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

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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 :