QA, QC, Test plan F. Pietropaolo CERN / INFN Padova
Quality Assurance / Quality control • The Quality Assurance (QA) plan is as set of acAviAes for ensuring quality in the process by which products are fabricated and assembled. The quality is determined by how well the final product meets the defined requirements. The QA plan aims to prevent defects proacAvely by prototyping, tesAng, and documenAng the process. The QA plan is designed to miAgate the Risks and Hazards. • Quality Control (QC) is a set of acAviAes for ensuring quality in product. The acAviAes focus on idenAfying defects in the actual products produced. • The first step for insuring that the detector meets requirements is the creaAon of an integrated model of the enAre TPC to evaluate interfaces and installaAon methods. This integrated model will facilitate the development of installaAon plans and insure that all components fit together as expected. Link to … !!!. 2
Planned QA Program • Incorporate lessons learned into design Perform comprehensive stress analysis from component level to full detector • structure 2D and 3D electrostaAc studies of the electric field in the high field regions of • the TPC • Transient analysis of CPA, FC electrical behavior in a HV discharge Material test • – ResisAve material electrical tests – Electrode material test • FC end cap tests • Fiberglass material mechanical/thermal tests • Small scale full E field FC test in 50l • Full voltage HV test in 35ton cryostat • Divider component and assembly thermal and electrical tests • Ash River full scale mockup assembly 3
QA: ResisAve panels R&D InvesAgated materials: NORPLEX, Micarta, NP 315, phenolic laminate (“bakelite”) with graphite, • – Intrinsic bulk resisAvity in the required range (few MOhm/cm) – Density comparable to LAr FR4 glass/epoxy coated with resisAve layers: • – resisAve ink (~100kOhm/square) printed with specific pa`erns; – laminated resisAve kapton foil Dupont 100XC10E7 (25 µm thickness, graphite loaded, available with resisAvity in the 0.5 to 50 MOhm/square range available in 1.2 m wide rolls) • Preferred choice: due to lower radioacAvity, more uniform resisAvity, be`er aging to sparks, high stability in LAr (~50% increase in resiAvity, no planarity deformaAon) Also considered: • – Graphite loaded (outer layers) FR4 – Thin films of Germanium Coated Polyimide (vacuum deposited) 4
LaminaAon of resisAve Kapton foils on FR4 Standard PCB technique applied at CERN to develop • resisAve thick-GEM’s (max 0.6x0.7 mq) – Stack of FR4 panel + 75 um prepreg + 25 um Kapton foil placed in between metallic sheets and unmoulding foils – Press cycle at 20 Kg/cm2 for about 1 hour at 160-200°C – Press available (Italy, Japan) for dimensions amply larger that 1.2 m x 2.4 m – LaminaAon on both sides of FR4 also possible Several samples produced at CERN with size up to 0.6 • x 0.7 mq ( 3mm FR4 thickness) Measurement of resisAvity uniformity (2-3 MOhm/ • square in present sample) Long term immersions in LAr (weeks) with several • thermal cycle from room to LAr temperatures to check stability against delaminaAon performed posiAvely. No planarity deformaAon in LAr observed • 5
Prototypes for Lar-TPC’s Two 35x35 cm2 panels fabricated and • machines as cathode plane for the 50-liter LAr-TPC available at CERN. – already operated several Ames in various test runs, with behavior completely equivalent to that of the metallic planes in term of mechanical stability, electric field uniformity and LAr purity. MDT produced a full size 1.2 m x 2.1 m • prototype panel (double sided) following the CERN fabricaAon procedure. – machined by them into smaller elements to be installed in the 35 ton HV test at FNAL. The resisAve strip, required for be`er electric • field uniformity around the CPA frame will – Being these elements much smaller with respect to the CPA panels and requiring in addiAon more precise machining and hole drilling, they could be fabricated at CERN. – A first set has been already produced for the 35 ton HV test at FNAL. 6
QA: Mini-field cage tests To validate the field cage concept in pure LAr • Designed to fit in the ICARUS 50 liter cryostat (60 cm diameter, • 1.1 m height; ~300 liters total volume) Roll-formed metal profiles with UHMW PE caps • – Choice of metal (Al, SS) and surface finish Pultruded fiberglass I-beams form 4 mini panels • All profiles are at same potenAal to simplify HV connecAon • Perforated ground planes 66mm away: 1/3 of FD • bias voltage required: to reach design E field ~ 60 kV are needed Corona-discharge monitor on Power supply cable • (based ICARUS scheme) Video camera to visually detects light flashes for • from arching/discharges and monitor LAr thermal stability (LED illuminated) High HV stability in pure LAr up to 80 kV/cm and • up the 100 KV if thermally stable (no bubbles) No difference on material choice (AL, SS), surface • finish (roll formed vs extruded) surface quality (up to 100 um scratches) 7
R&D on aluminum field cage Malter effect in Liquid Argon? • Test effects of possible charge-up due to • oxidaAon on uncoated aluminum surface of FC: – A new field cage of 50 liter LAr-TPC has been built. – 50 rings made of uncoated extruded 10x10 mm2 aluminum bars with rounded outer corners (4 mm radius) – Spaced by 10 mm – Coupled with resisAve cathode – Minimum distance of rings from detector vessel wall: 5cm – Max local e-field at ring surface ~ 26 kV/cm (for Vcath=-25 kV, 500 V/cm driu field) similar to ProtoDUNE SP case Under test by beginning of November to • Long term operaAon (several weeks) verify HV stability, electronic noise on maybe required to measure charging wires, possible producAon of UV light up effects due to cosmic rays 8
Extruded aluminum profiles for FC ProducAon: • – OpAmizaAon of sAffened aluminum extruded profiles; mechanical properAes verified (with FEA calculaAon) at CERN. – Same outer shape as roll formed profiles, compaAble with standard locking nuts and tooling for mounAng – ProducAon of prototypes started at selected producers (ALEXIA-Italy, MIFA-Netherland) with different aluminum alloy and with conducAve coaAng (at some cost increase). – Prototypes (1.5 m long) verified at CERN. – First 100 m available on 11/15 th (sufficient for second phase of the 35 ton HV test): 50m with conducAve coaAng (SURTEC). – Full producAon (~3km) for ProtoDune SP available in few weeks Ame – Cost ~ 1 to 2 Euro/m Full compaAbility between SS roll formed • and extruded aluminum profiles; final choice can be made at very last moment 9
QA: Mechanical mock-up in Ash River, MN • Full scale ProtoDUNE-SP components (FC, CPA, support structures) • Tests of interfaces and handling • Test of assembly procedures Presently underway 10
Ash River InstallaAon components One APA frame (no wires) • 4 CPA columns (without resisAve laminaAon) • – FR4 Frames completed with FR4 panels 4 Top/Bo`om FC Panels: • – 2 Panels with latest design (No splice joint and latest modificaAons) – 2 panels older version with stainless hardware just for mockup. 4 End-wall Panels: • – Top panel with hangers – Panel with beam plug mockup. – 2 Regular End wall panels. Most panels fully populated with field shaping profiles • Few end caps missing. • AddiAonal weight on the panels to make up for missing weight due to • missing ground planes (replaced by plywood) . 11
Ash River present Achievements Phase 1 of the ProtoDUNE Trial Assembly Hanging the first CPA • Geyng elevaAons in TPC correct • Moving the first CPA Pair • Hanging the first Field Cage • RotaAng the FC • Packaging for shipping • 12
QA Plan: HV • HV feed-through – Follow/contribute to ConstrucAon and tests in collaboraAon with the DP ETH/CERN group. • Perform HV test at 35-ton, including the following: – Tested ability to hold voltage at full scale; – Tested expected current and stability of current at all monitoring points; – Tested mechanical integrity of all components auer full cool-down, warm-up cycle; – Tested discharge miAgaAon system using induced HV discharge. 13
Proto-DUNE SP FC-CPA-HV Test at FNAL PC4 • Overview & InvesAgaAons • EvaluaAon of the design of ProtoDUNE from a high voltage perspecAve • Design verificaAon • Expose any design weaknesses. • What voltage can be held • MoAvaAons • High voltage issues in liquid argon are not completely understood • A breakdown will likely set the operaAng voltage of the experiment • Breakdown can damage the detector • Test will be performed in ultra-pure LAr in the membrane cryostat of the 35 t facility 14
The field cage for the HV test • The full-sized ProtoDUNE TPC components do not fit in the cryostat • However, the test will be a full-field test . • The device will have the first 10 profiles of the FC and a resisAve cathode at their planned 1.5m voltages. Individual components: • – High field areas à corners near cathode – New aspects of the design: FC profiles and FRP beams, resisAve plate cathode, ground planes, 1.5m – However: dedicated HV feed through (UCLA) From B. Yu And the integraAon of the pieces • – Do the pieces of the design work together? Cathode Resistor to ground Poten:al (kV) Rela:ve 15 Anode
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