Development and study of an imaging detector based on high-position resolution THGEM

Abstract

Introduction

THick Gaseous Electron Multiplier (THGEM) has many advantages while the moderate position resolution is regarded as the main inferiority comparing with the traditional GEM, so this limits the applications of THGEM, such as X-ray imaging and charge particle tracking.

Materials and methods

By improving the production techniques, THGEMs with smaller pitch and hole diameter can be made, i.e., 0.4 and 0.15 mm by mechanical drilling, and 0.3 and 0.1 mm by laser etching, respectively. Based on the new THGEMs, a two-dimensional imaging detector with 50$\times$50mm sensitive area was developed for 0.1 $\sim$ 50 MeV low-energy electrons detection and reaching better than 100$\upmu$m position resolution (sigma). At the same time, a set of front-end electronics was developed based on homemade ASIC chips, i.e., Charge Amplifier and Shaping Amplifier for GEM (CASAGEM), and applied successfully to the detector.

Conclusion

The X-ray and beam tests results indicate that both detector and Front End Electronics (FEE) worked well, and the position resolution achieved 74.9$\upmu$m by using the charge center-of-gravity method. This indicates that the high-position resolution THGEM is promising for imaging and tracking application.