August 99 E.Auffray CMS/ECAL STATUS on PWO crystals from Bogoroditsk after one year of preproduction for CMS-ECAL Etiennette Auffray SCINT 99, 16 August 1999

August 99 E.Auffray CMS/ECAL Importance of R&D effort 95 98

August 99 E.Auffray CMS/ECAL Since the 4th September 98, we received : 1000 preproduction crystals from BTCP: 100 : 04/09/ : 03/11/ : 08/12/ : 22/03/ : 22/06/99 All have been visually Inspected All have been characterised with ACCOS (Automatic machine to measure : 3D, transmission, decay time,LY ) Some have been irradiated 61 irradiated in High dose rate (500Gy, 240Gy/h) 129 irradiated in Low dose rate (3Gy, 0.15Gy/h) 400 used for the 1st module of CMS/ECAL in CERN/lab27 regional center First crystals La doped & progressively changed to Y-Nb doped

August 99 E.Auffray CMS/ECAL Reception of first 100 preproduction crystals

August 99 E.Auffray CMS/ECAL Quality check of first 1000 preproduction crystals

August 99 E.Auffray CMS/ECAL Optical Specifications for Preproduction  Longitudinal transmission  10% at 350nm  55 % at 420nm  65 % at 600nm  Transversal transmission –For T=50%   6nm  S >1.5 %/nm between 340 and 370nm  For “blue” crystals : LY in labo27 at 8X o  8 pe/MeV 2 pe/MeV with 1 EG&G APD (BT97)  Decay time LY(100ns)/LY(1  s) > 90% No visible afterglow »< 0.5% background with 1MBq source in standart decay time measurement Good radiation Hardness

August 99 E.Auffray CMS/ECAL Bogoroditsk Preproduction Status 16 August, 99  1500 crystals delivered Mid of August

August 99 E.Auffray CMS/ECAL Dimensions AR-Nominal value Batch 1 19/100 rejected 19% On all dimensions Batch 2 14/100 rejected 14% Batch 2 19/200 rejected 8.5% -100  00

August 99 E.Auffray CMS/ECAL Dimensions AR-Nominal value Batch 4 8/200 rejected 4% On all dimensions Batch 5 9/400 rejected 2.25 % -100  00

August 99 E.Auffray CMS/ECAL 420nm Optical Transmission Distribution for 1000 crystals 3.2% below 55%

August 99 E.Auffray CMS/ECAL 420nm Optical Transmission Batch 1 11/100 rejected 11% Batch 2 6/100 rejected 6% Batch 3 15/200 rejected 7.5%

August 99 E.Auffray CMS/ECAL 420nm Optical Transmission Batch 4 0/200 rejected 0% Batch 5 0/400 rejected 0%

August 99 E.Auffray CMS/ECAL Light Yield Distribution for 1000 crystals LY at 8X o 2.2% below 8pe/MeV

August 99 E.Auffray CMS/ECAL Light Yield 0/100 rejected 0% 0/100 rejected 0% 1/200 rejected 0.5% Batch 3 Batch 2 Batch 1

August 99 E.Auffray CMS/ECAL Decay time Distribution for 1000 crystals % of emitted light in 100ns

August 99 E.Auffray CMS/ECAL The slope of longitudinal transmission between 340nm & 370nm

August 99 E.Auffray CMS/ECAL The slope of longitudinal transmission between 340nm & 370nm 0.1% below 1.5%

August 99 E.Auffray CMS/ECAL Radiation damage certification of Russian crystals  Irradiation of ingot’s top and bottom parts –All crystals –At Bogoroditsk –To control radiation hardness uniformity  High dose & dose rate side irradiation (induced absorption at all ) –Sampling (20%) –At Bogoroditsk after March 99 –To control absolute radiation hardness and uniformity  Transverse transmission along the crystal –All crystals –At Bogoroditsk and at CERN –To control doping uniformity  Longitudinal transmission band edge slope –All crystals –At Bogoroditsk and at CERN –To predict radiation hardness  High dose & dose rate side irradiation (induced absorption at all ) –Sampling (20%) –At Geneva hospital (CERN) – To control absolute radiation hardness & uniformity  Low dose rate front irradiation (LY loss) –Sampling (20%) –At CERN (TIS) –To control radiation hardness in LHC conditions  Low dose rate side irradiation (transmission loss at ≠ ) –Sampling (20%) –At CERN (X5) –To control radiation hardness uniformity

August 99 E.Auffray CMS/ECAL Sampling irradiation tests Batch 3 & 4 Front irradiation 0.15Gy/h

August 99 E.Auffray CMS/ECAL Radiation Hardness Lateral irrad., 500Gy, 240Gy/h Front irrad., 1.5Gy, 0.15Gy/h

August 99 E.Auffray CMS/ECAL Status of crystal delivery from Bogoroditsk (Russia) crystals delivered 28 May 1999

August 99 E.Auffray CMS/ECAL Conclusion Ramping up in production rate according to plans Continous improvement of the crystal characteristics from batch to batch : Improvement of dimensions Improvement of the transparency (no more core defect) Exceptional rejection for bad radiation hardness The results on first 1000 preproduction crystals are very encouraging