Study of Study of dama damages ges induce induced d on on A ATLAS sili TLAS silico con by f n by fast ast extr xtract acted ed and and inten intense se pr prot oton on be beam am ir irrad adia iation tion C. Bertella, C. Escobar, J. Fernández, C. Fleta, A. Gaudiello, G. Gariano, C. Gemme, S. Katunin, A. Lapertosa, M. Miñano Moya, A. Rovani, E. Ruscino, A. Sbrizzi, M. Ullán PIXEL 2018, Taipei, 10-14 December 2018
Introduction ➢ The ATLAS silicon tracker detectors (Pixels, Strips) are designed to sustain high dose integrated over several years of operations at the LHC ➢ The radiation hardness should also favor the survival in case of accidental beam losses ➢ ATLAS Pixel modules are able to survive to LHC beam loss scenarios [ NIM A565 (2006) 50-54 ] ➢ LHC will be upgraded to higher luminosity (HL-LHC) ➢ To cope with HL-LHC conditions, ATLAS is planning a complete update of the tracker: ➢ The new inner tracker (ITk) will replace the current tracking system ➢ ITk will be an all silicon tracker system ( ITk Strip TDR, ITk Pixel TDR) ➢ The damage threshold needs to be measured for the new ITk Pixel and Strip modules ➢ The new damage threshold needs to be compared with beam-loss scenarios in HL-LHC ➢ The comparison will be useful as feedback for the choice of the HL-LHC collimator material ➢ The goal of this study: ➢ Study the effects of accidental beam-loss scenarios for ATLAS Pixels and Strips at HL-LHC: ➢ Provide a realistic estimate of the damage threshold for sensors and electronics ➢ Evaluate the performance degradation due to the radiation damage 10-14 December 2018 A. Lapertosa 2
HL-LHC conditions ➢ HL-LHC beam loss scenarios: ➢ Asynchronous beam dump ➢ Wrong injection settings ➢ Beam injection and shielding at HL-LHC: ➢ New triplets injection magnets ➢ Larger TAS aperture (from 17 to 30 mm radius) ITk layout example (not final layout) TAS is a 1.9 m long copper cylinder inside the ATLAS shielding system R = [17 mm, 250 mm], Z = 19.04 m After 4000 fb -1 Pixel layers: up to 10 16 1 MeV n eq / cm 2 fluence Strip layers: up to 10 15 1 MeV n eq / cm 2 fluence TAS ITk Pixel TDR 10-14 December 2018 A. Lapertosa 3
HiRadMat facility ➢ Test beams performed at the HiRadMat facility: ➢ Facility at CERN providing high-intensity pulsed beam Beam parameters ➢ 440 GeV proton beam extracted from CERN SPS ➢ Two separated tunnels: ➢ TNC: beam line with experimental tables ➢ TT61: powering/read-out system ➢ Experimental setup: ➢ Long cables passing through a concrete wall ➢ Cables connect powering and read-out to devices ➢ Operation on the modules must be remotely controlled Powering and read-out TNC TT61 10-14 December 2018 A. Lapertosa 4
2017 and 2018 test beams ➢ Test beams performed at the HiRadMat facility: ➢ 440 GeV proton beam perpendicular to silicon modules ➢ Two irradiation schemes: Global (2 mm radius) and Local (0.5 mm) ➢ Increasing the number of bunches step-by-step ➢ From 1 to 288 bunches ➢ 25 ns spacing between bunches ➢ Up to 1 · 10 11 protons per bunch ➢ Experimental setup aligned with the beam ➢ Modules mounted on frames ➢ Frames loaded in experimental box ➢ Box placed on aluminum table in the tunnel Year Beam radius Goal Bunches (1, 4, 12, 24, 36, 72, 144, 288) x 5·10 10 p, 288 x 10 11 p 2017 2 mm Global irradiation (1, 12, 72, 288) x 10 11 p 2017 0.5 mm Local irradiation (1, 12, 24, 36, 72, 144, 288, 288, 288) x 10 11 p 2018 2 mm Global irradiation (1, 12) x 10 11 p 2018 0.5 mm Local irradiation 10-14 December 2018 A. Lapertosa 5
Experimental box (2017 and 2018) ➢ Design and construction of the test-box: ➢ Material: epoxy fiber glass, makrolon and aluminum ➢ Designed to host a maximum of 8 detector modules mounted on dedicated frames 10-14 December 2018 A. Lapertosa 6
July 2017 test beam ➢ 2017: ➢ 2 IBL Pixel modules (3D sensor + FE-I4) ➢ 1 ITk Strip DAQload (ATLAS12 + ABC130) ➢ Issues with operations: ➢ Not able to fully read-out Strip sensor ➢ Cooling fans not properly working ➢ Temperature drift: from 30 to 60 °C Module IBL Pixel ITk Strip 2x2 cm 2 1x1 cm 2 Module size Chip FE-I4 ABC130 Sensor type 3D ATLAS12 Sensor thickness 230 μ m 320 μ m Channels 26680 104 (pitch) (50x250 μ m) (74.5 μ m) Max design dose 250 Mrad 35 Mrad 10-14 December 2018 A. Lapertosa 7
Experimental box: 2018 improvements ➢ Design and construction of the test-box: ➢ Material: epoxy fiber glass, makrolon and aluminum ➢ Designed to host a maximum of 8 detector modules mounted on dedicated frames ➢ Improvements in 2018 setup: ➢ Darkening of the box (aluminum tape) ➢ Cooling system working: 4 fans (12x12 cm) with filters ➢ Air flux controlled remotely ➢ Motor system to move box in/out of the beam 10-14 December 2018 A. Lapertosa 8
May 2018 test beam ➢ 2018: ➢ 1 IBL Pixel module (Planar sensor + FE-I4) ➢ 2 ITk Strip DAQloads (barrel mini petalet / LowR + ABC130) ➢ Improvements on modules: ➢ Fully read-out of one ITk strip module (LowR) ➢ Heat dissipation in Pixel frame (heat sinks) ➢ Stable temperature at 36° C Module IBL Pixel ITk Strip 2x4 cm 2 0.7x2.6 cm 2 Module size Chip FE-I4 ABC130 Sensor type Planar LowR Sensor thickness 200 μ m 310 μ m Channels 2x26680 64 (pitch) (50x250 μ m) (77 μ m) Max design dose 250 Mrad 35 Mrad 10-14 December 2018 A. Lapertosa 9
2017 setup with 3D Single chip IBL Pixel Module 10-14 December 2018 A. Lapertosa 10
Pixel measurements (2017) Module 1 - IBL 3D Module 2 - IBL 3D Two different Stable beam: Stand-by: configurations during Sensor bias On Sensor bias Off the beam transit FrontEnd pre-amplifiers On FrontEnd pre-amplifiers Off Noise 2D map extracted from threshold scan (HV On: -20 V) Leakage current increase after irradiation (normalized to 273 K) Reference: before test After 2 mm beam (1-288 b) After 1 week of parasitic irradiation (beam to RotColl) 10-14 December 2018 A. Lapertosa 11
Pixel measurements (2017) ➢ Global irradiation: 2 mm radius beam 17 July 2018 ➢ Both modules survived to 288 bunches ➢ Self-triggering scan after beam transit ➢ Beam spot visible due to material activation ➢ Intensity of the spot increasing after each shot ➢ Intensity of the spot decreasing with time ➢ Low residual activity after 1 week After glow ➢ Local irradiation: 0.5 mm radius beam (288 b, 2 mm) ➢ Readout chip LV in short after 288 bunches ➢ Small bump visible on flexible PCB Small bump on 25 July 2018 flexible PCB After glow 2.8 mm (72 b, 0.5 mm) Low residual activity after one week 4.3 mm 10-14 December 2018 A. Lapertosa 12
2018 setup: IBL DC + metallic contact & heat sinks 10-14 December 2018 A. Lapertosa 13
Pixel measurements (2018) ➢ Module tested in Stable beam configuration Default ➢ Monitoring of leakage current after each shot 1 b ➢ Each bunch is made of 10 11 p 4 b 12 b ➢ Before irradiation: 2 μA at -80 V 24 b ➢ Increase after irradiation: 170 μA at -80 V 36 b 72 b ➢ Bulk and surface damage post-irradiation 144 b ➢ Linear increase of the leakage current 288 b ➢ agree with expectations (Hamburg model) Linear fit Linear fit . . . Bias: -80 V Temperature: 36 °C 10-14 December 2018 A. Lapertosa 14
Pixel measurements (2018) Noise from threshold scan: Beam simulation: ➢ Correlation between after 288 bunches after 288 bunches performance degradation and proton fluence 120 e - ➢ Noise increase per pixel used as figure of merit 250 e - ➢ Proton beam simulated taking into account beam position and bunches ➢ Estimated fluence at Noise vs Flux beam center: 14·10 9 p correlation ➢ Noise starts to increase after 4 bunches ➢ Constantly increases after each pulse 10-14 December 2018 A. Lapertosa 15
2018 setup: ITk Strip (LowR + ABC130) 10-14 December 2018 A. Lapertosa 16
Strips measurements (2017/2018) ➢ Leakage current continuosly recorded ➢ Peaks right after the beam transit ➢ About 10 minutes relax time Preliminary ➢ Constant increase with radiation ➢ Increment is approximately linear 2017 Bias: -6 V 2018 Bias: -150 V 10-14 December 2018 A. Lapertosa 17
Strip measurements (2018) ➢ 64 channels ➢ Gradual loss of channels ➢ 50% channels lost after 36 bunches Beam 2 mm radius 36 bunches Before test 4 bunches 24 bunches 288 bunches ➢ Noise before and after shots ➢ Many noisy/damaged channels in region interested by the beam ➢ Mainly around the beam center 10-14 December 2018 A. Lapertosa 18
Strip measurements (2018) Fraction of noisy/good/damaged strips close by or far from the beam 10-14 December 2018 A. Lapertosa 19
IBL Pixel results @ HiRadMat ➢ Three IBL modules were tested with different configurations with SPS beam @ HiRadMat ➢ Two configurations used to reproduce ATLAS operations: “stand - by” and “stable beam” ➢ Two different IBL structure tested: 3D and Planar ➢ Noise increases around the beam spot in a similar way for the three modules ➢ In 2017, we proved that IBL 3D modules are able to sustain 288 bunches with 2 mm radius ➢ In 2018, we proved the same with IBL Planar module ➢ This time, we shoot 3 times 288 bunches → the module survived ➢ We are confident that IBL modules are able to sustain such an intense energy release ➢ We set a conservative damage threshold limit on IBL modules: 10 13 p/cm 2 ➢ Estimated taking into account 288 bunches made by 10 11 protons on 2x2 cm 2 surface 10-14 December 2018 A. Lapertosa 20
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