LHC Emergency Lighting
jm FORAY EN/EL/BT
Initial project :The current LHC emergency lighting system was designed and installed at the time of the LEP : Low Pressure Sodium type
- end of life technology- fixed at approximately 40m centres, which creates a region of total darkness
between them
Main objective : Find a new solution and evaluate the radiation effect.
Development of two test bench :- an active test bench in TSG46 & TSG45
- to evaluate the lifetime of different technologies
- a passive test bench - to evaluate the drift of luminosity.
Active TEST : performed from March 2011 to December 2012
Developed a test bench placed in TSG46aim : - Radiation tests on :
Power source : Current transformers
Voltage transformers + a Graetz bridgeLighting system :
PowerLed technologyStandard led technology
Samples have been qualified with an equivalence of radiation dose for a five year lifetime.
LED lamps setup
Acquisition rack with the RTU
IP camera for systems
Technical Ethernet network
Video server
48 pins cable – various signals; voltages, resistances, control signals for contactors, contactor states
Data acquisition with a remote Webcam + ANA/TOR signals
Active TEST : performed from March 2011 to December 2012
2011 2012 december 2012
installation installation removed in TSG 46 in TSG45 the test bench
low radiation high radiation
Conclusions: Radiation evaluation test has concluded for the development of a new safety lighting system :
To not use current transformers: Broken at ≈ 7×1012 HEH/cm2
Powerled technology and standard led not affected by the radiation
Safety lighting system powered by a transformer + Graetz bridge can be a
solution.
Passive TEST :
A test bench was constructed using a microprocessor and three sensors to characterise the optical performance of each LED sample tested. The test bench was housed in a sealed black plastic enclosure to prevent ambient lightning conditions influencing the results.The optical measurement package consisted of:
TiO2 300nm UV PhotodiodeBPW 34F Optical PhotodiodeBPW 21 Infrared Photodiode
devices under test:3 No. Zumtobel 2W LEDs, one of which continuously illuminated and irradiated in CNGS for 6 months to simulate an approximate LHC 5 year dose2 No. Zumtobel custom PMMA lenses, 1 of which was irradiated with the LED in CNGS1 No. Thorlux 3W LED1 No. Acriche 230V LED
Workflow:Initial
measurement of the noise (zero error)
Second measurement of the relative luminous flux
emittance
irradiation
Third measurement of the relative luminous flux
emittance
Datas comparison
Passive TEST :Conclusion :
0.0
10.0
20.0
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40.0
50.0
60.0
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90.0
100.0
Zero ErrorCalibration Set No. 1 31/08/11
Calibration Set No. 2 01/09/11
Calibration Set No. 3 02/09/11
Irradiated Sample
CNGS (No Lens)
Normal LED with
Zumtobel Dali PSU
21/09/11
LED with Directional Lens (CNGS irradiated) 01/09/11
LED with Directional
Lens (normal)
01/09/11
230V LED sample unit 22/09/11
Thorlux on custom PSU 06/10/11
Thorlux on Standard
Thorlux PSU 07/10/11
Overall Light Output
Average A0 IR Average A1 UV Average A2 Visible
0.0
10000.0
20000.0
30000.0
40000.0
50000.0
60000.0
70000.0
80000.0
Zero Error Calibration Set No. 1 31/08/11
Calibration Set No. 2 01/09/11
Calibration Set No. 3 02/09/11
Irradiated Sample
CNGS (No Lens)
31/08/11
Normal LED with
Zumtobel Dali PSU
21/09/11
LED with Directional Lens (CNGS irradiated) 01/09/11
LED with Directional
Lens (normal)
01/09/11
230V LED sample unit 22/09/11
Thorlux on custom PSU 06/10/11
Thorlux on Standard
Thorlux PSU 07/10/11
Light Output
Average Freqctr
The observed drop in light output as a function of the type of power supply was 43% for the Zumtobel fitting The observed drop in light output from the Zumtobel LED as a result of 6 months continuous illumination and exposure to a 5 year LHC radiation dose was 19.5%. The PMMA lens used in the CNGS trials suffered a performance reduction of 3.9% as a result of the radiation exposure
5 year performance = Initial performance x (57%) x (80.5%) x (96.1%)
5 year performance =44% Initial performance
Devices also installed in those locations where the radiation levels will be significantly higher (kGy/y and more) like in the collimation, injection, dump extraction and inner triplet areas.
Need to perform further tests at Fraunhofer institute + CEA to
To be schedule with EN/STI this year
Next Step :