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SLHC Radiation Test Results. Preliminary measurements Versatile Link project from exposure to gamma rays at SCK-CEN B. Todd Huffman (speaker), J. Hanzlik, C. Issever, T. Weidberg. The Outline. Brief explanation of facility used SCK-CEN sources Test procedures then and now.
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SLHC Radiation Test Results Preliminary measurements Versatile Link project from exposure to gamma rays at SCK-CEN B. Todd Huffman (speaker), J. Hanzlik, C. Issever, T. Weidberg B. Todd Huffman
The Outline • Brief explanation of facility used • SCK-CEN sources • Test procedures then and now. • Some Previous results and motivation for temperature controlled tests • Tests of Mulit-mode fibres • Draka RHP-1 SRH • InfinicorSX+ • Conclusions B. Todd Huffman
RITA 0.6kGy/hr BRIGITTE 20kGy/hr The two locations: 60Co g rays B. Todd Huffman
Previous High-dose test result Draka Commercial Draka 3 Infinicor Draka RHP-1 SRH B. Todd Huffman
These Results are Good • Good Candidate MM fibres identified • InfinicorSX+ and Draka RHP-1 • Draka Fibre is under further development and will require future tests • But Limitations of Previous tests have prompted further studies. • Temperature dependence in particular B. Todd Huffman
RIA and temperature, 1st 6 hours. B. Todd Huffman 7
Previous research on RIA in fibre Single-mode Multi-mode 850 nm GRIN fibre at room temp (curve C) and -17 C (curves A & B) credit: Thériault Radiation effects on COTS laser-optimized graded-index multimode fibers exposed to intense gamma radiation fields Single-mode RIA as fcn of temp. credit: Kanamori et al. Transmission Characteristics and Reliability of Pure Silica-Core Single-Mode Fibers RIA is temperature-dependent! B. Todd Huffman 8
Cold Container designed • Uses Peltier cooling elements • 4 coolers – 15V and 7A operation • Direct connection to Draka fibre • DT = ~60 deg C • Able to remove ~40W heat load • Suitable only for low dose facility • Radiation Damage and heat load • Heat shed to the shielding water • Water ambient temp = 30 deg C. • Goal Maintain -250C B. Todd Huffman
Container to Actively Cool Fibres B. Todd Huffman
InfinicorSX+ Temperature Effects B. Todd Huffman
Draka Fibre Temperature Effects B. Todd Huffman
An interesting Temp. Radiation effect • Prior to radiation, fibre attenuation relatively insensitive to temperature variations. • RIA sensitizes fibres to temperature. • Particularly Dramatic with Infinicor fibres • Present, but less of an effect with Draka fibres • Keep in mind 50m of fibre are used. B. Todd Huffman
Before 0.01 dB 0.05 Deg. C B. Todd Huffman
after 0.7 dB 0.05 Deg. C B. Todd Huffman
0.05 dB Before 1 Deg. C B. Todd Huffman
after 0.2 dB 1 Deg. C B. Todd Huffman
Gamma sourceat room temperature.Variation is from prev.Stability limitations. Comparisons, InfinicorSX+ T = +300 C Dose = 65 kGy(Si) T = -23.30 C Dose = 30 kGy(Si) B. Todd Huffman
Comparisons, InfinicorSX+ T = +300 C Dose = 65 kGy(Si) Gamma sourceat room temperature.Variation is from prev.Stability limitations. T = -23.30 C Dose = 30 kGy(Si) B. Todd Huffman
Draka RHP-1 SRH fibre T = -40 C Total Dose ~ 15 kGy(Si) T = -250 C B. Todd Huffman
Attenuation Upper limits • Low doses extrapolate linearly up to SLHC tracker doses 375kGy. • CAUTION!!: upper limit • Lower dose rate in Tracker volume • RIA follows logarithmic scale at high dose • At -250C inside Tracker volume • InfinicorSX+ 1.1 dB • Warm result 0.24 dB • Draka RHP-1 0.6 dB B. Todd Huffman
Conclusions • Infinicor Fibre is Ge doped • Draka Fibre is F doped • No Ge used • Neither uses Phosphorous in their manufacturing process • F doped fibre (Draka) has better radiation performance even at cold temperatures • ~0.05 dB/m vs. ~0.08 dB/m after 30kGy integrated exposure. B. Todd Huffman
Conclusions • Are we Qualified for operation of these fibres at Cold Temperatures? • Definite Maybe. • Extrapolation very conservative, but very dodgy • Ideally we would obtain close to a full SLHC dose (~400kGy) cold • Brigitte can do this • Smaller volume. • Potentially higher heat load. • Peltier system would surely fail. B. Todd Huffman
Conclusions • We believe a CO2 thermal management system can achieve the same goal at the higher dose facility. • Studying the feasibility of this. • Back-up is to use dry-ice. • Previous tests show we obtain -780C for 24 hours even with heat load. • But, such a test would teach us little if fibre ends up with more than 1dB/m RIA. B. Todd Huffman
General future • Cold tests finished by April • Qualified two fibres • Re-qualify Draka fibre with higher bandwidth • Move to qualifications of PLC splitters, LC connectors, full cabling solutions • Mechanical tests B. Todd Huffman
End Of Talk Next Slides are backup slides B. Todd Huffman
Splitter No Longer used! Optical Patch cables Conn. B. Todd Huffman
Ran system for extended time periods. Found stability limitations Extensive tests by J. Hanzlik showed the optical splitter was the main cause of instability. System Stability tests – last year ±1.5 dB absolute stability limitation for MM fibres. B. Todd Huffman
PD PD coupler VCSEL PD PD PD = photo-diode Stability of test system Output from multi-mode fibre (coupler in system) 1.5 • Removing coupler seems to improve stability of MM system dB 0.2 = connector Output from multi-mode fibre (no coupler in system) -.11 VCSEL PD dB -.15 PD = photo-diode = connector B. Todd Huffman 12
Multi-mode fibre InfinicorSX+ RMS variation using 1x4 optical splitter ~0.15 dB RMS variation of single channel – no splitter ~0.0053 dB Single Mode fibre SMF-28 RMS variation using 1x4 optical splitter ~0.014 dB RMS variation of Single channel ~0.042 dB Stability by the Numbers B. Todd Huffman
You can even watch it turn on. RIA oscillationsincrease in amplitude Temp. oscillates& rad. starts B. Todd Huffman
Semi-cold Draka Run -4 deg C B. Todd Huffman
Behavior of Reference fibres Attenuation, dB Attenuation, dB B. Todd Huffman
InfinicorSX+ Temperature Effects B. Todd Huffman
Draka RHP-1 SRH fibre T = -40 C T = -250 C B. Todd Huffman