At present, the HV consortium is gathering institutions to participate in the design, construction and assembly of the HV systems for both SP modules and DP modules. The consortium needs to grow in the near future, and it hopes to attract new institutions, in particular from EU to balance USA participation with additional international participants.
The consortium management structure currently includes a consortium leader from CERN, a techincal lead from BNL, and technical design report (TDR) editors from CERN and UTA. In the current HV consortium organization, each institution is naturally assuming the same respon- sibilities it had for ProtoDUNE-DP. The consortium is organized into six working groups (WG) that are addressing the design and R&D phases, and the hardware production and installation.
Chapter 4: High Voltage System 4–97
Table 4.2: HV Consortium Participants
Institution
EU: CERN
USA: Argonne National Lab USA: Brookhaven National Lab
USA: University of California (Berkeley) USA: University of California (Davis) USA: Fermi National Accelerator Lab USA: University of Houston
USA: Kansas State University
USA: Lawrence Berkeley National Lab USA: Louisiana State University
USA: South Dakota School of Mines and Technology USA: Stony Brook University
USA: University of Texas (Arlington) USA: Virginia Tech.
USA: College of William and Mary
• WG1. Design optimization for SP and DP; assembly, system integration, detector simulation, physics requirements for monitoring and calibrations.
• WG2. R&D activities and facilities.
• WG3. SP-CPA: Procurement, in situ QC, resistive panels, frame strips, electrical connections of CPA modules, QC, assembly, shipment to assembly site / QC.
• WG4. DP Cathode. • WG5. FC modules.
• WG6. HV supply and filtering, HV power supply and cable procurement, R&D tests, filtering and receptacle design and tests.
Merging of SP and DP groups is envisaged for the working groups where synergies are being identified: HV feedthroughs, voltage dividers, aluminum profiles, FRP beams, and assembly in- frastructures.
4.9.2
Planning Assumptions
The present baseline design for all elements of the HV system for DP module strictly follows the ProtoDUNE-DP design as it has been produced and is being assembled. It is also assumed that no major issues in the HV system operation of ProtoDUNE-DP will be encountered and therefore
that the basic HV system concepts are sound.
However some design modifications and simplifications must be implemented to take into account the doubled drift distance, implying an increase in HV delivery to the cathode from −300 kV to −600 kV.
The DP HV system distribution and the related cathode structure still require intense R&D, given the unprecedented value of the required HV (−600 kV). The related results could lead to revision of design details such as the shape of the cathode elements and of the GP structures, the distance from the cryostat walls, the distance between the cathode and the GP protecting the PDs, and resistive connections of the cathode modules. It is important to ensure that the E field intensity in the LAr is below the critical value of about 30 kV/cm everywhere and that the energy stored in the FC is not released catastrophically to the detector membrane.
As for the SP module, ProtoDUNE-SP serves as the test-bed for understanding and optimizing detector element assembly, installation sequence, and integration as well as requirements in human resources, space and tooling, and schedule.
Chapter 5: Photon Detection System 5–99
Chapter 5
Photon Detection System
5.1
Overview
5.1.1
Introduction
The dual-phase (DP) photon detection system (PDS) primarily serves three purposes. It provides the trigger for non-beam events; it enables determination of the event absolute time for beam and non-beam events; and it enables calorimetric measurements. It is essential to ensure that the DP PDS is optimized for the full DUNE physics program. In particular, low-energy signals like supernova neutrino burst (SNB) neutrinos and multi-messenger astronomy, other low-energy signals, and proton decay, impose more stringent requirements on PDS performance than the primarily higher energy, beam-synchronous, neutrino oscillation physics. The final specifications of the system will be determined so as to achieve these physics requirements. A number of scientific and technical issues impact the DP PDS and SP PDS in a similar way, and the consortia for these two systems cooperate closely. See Volume 2: Single-Phase Module, Chapter 5 for details on the SP PDS.
This chapter concentrates on direct projection of the ProtoDUNE-DP design to the DUNE scale. The optimization and final design of the DP PDS is driven by the ProtoDUNE-DP [6] data and simulation studies.
The chapter begins with an overview of the system in Section 5.1. Section 5.2 describes the photosensors, namely photomultiplier tubes (PMTs) and the related high voltage (HV) system, wavelength shifters and light collectors. The mechanics associated with the PMTs is described in Section 5.3, and the readout electronics in 5.4. Section 5.5 details the photon calibration system to monitor the PMT gain and stability. Then, the photon detector (PD) performance is described in Section 5.6, and the operations in Section 5.7. Interfaces with other subsystems are described in Section 5.8. Section 5.9 includes the installation, integration and commissioning plans. The quality control (QC) procedures are outlined in Section 5.10. The main safety issues to consider are
specified in Section 5.11. To finish, the management and organization is described in Section 5.12.