Speaker
Description
The ePIC detector will be the first detector at the upcoming Electron-Ion Collider (EIC)[1] at Brookhaven National Lab. The design of the detector is determined by the various physics goals of the EIC program, which include addressing the origin of the nucleon spin, the three-dimensional structure of the nucleon, the study of saturation effects, and the study of hadronisation. This ambitious scientific program imposes stringent requirements on the tracking system needed for the measurement of the scattered electron and charged particles produced in the collisions at the EIC.
The ePIC tracking system combines Silicon trackers with Micro Pattern Gaseous Detectors (MPGDs). The Endcap Trackers are designed to cover the pseudo-rapidity region $|\eta| > 2$, one positioned in the leptonic region and the other in the hadronic region. Each of them is composed of a pairs of GEM$\mathrm{\mu}$-RWELL[2,3], a hybrid detector capable of very stable operation at gas gain larger than $2\times10^4$. This is accomplished through the coupling of a single GEM pre-amplification layer and a standard $\mathrm{\mu}$-RWELL. The R&D has been introduced in collaboration with the INFN-LNF group, which is studying its timing performance for the LHCb Phase II upgrade.
As tracker, each disk is engineered to meet stringent performance requirements, including a time resolution of $10$ ns, a material budget of approximately $1$% $\mathrm{X_0}$, and most of all a spatial resolution of $150$ $\mathrm{\mu}$m, and a single detector efficiency of $96–97$%, corresponding to a combined efficiency for the two layer of $92–94$%. The addition to the GEM pre-amplification is necessary as a solution for the typical high gain required for satisfying such performance for angular tracks.
As part of this effort, a recent test beam campaign was conducted in November 2024 at the PS-T10 East Area at CERN. This test aimed to evaluate the spatial resolution and detection efficiency under varying angles between the incident beam and the detector surface, ensuring compatibility with ePIC's operational requirements.
In this talk, I will provide an overview of the EPIC detector, with a focus on the Endcap Trackers and their integration into the broader tracking system. I will then delve into the GEM$\mathrm{\mu}$-RWELL technology and the key results obtained.
[1] R. Abdul Khalek et al. Nuclear Physics A, 1026:122447, 2022.
[2] G. Bencivenni et al. JINST, 10:P02008, 2015.
[3] L. Shekhtman et al. NIM-A, 936:401–404, 2019.
