SciFi. Forum on Tracking Detector Mechanics R. Walet. on behalf of the SciFi Tracker Group Rev_06

Transcription

1 SciFi Forum on Tracking Detector Mechanics 2015 R. Walet on behalf of the SciFi Tracker Group Rev_06 National Institute for Subatomic Physics Science Park 105, 1098XG Amsterdam The Netherlands

2 OVERVIEW 5 [m] R.Walet 2

3 SciFi Performance Summary Current tracking 2 sub-systems: Inner Track, Outer Tracker Outer Tracker 24 layers of 5 mm gas drift tubes (2.5m long straws) in 3 stations of X-U-V-X Resolution ~200 micron Inner Tracker silicon strip sensors with mm pitch 12x X-U-V-X stereo layers Resolution ~ 50 micron Upgrade tracking One single tracking Technology NEW SciFi Tracking Detector 12 fiber mat layers composed of scintillating fibers (2.5m, d=0,25mm) in 3 stations of X-U-V-X Resolution 80 µm Single hit efficiency: 96-97% Run trigger less (remove L0) at 40 MHz read-out (only software trigger) GOAL: Be able to run at higher luminosity R.Walet 3

4 Scintillating Fiber Tracker 2.5 m 250µm Fibres Fibre mats 2.5m 13cm Silicon PM (SiPM) array: µm Modules = Supporting panels + mats 3 * X-U-V-X Readout box w/ cooling (-40 o C) and FE boards 5m fibers mirrors 5m R.Walet 4 6 m

5 SUB-SYSTEMS; Infrastructure 5 [m] C-frames (12x) Modules (144x) Read-Out Box (288x) R.Walet 5

6 Challenges Replace Inner and Outer tracker with a single technology Higher granularity to reduce occupancy Reduced material, Light weight High rate capability Large scale detector with fine measurement, handle deformations of the fibers (modules) and read-out To mitigate radiation damage until collecting at least 50 fb -1, SiPMs need to be cooled down to -40 C Relative alignment SiPMs and fibers Modular design with easy maintenance or replacement procedures High Resolution 5 meter C-Frame with module R.Walet 6

7 Modules (144x) Very schematically a Module is: 1,5 mm 1. A core of scintillating fibers, combined in a mat (8 mats and a mirror makes one core) 2. Sandwich construction Module Endpiece 0.52 meter CHALLENGES Winding of the fibermats Polishing of the optical surfaces Flat/straightness assembled modules Materials Description Material kg/module TOTAL Scintillating fibers 94% polystyrene + 6% PMMA Honeycomb cores Nomex Casting and winding epoxy Epotek Panel assembly glue Araldite Carbon fibre skin Phenolic Resin 1,5 216 Endplugs* Aluminum 9, R.Walet TOTAL

8 Modules Fibermats Cutting slit Winding wheel Casting glue ; - protection layer 150μm - 1 day gluing - 3 days curing 2.5 meter Fibermat winding machine 13cm Alignment holes for module assembly Casted Fibermat Fibermat casting JIG R.Walet 8

9 Modules Sandwich R.Walet 9

10 SiPMs(4608x) Silicon Photomultipliers (SiPM) 60μm pixel mm 128 channel array 1.62 mm Kapton flex-pcb Particle track 6 layers of fibre per plane (Fiber D=0.250mm) Connectors mm R.Walet 10

11 Read-out Box (288x) Very schematically a ROB is: 1. SiPMs, SiPM cables, SiPM cooling, etc. COLDBOX 2. FE electronics boards, cables, etc. FE ELECTRONICS Cabling, piping CHALLENGES thermal expansion and contraction (different CTE s with T of C) high position accuracy s condensation and frost prevention R.Walet 11

12 Read-out Box Thermal Design ISSUE 1. Different CTE s Material CTE T L [µm/sipm* ] [ppm/ C ] [-50 Cv 40 C] (*=32,59 mm)] Silicium 2,6 7,6 Ti6Al4V 9 26,3 Copper 16,6 48,6 90 SS316 16,2 47,4 Epoxy ,6-190,1 Polycarbonate ,8 ISSUE 2. Behavior of the Endpieces by cooling down (every photon counts!!!!) Top: -40 C 13cm Overall deformation 0.2 mm Outer: 5[W/mk], 16 C Y=0.1mm; Airgap SiPM-Fibers X±0.2mm; mis Alignement SiPM-Fibers 0mm R.Walet 12

13 Read-out Box Cooling bar R.Walet 13

14 Concept 1. Read-out Box Cooling bar R.Walet 14

15 Read-out Box Cooling bar Concept 2. Y fixed Spring force; optimal optical contacts Z fixed 4-SiPMs heat spreader with SiPM cooling block (copper) X fixed Z fixed 3 positioning pins in end piece 3D printed bellows 4-SiPMs heat spreader with SiPM cooling block (Ti6Al4V) R.Walet 15

16 Read-out Box Cooling bar Concept 3. (new input; parallel cooling with d=2mm possible) Y fixed Z fixed X fixed Y fixed Z fixed EACH INDIVIDUAL COOLING SUBSTRATES POSITIONED AND ALIGNED WITH RESPECT TO SINGLE FIBER MAT R.Walet 16

17 Concept 4. Read-out Box Cooling bar Section; cooling bar EACH INDIVIDUAL COOLING SUBSTRATES POSITIONED AND ALIGNED WITH RESPECT TO SINGLE FIBER MAT Y fixed Y fixed Y fixed Z fixed X fixed 3D printed Ti-alloy Grade 5 (min. Wall thickness 0,25mm) Bellows (SS) from Witzenmann Challenge to braze SS (bellows) on Ti (bar) Alternative: investigate 3D-printing of full cooling bar (incl. flexible joints) Z fixed R.Walet 17

18 Concept 5. Read-out Box Cooling bar Alternatives; 1. Copper pipe d=2mm 2. Pre-formed corrugated SS pipe D=3.5 d=3.3 mm R.Walet 18

19 Read-out Box Enclosure FE electronics In-/outlet pipe cooling Top cover with SiPMs, SiPM cables, SiPM cooling Thermal enclousure (insulation box) Optical surface fiber ends Module with interfaces R.Walet 19

20 Read-out Box Enclosure Requirements Coldbox to Module connection: o Flat sealing surface around module o Air tightness of all components within this surface o Mounting holes 2x7 m3 Contacted companies, 3D printing; o Shapeways o 3D systems o Heijcon Coolingbar -40[degC] SiPM package R.Walet 20

21 Read-out Box Enclosure Soft Glue silicon G10 stiffner Mounting holes Bends to increase flexibility to compensate for thermal shrink and release forces on the connectors R.Walet 21

22 Read-out Box Enclosure Outer shells are 3D printed in PA2200(Wall thickness 0,7mm) Parts will be filled with insulation foam Cold box PU foam R.Walet 22

23 Read-out Box Enclosure First cold-boxes filled (without using molds) Good experience; but some air gaps in cold box. In parallel, order more boxes with: Different materials (e.g. ABS) Different printing orientation (improve flatness) R.Walet 23

24 1/8 VCR inside, ½ VCR outside Open vacuum pipe to Manifold Vacuum insulation Vacuum feedthrough Standard bellows Feedthrough topcover End vacuum insulation R.Walet 24

25 Vacuum feedthrough Vacuum insulated pipe Feedthrough reducer 1/8 VCR inside ½ VCR outside Open vacuum pipe to Manifold Vacuum pipe crosses SiPM cables Oversized bellow to be able to open 1/8 VCR End vacuum insulation R.Walet 25

26 Vacuum feedthrough Press to access 1/8 connector 1/8 VCR inside ½ VCR outside Open vacuum pipe to Manifold Oversized bellow to be able to open 1/8 VCR Mounting position Opening position R.Walet 26

27 Conclusion & Outlook the SciFi tracker is an essential component of the upgraded LHCb detector it will allow running at (5 ) higher luminosity an extensive irradiation program demonstrated radiation tolerance of main components we can handle damage to fibres (6 layer mats) and SiPMs (cooling down to 40 C) lots of progress in new technologies fiber winding and fiber-mats production on massive scale custom design of SiPM arrays matching fiber geometry direct fiber-to-sipm interface SiPM cooling down to -40 C in small volumes, modular approach (Read-out Boxes) High functionality level per volume extensive use of exotic technologies like 3D printing large collaboration between 17 institutes* from 8 countries series production to start in 2016 installation in 2019 during LHC shutdown *17 institutions: Kurchatov, ITEP, INR (RUS), Aachen, Dortmund, Heidelberg, Rostock (GER), EPFL (SUI), ClermontFerrand, LAL, LPNHE (FRA), Nikhef (NL), Barcelona, Valencia (SPA), CBPF (BRA), Tsinghua (CN), CERN R.Walet 27

28 Back-up slides R.Walet 28

29 Take e.g. Laird 6200 T-flex Thermal Gap Fillers For A SiPM ~ 2 cm 2 and P SiPM ~ 2 W, T(100 kpa) = 13 C and T(500 kpa) = 4.5 C For A SiPM ~ 2 cm 2, 100 kpa 20 N/SiPM force! R.Walet 29

30 Radiation Damage - Fibers Light transmission of scintillating fibre decreases under irradiation up to 35 kgy expected near the beam pipe over the upgrade lifetime A mix of low dose, low rate xray, gamma, and high rate, high dose proton irradiations Expected ionizing dose for LHCb Upgrade As measured by PIN diode Expect a 40% loss of transmitted light created near the beam pipe after 10 years R.Walet 30

31 Radiation Damage - SiPM We expect 1.3 x neq/cm 2 for 50 fb -1 Requires cooling to -40 C 150m of silicon arrays, without vacuum DCR of a few MHz per channel at -40 C after 50fb -1 ~1 per 5-10 bunch crossings SiPM arrays SiPM arrays DCR reduction: factor 2 every t=-10 o C Plot from N. Lopez March and M.Karacson Image from D. Gerick, presented at DPG Wuppertal, R.Walet 31