Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter.pdf

Electron-Ion Collider, Brookhaven National Laboratory

Doc No. EIC-DET-SPC-020 Author: Alexander Bazilevsky Effective Date: January 16, 2024 Review Frequency: N/A

Specification Title: Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter Revision: 00

TECHNICAL SPECIFICATION

for PbWO4 Crystals for the Backward Electromagnetic Calorimeter

Quality Classification: A-3

Prepared By:

_________________________________ Date: __________________ Alexander Bazilevsky, CAM

Tanja Horn, DSL

Reviewed By:

Edward Cheswick, Quality Representative

Marcel Romero, Procurement Liaison Engineer

Chuck Schaefer, ESH Manager

Approved By:

Elke Aschenauer, Level 2 Manager

DocuSign Envelope ID: EC1DAD76-5A30-46B0-8A5C-B786D24F25F5

1/16/2024

1/16/2024

1/16/2024

1/23/2024

1/16/2024

1/23/2024

Doc No. EIC-DET-SPC-020 Author: Alexander Bazilevsky Effective Date: January 16, 2024 Review Frequency: N/A

Specification Title: Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter Revision: 00

This page intentionally left blank, to accommodate back-to-back printing.

Doc No. EIC-DET-SPC-020 Author: Alexander Bazilevsky Effective Date: January 16, 2024 Review Frequency: N/A

Specification Title: Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter Revision: 00

REVISION HISTORY

Revision # Effective Date Summary of Change

00 1/16/2024 Initial Release

Doc No. EIC-DET-SPC-020 Author: Alexander Bazilevsky Effective Date: January 16, 2024 Review Frequency: N/A

Specification Title: Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter Revision: 00

TABLE OF CONTENTS

1 BACKGROUND

1.1 Background

2 APPLICABLE DOCUMENTS

3 REQUIREMENTS

3.1 Technical/Performance Characteristics

3.2 Materials

3.3 Environment, Safety and Health

4 VERIFICATION

4.1 Classification of Inspections

Doc No. EIC-DET-SPC-020 Author: Alexander Bazilevsky Effective Date: January 16, 2024 Review Frequency: N/A

Specification Title: Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter Revision: 00

LIST OF ACRONYMS

BNL Brookhaven National Laboratory BSA Brookhaven Science Associates DOE Department Of Energy EIC Electron-Ion Collider ESH Environment, Safety and Health ESR Electron Storage Ring HSR Hadron Storage Ring

PBWO4

RHIC

Lead Tungstate Relativistic Heavy Ion Collider

RCS Rapid Cycling Synchrotron

Doc No. EIC-DET-SPC-020 Author: Alexander Bazilevsky Effective Date: January 16, 2024 Review Frequency: N/A

Specification Title: Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter Revision: 00

Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter

1 BACKGROUND

The Electron-Ion Collider (EIC) is a Nuclear Physics facility being built at the United States (U.S).

Department of Energy’s (DOE) Brookhaven National Laboratory (BNL). The EIC will create intense beams of relativistic energy electrons and ions in opposing particle storage rings that will be brought into collision in a large experimental detector. This will provide insight into the internal structure of protons and neutrons and the gluelike force that holds them together.

1.1 Background

The EIC Project includes one interaction region, with an allowance for a second, and one detector. The EIC detector is being designed as a hermetic, general-purpose detector. It will be an approximately 10-meter-long cylindrical barrel detector with additional instrumentation that extends to up to 45m in each direction down the EIC beamline. It will use cutting-edge technologies to detect particles created in collisions between high energy electrons and protons or heavy ions (the nuclei of larger atoms) moving close to the speed of light. It will be based on a

1.7 Tesla superconducting magnet for curving the trajectories of charged particles created in these collisions and will include high precision tracking and particle identification systems to measure and identify charged particles, electromagnetic calorimeters to measure and identify electromagnetic particles, and hadronic calorimeters to allow for high precision jet (a collimated spray of particles) measurements.

The Backward Electromagnetic Calorimeter role in the EIC detector is the high precision measurements of scattered electrons to determine the event kinematics in inclusive Deep Inelastic Scattering events, and final state photons. Its design is based on high quality PbWO4 crystals, which convert the energy of the impact electrons and photons into light, subsequently detected by photo sensors.

2 APPLICABLE DOCUMENTS

None.

Doc No. EIC-DET-SPC-020 Author: Alexander Bazilevsky Effective Date: January 16, 2024 Review Frequency: N/A

Specification Title: Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter Revision: 00

3 REQUIREMENTS

3.1 Technical/Performance Characteristics

Parameter Unit Length cm 20 Sides cm 2 Tolerance in Length µm ≤±150 Tolerance in Sides µm ≤±50 Surface polished, roughness Ra µm <0.02 Perpendicularity, parallelism mm ≤0.02 Surface flatness mm ≤0.02 Tolerance in Rectangularity degrees ≤0.1 Emission peak nm 420 Longitudinal Transmission at λ=360nm λ=420nm λ=600nm

>35 >60 >70

Inhomogeneity of Transverse Transmission ∆λ at T=50% nm ≤5

Light Yield at 18degC within gate 100ns pe/MeV >15 Light Yield (100ns)/Light Yield(1 µ s) % ≥95 Light Yield uniformity between blocks % 10

Transverse Transmission and Light Yield uniformity along crystal

% 10

Radiation-induced absorption coefficient dk at 18degC for integral dose 30Gy at λ=420nm m-1 ≤1.5

Mean value of dk m-1 ≤0.75

3.2 Materials

Raw material quality shall be commensurate with high quality crystals.

Doc No. EIC-DET-SPC-020 Author: Alexander Bazilevsky Effective Date: January 16, 2024 Review Frequency: N/A

Specification Title: Technical Specification for PbWO4 Crystals for the Backward Electromagnetic Calorimeter Revision: 00

3.3 Environment, Safety and Health

Identification of hazards, and their mitigation, during all stages of the life of the Equipment including; installation, commissioning, operation, maintenance, and repair. Identification of means to eliminate or manage each hazard shall be provided based on the following hierarchy:

• Eliminate the hazard, or

• Substitute with something less hazardous, or

• Engineer – mitigate the severity of the hazard, or

• User Personal Protective Equipment (least desirable).

4 VERIFICATION

Appropriate inspection/tests shall be performed to ensure crystals conform to all requirements in section 3 of this specification.

4.1 Classification of Inspections

Items covered by this specification shall be subjected to the following tests to determine compliance with all applicable requirements:

4.1.1. Preproduction Tests (First Article).

For this purpose, 140 crystals meeting this specification shall be requested by BSA.

4.1.2. Acceptance Tests.

The approval to proceed into production shall be granted based on the results of the tests with first article crystals coordinated by BSA and Detector Subsystem Leader.