PoS(TWEPP-17)092
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er (LHC) tunnel. The
reports do exist for visible spectrum power LEDs powerLEDs spectrum visible for exist do reports ND ND 4.0). -
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NoDerivatives 4.0 International License (CC BY 4.0(CC License NoDerivatives International - 0 0 Gy and no failures were observed. This paper describes the basic design, presents
Trikoupis
juan.casas TE/CRG TE/CRG NonCommercial - - -
and the reduction in light output versus dose is coherent with the results presented in this paper. Dose Integrated Total a to up facility CHARM CERN’s in irradiated were units lighting Prototype (TID) of 87 tests field radiationof and the effects on the LEDs luminance. A A LED (Light Emitting Diode) based directional lighting system has been designed to indicate the best evacuation direction for applications like the Large Hadron Collid design includes constraints for redundancy required selection by radiation effects. Most of the literature for radiation on effects LEDs concern digital by safety systems and for recent some although systems, communications components 14September 2017
- mail: mail: [email protected] Copyright owned by the author(s) under the terms of the Creative Commons of the under the by terms owned the Creative Copyright author(s) - -
Speaker 1 Attribution for Particle Physics on Electronics Workshop Topical 11 Santa CaliforniaCruz,
1211 Geneva23,Switzerland 1211 E Nikolaos CERN Geneva23,Switzerland 1211 E emergency evacuation directional lighting directional evacuation emergency Casas Juan CERN Design and radiation tests on a LED based based LEDa on tests and radiation Design
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ed ed by tage tage drop of d d by the tunnel ng ng exit shaft when M manufactur
- J. Casas N. Trikoupis & E2 model manufactured E2 model manufactured - . In these conditions the 2
protected area and only passive - , this value is acceptable to personel personel to acceptable is value this , 2
uminous flux through the IRIS lens would would lens IRIS the through flux uminous ea ea to about 57 cm
350 m and of limiting the amount of glare while while glare of amount the limiting of and m 350 2 n a radiation environment. The use of directional he light source [2]. source light he
section of 0.5 mm2) produces a maximum vol -
) and within distances of 5 m or less, may be dangerous to 2
nd has 9 access shafts. The LHC safety system provides, in its present status, status, present its in provides, system safety LHC The shafts. access 9 has nd relatively relatively low permit to currents design a radiation robust for scheme which the safety Directional Lighting Design Lighting Directional Introduction
The The In an application like the LHC, distances up to 2 km may exist between the radiation To address theglare, XLamp LEDs are To used with a strong very derating (current of 10 mA At At the nominal LED current of 350 mA, the red and green LEDs produce an approximate The light emitting elements The are lightelements emitting red XP and green LEDs XLamp® The directional lighting uses red and green lights to forbid or permit circulation in a given Directional Directional lighting that guides the personnel present in confined spaces would be a useful Main Components Tunnel and Radiation Constraints Radiation and Tunnel
assuming assuming copper cables with a cross installed. supply 48Vdc the to compared low very is considerations, practical from which, Vdc 1.5 control equipment and dc power supply stays in a 1). (Fig. area hazardous the in located are diodes) and (resistors components radiation protected zone and the directional lighting. The associated cable resistance (up to 150 ohm lenses in parallel to increase the light emittance ar cd/m 10'000 below is surface lens the at measured luminance [3]. lights red traffic for found range tthe within and is nearby working 2.2 be far too bright (approximately 300’000 resulting cd/m in glare t to proximity in close working personnel that exceeds the upper vision tolerance threshold and 5 respectively for mA the red and green LED) and by using per color up to five Ledil IRIS by by Cree®. The LED light is guided using Maximum Half a Width Full lens a with and material model methacrylate) (Polymethyl FCN12790_IRIS PMMA of made Ledil, of 29°. angle (FWHM) l These lm. 100 and lm 60 respectively of flux luminous contradictory requirements of being visible over over visible being of requirements contradictory in proximity close working 2.1 2. direction inside the tunnel. The maximum separation between the lights is limite personnel for locations typical although m 320 about of sight of line maximum a has that curvature and equipment will limit it to less than 220 m. The directional lightning shall satisfy the below ground level a level ground below system lightning directional a although tunnel the in present personnel the to protection excellent would be a useful addition to avoid personnel going initially towards the wro is triggered. alarm an evacuation 1. that manufacturer a find to able not were authors the however procedures, evacuation for addition provides such equipment qualified to operate i lighting was investigated during the tests performed in 2014 helium release simulating [1] into an the 27 accidental km circumference LHC liquid accelerator tunnel that lies about 100 m LED based emergency evacuation directional lighting LED evacuationbased directional emergency PoS(TWEPP-17)092
ting ting
110 110 meter with an -
J. Casas N. Trikoupis &
of five LEDs irradiated. LEDs five of ensity ensity reduction is negligible from a the observation angle either encloses
3 , which is an acceptable figure producing tolerable clockwise direction. LCH tunnel view of the green green of the view tunnel LCH direction. clockwise ure of the four cluster cluster four the of ure 2 -
ger distances, the tunnel lights might perturb the meter. the perturb might lights tunnel the distances, ger
and red directional lighting from a distance of 336 m. of a distance from lighting directional and red minance minance does not exceed 10’000 cd/m Figure 1: Electrical schematics and pict and schematics Electrical 1: Figure The tests performed Thein tests theperformed is tunnel that directional lighting the demonstrate visible clearly The The measurement of luminance assumes that The directional lightning shall be clearly visible from at least the tunnel line of sight that has has that sight of line tunnel the least at from visible clearly be shall lightning directional The gure 2: Measured (circles) and calculated (lines) luminance versus distance. Empty/Filled Empty/Filled distance. versus luminance (lines) calculated and (circles) Measured 2: gure Fi circles correspond to the clockwise/counter the to correspond circles glare to personnel working in close proximity to the source of light [3]. light of source to the proximity in close working personnel to glare of 10 m about 50% of the surface is not luminous and the measured luminance is underestimated is underestimated luminance measured the and luminous not is surface the of 50% about of 10 m lon At 2. 50%, figure by within a distance up to the maximum line of sight in the close circular Within proximity region. the lu and the light. emergency The luminance measurements rely on a Minolta LS acceptance angle of 1/3°. Each red and green LED luminous flux is estimated to be respectively lm. and 2 1.7 lm about distance a at area; observation the on uniform is luminance the that or source light the completely in the remote location and the corresponding of view point physiological light int ligh neon the by produced spots with brighter to 6 cd/m2 about of 4 luminance a background LED based emergency evacuation directional lighting LED evacuationbased directional emergency PoS(TWEPP-17)092
by by the
, the green green the , 2 ransmission ransmission
E2 LEDs. Blue LEDs LEDs Blue LEDs. E2
J. Casas N. Trikoupis & - The The luminance of each
The irradiation campaign campaign irradiation The E2 radiation tests results are 20 MeV proton/cm MeV 20 -
was was measured each time by the 12 110, figure 3. figure 110, -
by about 18% and 47% for 340 keV proton proton keV 340 for 47% and 18% about by [4]. The InGaN is the same technology used used technology same the is InGaN The [4].
2
4 . Up to a dose of 2 x 10 x 2 of dose a to Up . proton/cm 2 12 periods shown in gray shown in periods HEH/cm
2 the relative luminance versus TID (figure 3). (figure TID versus luminance relative the E2 red and green LEDs and their lens. associated Each cluster was 1 - and 5 x 10 x 5 and
12 eans that this reduction is not significant from a physiological point of of point a physiological from significant not is reduction this eans that
E2 LED that during the CHARM test shows a decrease of about 30% for -
Radiation Tests Radiation
At At the end of the irradiation the PMMA material transparency was not affected Both red and green LEDs showed a decrease in luminance although this reduction in light The literature for radiation effects is mostly concerned with digital data t There There were five stops of the irradiation and the luminance The The radiation tests were started in November 2014 in the CHARM irradiation facility on r clusters r of five clusters Cree XP Figure 3: Luminance variation versus TID. Accidentally all LEDs were kept ON during the the during ON kept were all LEDs Accidentally TID. versus variation Luminance 3: Figure
accumulated radiation dose. radiation accumulated a dose of 870 Gy and 2.3 x 10 x 2.3 and Gy 870 of dose a decrease a shows (AlInGaP) LED red the while radiation the to insensitive almost is (InGaN) LED of 30% of its light output power [5]. Qualitatively the Cree XP coherent with data in reported the a comparison cannot litterature, although quantitative be done spectra. radiation and different the LEDs for manufacturers different of because applications applications that typically use different light frequencies and different LED material. However XP Cree the for used as materials same the for exist do reports recent some luminance its decrease to reported are InGaN of made 1x10 respectively of doses for the green Cree XP intensity intensity (about 80% for the red color) could not be recognized m it area, by test the accessed the different persons that view. Accidentally all LEDs were kept ON during 3). figure two irradiation periods (grayed areas in slightly smaller than the lens area when using the Minolta LS the Minolta using when area lens the than smaller slightly duration limited a imposed stops irradiation The conditions. geometrical same the in person same policy requiring to perform the as measurements fast as possible in resulting variation a of large on seen as data luminance the fou OFF. kept were two irradiation, the during and, independently powered duration was 22 days and the Integrated Total surface Dose viewing (TID) was a to 870 Gy. corresponding m 5.5 about of distance a at measured was LED and lens single LED based emergency evacuation directional lighting LED evacuationbased directional emergency 3. PoS(TWEPP-17)092
- USA, , 1 - has been been has
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J. Casas N. Trikoupis & -
Light Emitting Diode (LED) Traffic Signals, Light Emitting DiodeTraffic (LED)
Q60 (2016). 5 - preparing the prototypes and in performing field tests. field in performing and prototypes the preparing , Vernon Odom Ph.D., Judges,Lawyers & ISBN 978 Vernon ,
nt of view and if required the luminosity is easily increased by an an by increased easily is luminosity the required if and view of nt Ionizing Radiation Damage Effects on GaN Devices
— fects on commercial European light emitting light diodes, European fects on commercial Final report on the Controlled Cold Helium Spill Test in the tunnelLHC at Helium Cold Spill on Test theFinal Controlled report provides provides ample robustness against failures like for instance parallel
07/Task 246, 2009. 07/Task
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Review Forensic Vision with Application with to Highway Safety with CD Vision Forensic Night visual performance Protons ef Protons 3, 2008 - Chanat et al., - f luminance (e.g. the green color was as bright as new) but the uncertainty of the 54
- , Advances in Cryogenic Engineering: Cryogenic Engineering Conference, Tucson, AZ, AZ, Advances in Cryogenic Engineering: Cryogenic ,Engineering Tucson, Conference,
Conclusions Acknowledgements
The The authors are indebted to S. Grau for her technical concerning safety comments controls The TID TID The does indeed produce a reduction of the LEDs luminance, but this reduction is not The present design A directional lighting to permit or forbid personnel circulation in a given direction given a in circulation personnel forbid or permit to lighting directional A After 2.5 years the lights were measured again, qualitatively the lights recovered about 20% 20% about recovered lights the qualitatively again, measured were lights the years 2.5 After Solid State Science and Technology, 5 (2) Q35 SolidTechnology, State Science and M. Boutillier, presentation, 2015. Chapter 6.6 D 033264 J. et al, D.Replacement Bullough Processes for Project20 NCHRP S. J.Pearton et al, L. DufayL. CERN 2015 M. Green et al,
[5] [3] [4] [1] [2] References 5. in effort his for Diez F.J. to and hardware can be performed by measuring the supply current that shall be able to detect open or shortened etc. open contacts, LEDs, poi physiological a from visible current. supply the of increase distances distances in an environment like the LHC tunnel proximity. in close working and personnel has an acceptable amount of glare to supplies cabling parallel failure, LED of case in operation permit to circuitry LEDs the of supplies obs be degradation any that requires design robust A etc. contacts, open with cope to of the loss o luminance. measured the % on 50 of errors yield easily can angle measuring 4. designed. Field tests thatconfirm the light intensity is compatible with good visibility over long LED based emergency evacuation directional lighting LED evacuationbased directional emergency