HF QUARTZ FIBER Y.Onel , J.P.Merlo, K.Cankocak, I.Dumanoglu, I.Schmidt and A.Penzo

Quartz Radiation Damage Studies Electron Irradiation Tests: Dumanoglu et al. “Radiation-hardness studies of high OH content quartz fibres irradiated with 500 MeV electrons” Nucl. Instr. Meth. A 490 (2002) 444-455 Proton Irradiation Tests: Cankocak et al. “Radiation-hardness measurements of high OH content quartz fibres irradiated with 24 GeV protons up to 1.25 Grad“ Nucl. Instr. and Meth. A 585 (2008) 20–27 Neutron and Gamma Irradiation Tests: U. Akgun et al. “Radiation Damage in Quartz Fibers Exposed to Energetic Neutrons” Submitted to IEEE Transactions on Nuclear Science.

Expected HF Fiber Exposure and Scenario Luminosity Ring 1-5 Ring 6-9 Ring 10-13 LHC (at 1034) 1 Mrad/year 10 Mrad/year 100 Mrad/year Phase I (1.5 *1034) 1.5 Mrad/year 15 Mrad/year 150 Mrad/year Phase II (3 *1034) 3 Mrad/year 30 Mrad/year 300 Mrad/year SLHC (1035) 1 Grad/year These numbers are without recovery of fibers. We expect the fiber to recover at least 20% at each shutdown. QP Fibers can survive at 1 Grad at high eta. The PMTs have sensitivity range nicely fitting with Fiber “sweet range” of 380 nm-580 nm). PMT HV adjustment can easily make up for lost light intensity due to radiation.

Estimate of radiation damage and recovery versus dose in HF quartz fibers tirr (days) 1 2 3 5 10 20 50 100 150 200 2000 Dose (Mrad) 0.5 1.0 1.5 2.5 5.0 25 75 1000 A (dB/m) 0.156 0.211 0.252 0.316 0.428 0.581 0.869 1.179 1.410 1.600 2.754 Signal loss (%) 5.7 7.7 9.1 11.3 15.0 19.8 28.0 36.1 41.5 45.6 65.0 Increase aft.1h (%) 1.7 1.9 2.1 2.3 2.7 3.0 3.6 4.0 4.3 4.5 4.1 aft.8h (%) 3.3 3.8 4.4 5.1 6.2 7.1 8.1 7.4 aft.1d (%) 3.7 4.7 5.6 6.6 9.0 9.8 10.9 10.2 af.10d(%) 5.8 6.8 8.5 10.4 13.4 16.1 17.9 19.2 19.4

Assembly of Raddam fibres spacer To PMT Raddam fiber From laser Assembly tool

HF Towers raddam equipped (A) Wedges 1-18 1-1 2-14 2-5 towers EM2 HAD4 EM6 HAD8 EM10 HAD12 EM13 (B) Wedges 1-14 1-5 2-9 2-10 towers HAD2 EM4 HAD6 EM8 HAD10 EM12 HAD13 Within in a wedge 7 towers are instrumented with these sample fibers. In total there are 56 sample fibers in the entire system which will provide radiation damage information [1].

SUMMARY The RADDAM system has been tested with LHC-HCAL DAQ installed at the CMS experiment. The RADDAM on-line system and the quart fiber irradiations at LIL, PS and ANL including all equipment were funded IOWA VP of reseach. QP fiber will survive up to 1 Grad and more(10 years of LHC running at 10**34). QQ fibers will last longer and rings10-13 High Eta Towers—eta 4.2-5.2) The results of irradiation of one fiber in a PS beam at high dose rate (2.6 Mrad/hour) with HCAL-DAQ read out agreed with previous transmission measurements[1][2]. The source calibration results done at a post data taking time t > 1h have to be corrected to reduce systematic error. With the increase of dose (0.5 Mrad/day at full luminosity near  = 5) the raddam device monitors the light signal losses near 450 nm and estimate the correction to apply to source calibration results. Nucl. Instr. Meth. A 490 (2002) 444-455, Nucl. Instr. and Meth. A 585 (2008) 20–27.