Kr36+ beam impinging on a thin beryllium target. Sub-millimeter position resolution is obtained in both dispersive and non-dispersive directions.