1. Matthew Bomberger1, Francisco Izquierdo1, Aiwu Zhang2
Design and Construction of a Large-Area GEM for a Future Electron Ion Collider
Matthew Bomberger1, Francisco Izquierdo1, Aiwu Zhang2
Faculty Advisor: 1Marcus Hohlmann, Dept of Physics, 1Florida Institute of Technology and 2Brookhaven National Lab
Abstract
The design of a 1-meter long gas electron multiplier (GEM) for a future electron ion collider (EIC) is proposed such that the material in the active region of the detector is reduced. This is achieved by reducing the support boards to frames and transferring the drift and readout electronics to separate foils. Although interactions between incident particles and the detector material is reduced, the material, thickness, and width of the frames are determined to be a carbon fiber composite, 4 mm, and 35.5 mm, respectively.
BeAST Detector
Construction
Materials:
Use of IM7 high modulus and 090 standard unidirectional carbon fiber fabrics to get as close as possible to the model
Araldite epoxy was utilized since it has known outgassing properties
Mixing ratio: 5 epoxy to 2 hardener [7]
A frame portion was analyzed in order to determine the Young’s and shear moduli of the composite; it deflected 1.43 mm at an applied force of 70 N
According to the trends generated using Inventor, the Young’s and shear moduli at that value are respectively 354 GPa and 9 GPa
Background
GEMs are used for detecting the positions of charged particles
In high-energy collisions found in particle colliders, muons are produced and can be detected using GEMs [1-3].
An EIC project is being proposed to be built in the US in order to rigorously test quantum chromodynamics (QCD)
GEMs need to be used to track charge particles produced from ion collisions [4-5]
GEM Location [6]
Analysis
Multiple deformation studies determined the material, thickness, and width of the frames
Material: M55 unidirectional carbon fiber (M55UDCF)
Thickness: 4 mm
Width: 35.5 mm, respectively
Design
Drift and readout structures are placed on foils and support frames are used [5]
The frames must deform between 1 and 2 mm in each direction so that the foils do not sag.
1.43 mm
Production of partial frame:
Wooden mold was manufactured
Carbon steel rods were cut down to 1 inch pins so that the holes could be molded into it.
Drift Support Frame
Pullout Post mm mm
2 mm
Drift Foil mm
Step 1: Pins placed in mold
Step 2: Add carbon fiber and epoxy
Step 3: Make vacuum bag and cure mm z y
Conclusion
Using frames for support is valid
Preliminary experimental results conclude that the frames will perform well when constructed
This encourages the authors to produce a full-scale prototype of the detector
GEM Foils mm x mm
R/O Foil
Acknowledgements
We would like to thank Structural Composites, Inc. for helping us manufacture the frames. This research is supported by Brookhaven National Laboratory under the EIC eRD-6 consortium.
References
[1] Sauli, F., 1997, “GEM: A new concept for electron amplification in gas detectors,” Nuclear Instruments and Methods in Physics Research A, 386(2-3), pp
[2] C. Altunbas, et al., 2002, “Construction, test and commissioning of the triple-GEM tracking detector for compass,” Nuclear Instruments and Methods in Physics Research A, 490(1-2), pp
[3] CMS GEM collaboration, 2015, “CMS Technical Design Report for the Muon Endcap GEM Upgrade,” CERN-LHCC , CMS-TDR-013, ISBN
[4] A. Accardi, et al., 2012, “Electron Ion Collider: The Next QCD Frontier – Understanding the glue that binds us all,” Also known as the EIC White Paper, arXiv: (
[5] A. Zhang, et al., Nov. 24, 2015, “R&D on GEM detectors for forward tracking at a future Electron-Ion Collider,” Proc. Of IEEE Nuclear Science Symposium, San Diego, CA, arXiv:
[6] M. Hohlmann, March 2017, “Large GEM Detectors for Tracking at Forward Rapidities,” RHIC Spin Collaboration Meeting, Brookhaven National Laboratory (
[7] A. Quintero, July 2009, “Assembly 30 cm x 30 cm GEM detectors,” thesis, Florida Institute of Technology (
R/O Support Frame