Characterization of Large GEM Module for the Tracker at Jlab Hall A

F Mammoliti,V Bellin,M.C Sutera,P Musico,F Librizzi,L Re,E Cisbani,F Noto,R Perrino,G Giardina,M Battaglieri,G Mandaglio,S Eidelman,G Venanzoni

doi:10.1051/epjconf/20159601023

Abstract

A new Large-Acceptance Forward Angle Spectrometer (Super BigBite) is under development at JLab/Hall A for the upcoming experiments in Hall A at Jefferson Lab where a longitudinally polarized electron beam of 11 GeV is now available. This beam, combined with innovative polarized targets will provided luminosity up to 1039 /(s·cm 2 ) opening exciting opportunities to investigate unexplored aspects of the inner structure of the nucleon. The tracker of this new apparatus is based on the Gas Electron Multiplier (GEM) technology, which has been chosen to optimize cost/performance, position resolution and to meet the high hit rate (>1 MHz/cm 2 ). The first GEM detector modules, designed and built by the INFN Collaboration JLAB12, were tested at the DESY test beam facility in Hamburg, by using an electron beam with energy ranging from 2.0 to 6.0 GeV. In particular, three 40x50 cm 2 GEM chambers were equipped with a new implementation of the APV25 readout chip. Measurements were performed at different impact points and angles between the electron beam and the plane of the GEM chambers, with one large chamber in a solenoid magnetic field up to 500 Gauss. In this paper we present the technical features of the tracker and comment on the presently achieved performance.

Highlights

The new spectrometer will consist of a dipole magnet with field integral up to 3 T, a primary charged particle tracker, 2 identical proton polarimeters, and an hadron calorimeter
EPJ Web of Conferences and of the Gas Electron Multiplier (GEM) detector will be presented and, we will discuss about the results of the test performed at DESY
The module is equipped with the APV25 electronics and 18 front-end cards are located behind the 4 rectangular backplanes that sit along the 4 sides of the module

Summary

Introduction

The new spectrometer will consist of a dipole magnet with field integral up to 3 T (it will operate at about 2 T ), a primary charged particle tracker (first tracker), 2 identical proton polarimeters (made of a Carbon analyzer and large tracker), and an hadron calorimeter. SBS will initially serve 4 experiments [3] dedicated to the study of the nucleon structure in terms of elastic electromagnetic form factors at high 4-momentum transfer Q2 up to 15 GeV2 and of transverse momentum distributions of the quarks in the SIDIS (Semi Inclusive Deep Inelastic Scattering) region. The tracking systems of SBS will be mainly based on GEM chambers. The main features of the SBS tracker. EPJ Web of Conferences and of the GEM detector will be presented and, we will discuss about the results of the test performed at DESY

SBS Tracker and GEM Detector

Data Analysis and Discussion

Findings

Conclusions