1. 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
24/09/09
B. Todd Huffman

2. 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
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B. Todd Huffman

3. The two locations: 60Co g rays
RITA 0.6kGy/hr
BRIGITTE 20kGy/hr
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B. Todd Huffman

4. Previous High-dose test result
Draka Commercial
Draka 3
Infinicor
Draka RHP-1 SRH
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B. Todd Huffman

5. 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
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B. Todd Huffman

6. RIA and temperature, 1st 6 hours.
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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!
24/09/09
B. Todd Huffman 8

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
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B. Todd Huffman

9. Container to Actively Cool Fibres
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B. Todd Huffman

10. InfinicorSX+ Temperature Effects
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B. Todd Huffman

11. Draka Fibre Temperature Effects
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B. Todd Huffman

12. 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.
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B. Todd Huffman

13. Before
0.01 dB
0.05 Deg. C
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B. Todd Huffman

14. after
0.7 dB
0.05 Deg. C
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B. Todd Huffman

15. 0.05 dB
Before
1 Deg. C
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B. Todd Huffman

16. after
0.2 dB
1 Deg. C
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B. Todd Huffman

17. Comparisons, InfinicorSX+
T = +300 C
Dose = 65 kGy(Si)
Gamma source at room temperature. Variation is from prev. Stability limitations.
T = C
Dose = 30 kGy(Si)
24/09/09
B. Todd Huffman

18. Comparisons, InfinicorSX+
T = +300 C
Dose = 65 kGy(Si)
Gamma source at room temperature. Variation is from prev. Stability limitations.
T = C
Dose = 30 kGy(Si)
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B. Todd Huffman

19. Draka RHP-1 SRH fibre T = -40 C Total Dose ~ 15 kGy(Si) T = -250 C
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B. Todd Huffman

20. 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
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B. Todd Huffman

21. 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.
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B. Todd Huffman

22. 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.
24/09/09
B. Todd Huffman

23. 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.
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B. Todd Huffman

24. 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
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B. Todd Huffman

25. Next Slides are backup slides
End Of Talk
Next Slides are backup slides
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B. Todd Huffman

26. Optical Patch cables Splitter No Longer used! Conn. 24/09/09
B. Todd Huffman

27. System Stability tests – last year
Ran system for extended time periods.
Found stability limitations
Extensive tests by J. Hanzlik showed the optical splitter was the main cause of instability.
±1.5 dB absolute stability limitation for MM fibres.
24/09/09
B. Todd Huffman

28. Stability of test system
Output from multi-mode fibre (coupler in system)
VCSEL
coupler PD
PD = photo-diode
1.5 dB
0.2
= connector
Output from multi-mode fibre (no coupler in system)
-.11
VCSEL PD dB
-.15
PD = photo-diode
= connector
Removing coupler seems to improve stability of MM system
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B. Todd Huffman 12

29. Stability by the Numbers
Multi-mode fibre InfinicorSX+
RMS variation using 1x4 optical splitter
~0.15 dB
RMS variation of single channel – no splitter
~ dB
Single Mode fibre SMF-28
RMS variation using 1x4 optical splitter
~0.014 dB
RMS variation of Single channel
~0.042 dB
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B. Todd Huffman

30. You can even watch it turn on.
RIA oscillations increase in amplitude
Temp. oscillates & rad. starts
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B. Todd Huffman

31. Semi-cold Draka Run
-4 deg C
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32. Behavior of Reference fibres
Attenuation, dB
Attenuation, dB
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B. Todd Huffman

33. InfinicorSX+ Temperature Effects
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B. Todd Huffman

34. Draka RHP-1 SRH fibre
T = -40 C
T = -250 C
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B. Todd Huffman