Presentation Title

Optimization of geometry and a radiation damage study of acrylic light guides

Faculty Mentor

Craig Woody, Sean Stoll

Start Date

18-11-2017 10:00 AM

End Date

18-11-2017 11:00 AM

Location

BSC-Ursa Minor 127

Session

Poster 1

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

The Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) detector for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is undergoing a major upgrade under the project name sPHENIX. Among the proposed upgrades is a new electromagnetic (EM) calorimeter which measures the energy of electrons and photons created from heavy-ion collision events. A critical component of the calorimeter design is the acrylic light guides. This part is the last step in directing 450 nm scintillation light onto Silicon Photomultipliers (SiPMs) where the light is converted to an electronic signal. The shape and material of these light guides are both important considerations to achieve maximum uniformity and efficiency of the detector. In order to improve light guide-light guide boundary efficiency, a 2 mm extension normal to the collection face is considered. The addition of the step showed a slight improvement on the boundary efficiency, and it could offer other useful manufacturing benefits. In addition to geometric concerns, the current choice for the light guide material, acrylic, is known to be susceptible to radiation damage. A study is performed to compare how ultraviolet-transmitting (UVT) acrylic compares to non-UVT acrylic under increasing doses of gamma radiation. Two possible manufacturing methods, resin-casting and injection-molding, are also considered as they could have different effects on the radiation hardness of the plastic. Results show that UVT acrylic is the better choice for the transmission of the 450 nm scintillation light, up to a gamma radiation dose of 1 Mrad. There is also evidence that using a more gentle production process, such as resin-casting instead of injection-molding, slightly improves the resistance to radiation damage.

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Nov 18th, 10:00 AM Nov 18th, 11:00 AM

Optimization of geometry and a radiation damage study of acrylic light guides

BSC-Ursa Minor 127

The Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) detector for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is undergoing a major upgrade under the project name sPHENIX. Among the proposed upgrades is a new electromagnetic (EM) calorimeter which measures the energy of electrons and photons created from heavy-ion collision events. A critical component of the calorimeter design is the acrylic light guides. This part is the last step in directing 450 nm scintillation light onto Silicon Photomultipliers (SiPMs) where the light is converted to an electronic signal. The shape and material of these light guides are both important considerations to achieve maximum uniformity and efficiency of the detector. In order to improve light guide-light guide boundary efficiency, a 2 mm extension normal to the collection face is considered. The addition of the step showed a slight improvement on the boundary efficiency, and it could offer other useful manufacturing benefits. In addition to geometric concerns, the current choice for the light guide material, acrylic, is known to be susceptible to radiation damage. A study is performed to compare how ultraviolet-transmitting (UVT) acrylic compares to non-UVT acrylic under increasing doses of gamma radiation. Two possible manufacturing methods, resin-casting and injection-molding, are also considered as they could have different effects on the radiation hardness of the plastic. Results show that UVT acrylic is the better choice for the transmission of the 450 nm scintillation light, up to a gamma radiation dose of 1 Mrad. There is also evidence that using a more gentle production process, such as resin-casting instead of injection-molding, slightly improves the resistance to radiation damage.