DOM Integration Meeting D. Vivolo - DOM Integration Meeting 06 September 2017 Daniele Vivolo INFN Section of Naples D. Vivolo - DOM Integration Meeting 06/09/17

D. Vivolo - DOM Integration Meeting Documentation Most of DOM Integration Documentation has been prepared for the DOM Integration review of last December. All files are stored on GD. All the documents are included in a MASTER DOCUMENT File name is KM3NeT_DOM_2016_002-DOM_Integration_Documents Current version: v5 This document lists the applicable and reference documents for the integration of Digital Optical Modules (DOMs) of KM3NeT Phase-1. Applicable Documents Reference Documents For each document the filename on GD, the version number and the last DCR are reported D. Vivolo - DOM Integration Meeting 06/09/17

KM3NeT_DOM_2016_002-DOM_Integration_Documents v5 DOM Integration Master document: APPLICABLE documents KM3NeT_DOM_2016_002-DOM_Integration_Documents v5 DOM Integration Procedure DOM Description of Components DOM Testing DOM Exploded View DOM Integration Tools Quality plan DOM Functional Test Sheet DOM Product Registration System DOM Integration Plan DOM Acceptance Test Sheet Pressure gauge calibration procedure NCR (Non Conformity Report) form Fixing_PMT integration and cabling mistakes DCR (Design Change Request) form D. Vivolo - DOM Integration Meeting 06/09/17

KM3NeT_DOM_2016_002-DOM_Integration_Documents v5 DOM Integration Master document: APPLICABLE documents KM3NeT_DOM_2016_002-DOM_Integration_Documents v5 updated, to be released to be updated ready, to be included in the new DOM site doc no update needed no update possible DOM Integration Procedure DOM Description of Components DOM Testing DOM Exploded View DOM Integration Tools Quality plan DOM Functional Test Sheet DOM Product Registration System DOM Integration Plan DOM Acceptance Test Sheet Pressure gauge calibration procedure NCR (Non Conformity Report) form Fixing_PMT integration and cabling mistakes DCR (Design Change Request) form D. Vivolo - DOM Integration Meeting 06/09/17

Updated files, to be released DOM Integration Master document: APPLICABLE documents Updated files, to be released DOM Integration Procedure Current Version: 5 File Name: KM3NeT_INT_2015_008-PRO_DOM_Integration_Procedure_v5.xlsx Last Update: Nov. 2016 DCR: KM3NeT_QA_2017_106-DCR-NAP_004_DOM_Integration_Procedure_v1 List of major changes: AHRS/Compass calibration values check before CLB installation Added references to new documents New Cooling bar New cooling mushroom Added reference to new Functional and Acceptance test sheets Updated tools document Warning about DOM handling during gel pouring New version: almost done, it will be released TODAY (the corresponding DCR has been approved) Still missing: AHRS/Compass check and DOM closure Notes: all changes have been discussed (and agreed) both during SC and DOM integration meetings. Included indications by Frank. D. Vivolo - DOM Integration Meeting 06/09/17

Updated files, to be released DOM Integration Master document: APPLICABLE documents Updated files, to be released DOM Description of components Current Version: 3 File Name: KM3NeT_INT_2016_006-DOM_Description_Of_Components_v3.docx Last Update: N/A DCR: KM3NeT_QA_2017_107-DCR-NAP_005_DOM_Integration_Tools_v1 List of changes: New Cooling bar New version: this file will be included in the upcoming DOM Integration Sites document. The corresponding part has already been completed. 100% Functional test sheet Current Version: 8 File Name: KM3NeT_DOM_2016_008-DOM_Functional_Test_Sheet_v8.xlsx Last Update: Nov. 2016 DCR: KM3NeT_QA_2017_105-DCR-NAP_003_DOM_Functional_Test_v1 List of changes: FPGA temperature lowered to 40°C due to failing acceptance tests New version: already done, it will be released TODAY (the corresponding DCR has been approved) D. Vivolo - DOM Integration Meeting 06/09/17

Updated files, to be released DOM Integration Master document: APPLICABLE documents Updated files, to be released Acceptance test sheet Current Version: 8 File Name: KM3NeT_DOM_2016_008-DOM_Functional_Test_Sheet_v8.xlsx Last Update: Nov. 2016 DCR: KM3NeT_QA_2017_104-DCR-NAP_002_DOM_Acceptance_test_v1 List of changes: AHRS FW version field added New Calibration document reference New version is not yet available. The final decision on the corresponding DCR is suspended Discussion about the DCR has not been completed. Investigation is still ongoing. Based on PMT test statistics, the PMT group suggested to set the dark counts limit during the acceptance test to 10kcps Current DOM production in Nikhef is done with Erlangen PMTs (not tested). Many NCRs around. In order to take into account this, the following proposal has been submitted to the SC: Dark noise limit during acceptance test set to 10kcps verification of “tunability”: enlarge the acceptance interval Investigation for a final decision has been completed, updates will come soon. D. Vivolo - DOM Integration Meeting 06/09/17

Proposal for NEW DOM Acceptance criteria Email sent to the DOM-INT mailing list last 06 August. Motivation: with the upcoming (and current) DOM production based on the integration of non-tested PMTs, a definition of new criteria for DOM acceptance tests is mandatory it is inadequate to keep the criteria used in the past, and this is confirmed by the large number of NCRs recently raised about dark rates and ToTs. Method: an analysis of the 7000 PMTs tested in the darkbox facility in Naples has been performed Preliminary: use the information available for tested PMTs in order to respect the constraint to allow up to three "bad" PMTs per DOM the assumption is that being all the non-tested PMTs belonging to the same batch of the 7000 tested PMTs the features of PMTs to be integrated are well described by the tested sample. Remark: With the use of untested PMTs, no screening on "bad" PMTs (red and yellow, in the triage coding adopted by KM3NeT) is possible. The percentage of red PMTs has been calculated to be about 3.5%, this means that on average we expect about one red PMT per DOM. D. Vivolo - DOM Integration Meeting 06/09/17

Proposal for NEW DOM Acceptance criteria DARK NOISE Current criteria: the current acceptance criteria for PMTs integrated in DOMs is 3500cps. This value corresponds to a dark count limit of 2000cps in the darkbox, taken into account the additional contribution of DOM glass after integration. Constraint: The duration of the acceptance test is 4 hours and this will be set as a constraint. The reason is that keeping this duration it will be possible in all the DOM integration sites to do (in optimal conditions) 2 acceptance tests per day per greenbox. Analysis: all the 7000 tested PMTs have been taken into account (i.e. also PMTs that at the first test were tagged as red or yellow) Reason: from now on no screening will be available, therefore in DOMs also red and yellow PMTs will be integrated. Both yellow and red PMTs have been re-tested, so for them more tests are available. Anyway, from now on the PMTs will be tested only once (inside DOMs), therefore only the first tests can be taken as a benchmark. the duration of the tests of the 7000 PMTs have been variable, therefore the final value of the dark noises correspond to an unknown test duration. In addition, different pre-darkening conditions for the 7000 PMTs are possible. This has a strong impact on the dark noise measurements. In order to define the new criterium, it has been analyzed the dark noise of all the 7000 tested PMTs. In particular, it has been plotted the fraction of PMTs having a final dark noise rate between 0 and 2000cps as a function of the first dark noise measured after 4 hours. D. Vivolo - DOM Integration Meeting 06/09/17

Proposal for NEW DOM Acceptance criteria DARK NOISE Results The proposal is to keep a conservative limit of 10kcps for PMTs integrated in DOMs. This value corresponds to the value in the plot of 8500cps (DOM glass contribution subtracted). This means that if all the 31 PMTs inside a DOM have a dark noise below 10kcps, only a fraction lower than 6% can be not-acceptable (that means <2 PMTs per DOM). D. Vivolo - DOM Integration Meeting 06/09/17

Proposal for NEW DOM Acceptance criteria Time over Threshold Current criteria: the current acceptance criterium for PMTs integrated in DOMs is 24ns < ToT < 30ns. This range was chosen in order to be “close” to the value of ToT (27.4ns) corresponding to the operational gain of 3x106. Preliminary: for all the 7000 tested PMTs an HV tuning has been mandatory in order to define the operational HV corresponding to a ToT of 27.4ns. The results of the tests on the sample of 7000 PMTs showed that, on average, the tuned values of HV are higher of 63.5V (in absolute value) with respect to the HV provided by the vendor. Analysis: for non-tested PMTs the reference operational value for the HV is HV_vendor-50. Reason: the HV-tuning is a step-process. It is centered on the HV vendor value and proceeds in steps of 25V (over and below the central value). Therefore statistics is available only for the HV_vendor-50V value. Consideration: such statistics can be considered fully indicative, provided the negligible difference of about 10V wrt the HV_tuned central value it has been taken as a reference the results of the first tests on all the 7000 PMTs (it means including red and yellow, obviously). It has been analyzed the fraction of PMTs having final ToT between 24ns and 30ns (current acceptance criterium) as a function of the values of the first ToT measured at HV_vendor-50. D. Vivolo - DOM Integration Meeting 06/09/17

Proposal for NEW DOM Acceptance criteria Time over Threshold Results The proposal is to set a new range for ToTs in the DOM acceptance tests between 23 and 32ns. In this range, PMTs have a probability of more than 90% to be ok. This means that less than the 10% of PMTs can be not-acceptable, corresponding to 3 PMTs per DOM. This is perfectly in line with the current acceptance criterium. Remark: even for PMTs having, at HV_vendor-50, an initial value of ToT between 24 and 30ns the probability of success is never 1. This is due to the fact that for some PMTs the HV tuning can fail, due to misbehavior of the PMTs. In this way, also this feature is taken into account. D. Vivolo - DOM Integration Meeting 06/09/17

Proposal for NEW DOM Acceptance criteria Time over Threshold Considerations: If we examine the current NCRs, we can see that ALL of them could be closed using this new criteria. And this is exactly what we expect based on our experience. Further proposal: how to address the cases of DOMs not passing the acceptance test for ToT we consider for each PMT the "failure" probability as from the plot and we make a sum on all the 31 PMTs: If the value is lower than 3 the DOM is accepted otherwise it is rejected This is to take into account that for most of the values in the new acceptance range the "success" probability is well above 90%. And of course this must be taken into account in case of problematic DOMs. If such proposal will be approved, this calculation can be integrated in the acceptance excel sheet and the calculation can be done automatically. This will automatically address the NCRs and automatically close many of them (or just avoid to open an NCR at all, with just a warning...) This will reduce the number of "effective" NCRs A similar approach can be defined also for what concerns dark noise. D. Vivolo - DOM Integration Meeting 06/09/17

to be updated DOM Integration Master document: APPLICABLE documents DOM Testing Current Version: 3 File Name: KM3NeT_DOM_2016_004-DOM_Testing_v3.docx Last Update: Nov. 2016 DCR: N/A List of changes: AHRS/Compass calibration and re-calibration New version: this part must be added to the existing file. Part to be added is already available: 80% KM3NeT_CALIB_2017_004-PRO_AHRS_Calibration_v3 DOM Integration plan Current Version: 5 File Name: KM3NeT_INT_2015_009-DOM_Integration_Plan_v5.docx Last Update: Nov. 2016 DCR: N/A List of changes: Planning for 2017 New version: a planning for 2017 has been recently proposed. If confirmed, updating the document is trivial. 90% D. Vivolo - DOM Integration Meeting 06/09/17

DOM Integration Master document D. Vivolo - DOM Integration Meeting What can be added What is still missing is documentation for non-standard procedures: - re-opening of DOMs - separating DOMs from the VEOC - re-closure of DOMs (external pressure gauge) - re-calibration of AHRS/Compass – done D. Vivolo - DOM Integration Meeting 06/09/17

D. Vivolo - DOM Integration Meeting New proposals DOM Integration software Integration of functional and acceptance test sheets inside the KM3NeT DOM Integration software (fill a window instead of an excel file). Advantages: data will be sent directly to the DB automatic log the excel file will be automatically produced (then it must be loaded on the elog) communication with the DB will be authomatized (no more python script) ONGOING check of CLB calibration details will be included automatic production of NCR, too! And automatic communication with the DB Database Integration of SRS inside the DB. This will help a lot with the documentation Every other idea is welcome! D. Vivolo - DOM Integration Meeting 06/09/17

D. Vivolo - DOM Integration Meeting Quality NCRs Discussion about NCRs is now possible, some items needed more investigation. Nikhef issues ToT for untested PMTs Dark noise for untested PMTs High rates in DOMs produced by some PMTs FPGA cooling pressure gauge during DOM re-closing clock reset some of these items are still under study New rules for documentation Shipment of DOMs requires some actions. A discussion has already been started. Agreement on possible actions Procedure must still be written ISRs will be adequately informed on new rules. D. Vivolo - DOM Integration Meeting 06/09/17

D. Vivolo - DOM Integration Meeting Miscellaneous Distribution of components Distribution will be arranged according to the plans for autumn DOM production. Discussion will be done after the reports from DOM integration sites Call for technicians A joint effort is now mandatory to finally solve the DOM closing issue. Drawing and cost estimate of the DOM closing table currently used in Amsterdam are available. We need to re-design the tool in order to have lower cost while keeping all the functionalities. Please ask your groups (or your local services) for volounteers. D. Vivolo - DOM Integration Meeting 06/09/17

D. Vivolo - DOM Integration Meeting Miscellaneous DOM Integration workshop Open a doodle, let’s start discussion. Guidelines about organization. 3 days for technicians (ISR must attend as well): Training on ALL the phases o DOM integration Done on a proper number of DOMs at different integration stages, in order to avoid waiting times 2 days for ISR’s only: safety rules, DOM testing, DOM integration software, quality…. The candidate site for the workshop is Nikhef. Naples is the only other possibility (also Ctania if it will pass the QA/QC inspection) The candidate period is October (after the CM). We should check compatibility with mass production stress tests. Discussion at SC for priority level (high, in my opinion) An accurate preparation phase will be needed. A call will be done Possibly, an additional training for “non-standard” operations should be considered Call for technicians A joint effort is now mandatory to finally solve the Dom closing issue. Drawing and cost estimate of the DOM closing table currently used in Amsterdam are available. We need to re-design the tool in order to have lower cost while keeping all the functionalities. Please ask your groups (or your local services) for volounteers. D. Vivolo - DOM Integration Meeting 06/09/17