Proto-DUNE PD QC/QA Initial Planning David Warner, Leon Mualem Colorado State University, Caltech 1/13/16

Outline Description of photon detector (PD) module components Component-level description of QC/QA requirement development and planned testing for current reference design PD modules  Silicon photomultipliers (SiPMs) (Leon Mualem presentation)  SiPM/mounting board assembly  Radiator plate  Wavelength shifting (WLS) light guide  Readout cable Completed PD module QC Custom-built test QC/QA apparatus QC/QA Data storage  Production travelers  Incoming materials receiving inspection records Summary/Conclusions 2

3 sensL C SiPMs Mounting PCB Radiator Plate WLS Light Guide SiPM Assembly PD Module Design

SiPM Mounting Board Assembly 4 The SiPM mounting board assembly holds 12 SiPMs (grouped in four groups of 3 SiPMs per electronics channel against the face of the WLS light guide. The design functionality is to position the SiPMs relative to the face of the light guide and provide electrical connection to the short haul readout cables Development of QC/QA requirements is currently underway at CSU, funded under wbs and Incoming material QA monitoring includes:  Electrical and mechanical inspection of PCBs  Inspection of molded mounting components QC measurements include:  Post-soldering diode check of all SiPM connections through cat 6 cable  Cryogenic testing of all SiPMs and assemblies illuminated by LEDs in LN2, including Gain vs. bias voltage Dark count rate as a function of threshold and bias voltage After pulsing rate as a function of threshold and bias voltage Proto-DUNE SiPM mounting board initial design and testing is assigned to CSU. Proto-DUNE Production assembly and testing is assigned to NIU and Caltech 12X SiPM RJ-45 Cat 6 Jack

Radiator Plate 5 The radiator plate is a 256mm X 86mm X 1.5mm thick PMMA (?) sheet coated on one side with TPB (16 per PD module) The design functionality is to convert 128nm LAr scintillation light to ~400nm light to be captured in the PD WLS light guide bar. Development of QC/QA requirements is currently underway at IU, funded under wbs lines and Incoming material QA monitoring includes:  Mechanical dimensions of PMMA blanks (go- nogo gauge) QC measurements include:  Uniformity of coating (UV LED Scan)  VUV conversion efficiency (Calibrated light source/detector) Proto-DUNE radiator plate fabrication and testing is assigned to IU.

Wavelength Shifting Bar 6 The Wavelength shifting bar is a 2094mm X 86mm X 6mm thick PS allow sheet doped with WLS dyes. The design functionality is to convert ~400 nm light to ~550nm light transportable in the PD light guide bar, and transport the light (up to the full bar length) to the SiPMs at the bar end. Development of QC/QA requirements is currently underway at IU, funded under wbs lines and Incoming material QA monitoring includes:  Mechanical dimensions of incoming cast bars (go-nogo gauge)  Attenuation length for shifted light (UV LED scan in module test dark box)  Light yield from shifted UV (UV LED scan) QC measurements include:  Quality of polished cut bar end Proto-DUNE Wavelength shifting bar fabrication and testing is assigned to IU.

Readout Cable The readout cables transport SiPM signals ~37m from the SiPMs to the readout electronics (SSPs). The cables are PTFE-insulated Cat-6 cables, with 4 individually-shielded twisted pairs per cable. The readout cables come in three sections:  “Short haul” cables, which run through the APA side tubes to the readout end of the APAs. They are variable lengths, from ~2m to ~ 0.5m, depending on the PD position in the APA  “Long haul” cables, which connect to the end of the short haul cables and run to the cryostat penetrations. They are ~20m in length.  “External” cables, which run from the cryostat penetration to the SSPs. They are ~15m in length. Development of QC/QA requirements is currently underway at ANL, funded under wbs lines and Incoming material QA monitoring includes:  End-to-end connectivity check for each cable  Check of fast-rise time signal from end to end for each cable. Proto-DUNE readout cable design and testing assigned to ANL. 7

Completed PD module QC Following assembly, PD modules will go through extensive QC testing. QC tests planned include:  Insertion of the PD module into a dummy test stand to confirm mechanical tolerances  Initial (warm) scan of the completed module illuminated with a UV LED  Cryogenic test of completed module in LN2 in CSU CDDF dewar, including operation with UV LED  Final (warm) scan of the completed module illuminated with 128nm light. Development of QC/QA requirements is currently underway at CSU, funded under wbs lines and Proto-DUNE PD module design, fabrication and testing assigned to CSU. 8

CSU Module Scanner (Warm) 9

Cycled Cryogenic SiPM / Mounting Board Test Station 10

CDDF 2.5m Test Dewar 11

QA/QA Record Keeping 12 QA/QC record keeping for Proto- DUNE will be based on the 35T experience. QA incoming materials inspection forms will be created and filled out for all PD components supplied by external vendors. QC record forms (such as the model from the 35T detector on the next slide) will be filled out for each step of assembly. All QC/QA travellers/inspection forms will have paper copies which travel with the appropriate components, as well as a (scanned?) digital form to be kept online.

35T PD “Traveller”--QC record sheet for modules 13

Proto-DUNE PD QC/QA Initial Planning the SiPM section Leon Mualem Caltech 1/13/16

SiPM testing techniques Several methods have been used by the collaboration to characterize the performance of SiPMs for DUNE and the PD system Demonstrated use of Argonne SSP system used in TallBO tests, IU tests, CSU tests  After suitable analysis, it measures AC characteristics: Gain, noise rate, crosstalk rate, afterpulsing, gain vs. Voltage Other systems under development  CAEN MCA system at CSU  Datalogger method at Caltech DC testing with LED illumination, map out I-V curve Could provide quick low-noise measurement of SiPM characteristics Leon MualemProto-DUNE QC/QA plan15

IU Tests of Cold SiPM AGING Leon MualemProto-DUNE QC/QA plan16 Several Tests of SiPM lifetime and operational stability underway at IU using SSP  Passive cold aging Cryogenic storage at bias Running since March 2015 Dune-doc-905 – no change  Active cold aging Running several SiPMs illuminated by pulser for 2 weeks to accumulate 250 years of equivalent light exposure  not accelerated aging, but long duration exposure Dune-doc-904 – no change

Caltech Datalogger Method Leon MualemProto-DUNE QC/QA plan17 Measure DC characteristic Illuminate with LED Long-term low-noise testing/monitoring possible Developing test for long term aging similar to IU illuminated aging, but with DC source Could measure SiPM gain and noise characteristics as well, depending on sensitivity and how well warm/cold tests correlate Voltage ramp with very low noise shown in top plot, down to microvolts, should be sensitive to pA of current.

SiPM QA/QC plan QA philosophy on received components  protoDune-SP Test warm AC/DC characteristics  Gain, crosstalk, breakdown voltage, Test cold AC/DC characteristics  Before and/or after mounting to PCB? TEST EVERYTHING TEST again after final mounting TEST again at CERN  There are not that many components we need to know if/when anything changes so that we can adjust plans for the first 10kT detector Leon MualemProto-DUNE QC/QA plan18

SiPM testing details Leon MualemProto-DUNE QC/QA plan19 Techniques exist that are straightforward and easily demonstrated All should be possible with the protoDUNE-SP scale of ~1000 parts to be tested/assembled. Exactly who does what, and exactly what the specifications are for the test are still uncertain Physics requirements are still needed for light yield, noise limits, etc. PD system appears to have sufficient performance of the detectors, but additional testing and simulation are required  Single PE sensitivity looks reasonable  Is energy threshold low enough?  Requirement for late light detection could impact the system

SiPM testing Details II Leon MualemProto-DUNE QC/QA plan20 QA tests for acceptance  Compare test with Mfgr Spec sheet  Use SSP or other AC signal test to test noise  Need to develop test module for connecting to unmounted SiPM?  Test once mounted to the final PCB?  Record data in database for comparison (simple as google-doc spreadsheet for 1000 items) QC on SiPM assemblies  Retest (or first test) of warm SiPMs  Test response to illumination from standard light source (monitored LED)  Record results  Retest in LN2 Don’t want the first time these go cold to be after they are sealed away.  Test apparatus, specifications and details still needs to be developed in the next year

Conclusions: Continue longterm testing processes already in progress QA/QC planning for Proto-DUNE PD detectors is well underway. Component-level description of QC/QA requirement development and planning for testing has begun for all major components  Silicone photomultipliers (IU/NIU/Caltech)  SiPM/mounting board assembly (Caltech/NIU)  Radiator plate (IU)  Wavelength shifting (WLS) light guide (IU)  Readout cable (ANL) Completed PD module QC (CSU) Custom-built test QC/QA apparatus is being planned and in most cases designed and/or fabricated. QC/QA Data storage planning has begun  Sample production travelers and coming materials receiving inspection records from 35T are being modified for Proto-DUNE  We have begun thinking about online storage of QA/QC data. QC for pre-installation PD modules and cables at CERN will be addressed in a later presentation. Final plans and who will perform all testing may be informed by LOI process 21