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Diamond Manufacturers for ATLAS Upgrades. Brief Overview: Next Upgrade (IBL): Diamond Beam Monitor (DBM) News from two diamond manufacturers E6/DDL II-VI News from diamond cutting & thinning companies Summary. Diamond Beam Monitor. BCM. DBM: 3.2< η <3.5.
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Diamond Manufacturersfor ATLAS Upgrades Brief Overview: Next Upgrade (IBL): Diamond Beam Monitor (DBM) News from two diamond manufacturers E6/DDL II-VI News from diamond cutting & thinning companies Summary R. Kass
Diamond Beam Monitor BCM DBM: 3.2<η<3.5 R. Kass Part of IBL upgrade • Bunch-by-bunch luminosity monitor (aim < 1 % per BC per LB) • Finer segmentation & larger acceptance than BCM • Never saturates • Internal stability monitoring • Bunch-by-bunch beam spot monitor • Need triple-module telescopes for (limited) tracking • Can distinguish hits from beam halo tracks • Unbiased sample, acceptance extends far along beam axis • Baseline: 4 telescopes of 3 IBL modules per side → 24 total diamonds • Avoid IBL insertion volume and ID acceptance (η>2.5) • Place in pixel support structure close to detector and beam pipe
DBM Diamond Sensor Plan Diamond Sensors for DBM: type: polycrystalline CVD diamond size: 21 x 18 mm2, 525 ± 25 mm thickness number: 40-45 need for DBM modules 24 + spares 5 for Irradiation studies 21 x 18 mm2 pCVD diamond Some parts already in hand that need cutting and/or thinning Two diamond suppliers involved: DDL/E6 (UK based) II-VI (US based) R. Kass
Sensors from DDL Ten Detectors ordered from DDL/E6 (thick E6 wafer – Wafer 9) • Plan was for wafer to be tested at OSU → wafer characterization → device selection • Wafer 9 received from E6 11-Jan-2012 • Rind still attached • Defect level looks ok • Wafer 9 returned to E6 - rind removal • Wafer arrived at OSU, test grid applied, being testing R. Kass
Wafer 9 from DDL Growth side Substrate side 5 inches R. Kass
Thickness of wafer 9 from DDL As grown thickness varies from ~1.24 to 1.48 mm R. Kass
Collection Distance & Current Characterisation of DDL’s wafer 9 CCD (mm) current (nA) Good regions have I <5 nA at 1000V in air All regions of wafer 9 look good We are almost finished measuring the CCD & I in all regions of the wafer Expect to finish measuring the CCD & ship back to DDL/E6 mid-week R. Kass
Electric Field Characterisation of DDL’s wafer 9 Need to take into account the varying thickness of the wafer Scale previous CCD plot to E=0.66V/mm This information allows us to make a “cut map” R. Kass
Cut Map Example Based on the CCD and thickness info we divide the wafer into “sensors” wafer 8 Wafer 8 was cut into eleven 2 x 2 cm2 sensors R. Kass
E6/DDL Production Capabilities Get 10-15 FE-I4 sensors per wafer Ordered 10 DBM Sensors detectors from DDL’s wafer 9 21 x 18 mm2 with CCD>200 mm at 1000V Each piece will be thinned to 525 mm Expect the pieces to arrive in June Processing takes 6-10 weeks after return of wafer Expect to have access to 10-20 wafers/year determined by the orders we place R. Kass
Work with II-VI II-VI is the “2nd Company” www.ii-vi.com 5 inches II-VI makes “optical grade” cvd diamond laser windows.. Wafer Results • Can grow thick wafers - 2 mm thick • grown for another application • Very good CCD results • 300 µm @ 0.5 V/µm • Problems with N2 and growth rate • problems showed up at the edges R. Kass 11
Sensors from II-VI • Proceeding to develop additional supplier of detector grade material based on their samples • Good CCD results • 300 µm @ 0.5 V/µm even though grown for another application and problems with N2 • Modified growth process • ATLAS committed to produce one detector grade wafer by June with option for second wafer • Quote received 9-Feb: • specified ccd >250 µm @500µm thickness • ATLAS placed order for 10 parts with option for 10 more R. Kass
Cutting & Thinning Parts in Hand Have tested part thinning (750μm→525μm) • 1cm x 1cm part used, came back fine Sent first 2cm x 2cm parts for thinning returned with edge problems we are looking into a laser trimming repair looks do-able Sent: one 2x6 for cutting & thinning four 2x2’s for thinning Expect three weeks to get 2x2 parts back If ok → send remainder of parts R. Kass
Summary Two manufacturers are in place: DDL, II-VI Three orders of sensors from two manufacturers: DDL: 11 (wafer 8) + 10 (wafer 9) wafer 9 being tested II-VI 10 (with an option of another 10) looking forward to receiving their pieces in May CCD measurements on DDL’s wafer 9 just about finished will ship back to DDL/E6 shortly Progress on wafer thinning working with 2 companies in the US Can now get 100’s of sensors/yr R. Kass
Extra Slides R. Kass
Introduction: Diamond as sensor material Radiation Studies Single-crystal CVD & poly CVD fall along the same damage curve Proton damage well understood At all energies diamond is >3x more radiation tolerant than silicon
Radiation Damage - Basics • Charge trapping the only relevant radiation damage effect • NIEL scaling questionable a priori • Egap in diamond 5 times larger than in Si • Many processes freeze out • Typical emission times order of months • Like Si at 300/5 = 60 K – Boltzmann factor • A rich source of effects and (experimental) surprises ! 17 R. Kass: DOE Review