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Novel 3D micro-structuring of diamond for radiation detector applications : enhanced performances evaluated under particles and photons beams . B.Caylar 1 , M.Pomorski 1 , D.Tromson 1 , José Alvarez 2 , P.Bergonzo 1. 1 CEA-LIST, French Atomic Energy Commission, FRANCE
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Novel 3D micro-structuring of diamond for radiation detector applications : enhanced performances evaluated under particles and photons beams. B.Caylar1, M.Pomorski1, D.Tromson1, José Alvarez2, P.Bergonzo1 1CEA-LIST, French AtomicEnergy Commission, FRANCE 2Laboratoire de Génie Electrique de Paris , France IUMRS-ICEM 2012 | 25 SEPT 2012
Context • Diamond detectors in High EnergyPhysics • All LHC experiments already use diamonds for beam monitoring or as pixel detectors • CMS is building Pixel Luminosity Telescope • 48 scCVD pixel modules (5 mm x 5 mm) • ATLAS is building Diamond Beam Monitor • 24 pCVD pixel modules (21 mm x 18 mm) • Upgrade plans include diamond as candidate for innermost pixel tracker layer(s) Pixel Detectors Beam Monitors Marko Mikuž “Diamond Sensors”,ICHEP (2012) IUMRS-ICEM 2012 | 25 SEPT 2012
Context • Luminosityprevisions At LHC, luminosity will increase more and more in the following years IUMRS-ICEM 2012 | 25 SEPT 2012
Context • Radiation hardnessisstill an issue in diamond • NIEL inducesbulkdefects… • Higher luminosity • Faster signal decrease • Development of advanced detectors • Diamond detectors • Silicon 3D detectors • Why won’t we try to build the radiation hardest • detector ever ? A 3D Diamond Detector… Before irradiation After 1.2 x 1014 n.cm-2 After 1.97 x 1014 n.cm-2 Signal decrease IUMRS-ICEM 2012 | 25 SEPT 2012
Context • Whatis a 3D detector ? • Planar geometry • QMIP = 18000 e-h pairs • TOF = 5 ns • 3D geometry • QMIP = 18000 e-h pairs • TOF = 200 ps 50µm 500µm • Analyticallycalculatedcurrentsgenerated by a MIP IUMRS-ICEM 2012 | 25 SEPT 2012
Context • Whatis a 3D detector ? • Planar geometry • QMIP = 18000 e-h pairs • TOF = 5 ns • 3D geometry • QMIP = 18000 e-h pairs • TOF = 200 ps 50µm 500µm CCE drops by 53% CCE drops by 5% • Analyticallycalculatedcharge collection IUMRS-ICEM 2012 | 25 SEPT 2012
Burriedelectrodes • Laser setup and fabrication • Electrodes are processedusing laser-inducedgraphitization • Wavelength : 800nm • Repetition rate : 1kHz • Pulse length : 100fs • Spot size : 10µm IUMRS-ICEM 2012 | 25 SEPT 2012
100µm Burriedelectrodes • Laser setup and fabrication Processimprovement over the pasttwoyears Dec 2010 100µm Feb 2011 • Femtosecondlaser • Diameter: 5µm • Pitch < 35µm • YAG Laser • Hollow, conicalshape • Diameter: 100µm • Pitch : 300µm • UV Laser + x10 Lens • Diameter: 75µm • Pitch : 200µm • UV Laser + x20 Lens • Diameter: 20µm • Pitch : 150µm 100µm 100µm Jun 2011 Apr 2012 IUMRS-ICEM 2012 | 25 SEPT 2012
Burriedelectrodes • Whyisfemtosecond laser somuchbetter ? • A two-step process • Producing a graphitic seed at the surface • Excitation of a large number of valence electrons via multi-photon absorption • Energybarrierdecreases • Phase transition Diamond- Graphite • Propagation of laser supported graphitic wave No heataccumulation T.V. Kononenko et Al – Rus’nanotech (2010) IUMRS-ICEM 2012 | 25 SEPT 2012
Burriedelectrodes • Structural characterization • Electrode Raman Analysis • Diamond • Border EHT = 5kV WD = 4.9mm Mag = 11.85k X IUMRS-ICEM 2012 | 25 SEPT 2012
Burriedelectrodes • Structural characterization Electrode mappingusingConductive probe AFM J.Alvarez, LGEP 200 kΩ 1µm 1µm ρ ~ 1 Ω.cm • AFM mapping • Resistancemapping • Resistance distribution in the mapping area IUMRS-ICEM 2012 | 25 SEPT 2012
3D Diamond detector • Optical microscopy Final detector - 45° tilted • scCVDsample Courtesy of CERN • Graphitization process is not yetoptimized – 70% success rate IUMRS-ICEM 2012 | 25 SEPT 2012
3D Diamond detector • Characterizationusing90Sr 90Sr experimentallowsyou to get MIP in yourlab IUMRS-ICEM 2012 | 25 SEPT 2012
3D Diamond detector • Characterizationusing90Sr Charge collection efficiencymeasurement • HV = -200V 3D Detector seems to have a 65% CCE at maximum • Most probblyartificiallycut by electronicshaping time (200ns) • Under investigation IUMRS-ICEM 2012 | 25 SEPT 2012
3D Diamond detector • Characterizationusing synchrotron micro-beam Side raster scan - 15keV photons - 3µm spot 9,500 300µm 300µm • HV = -200V Synchrotron µ-beam • Charge iscollectedwithin the wholethickness IUMRS-ICEM 2012 | 25 SEPT 2012
3D Diamond detector • First application Timing measurementduring GAMMHADRON beamtime – 25MeV protons • Hodoscope vs 3D detector • Hodoscope vs plastic • Time resolutionisbetterusing 3D diamond detector IUMRS-ICEM 2012 | 25 SEPT 2012
3D Diamond detector • Summary Wemanaged to… • Produceelectrodeswithsuitable dimensions for detectors applications • Check thatelectrodes are graphitic and conductive • Check thatsuchelectrodes are active and allow charge collection • Use thatnextgeneration detector in a timing application Nowweneed to… • Optimize the graphitization process and get 100% efficiency in graphitization • Irradiate the samples and measuretheir radiation hardness IUMRS-ICEM 2012 | 25 SEPT 2012
Thanks for your attention ! IUMRS-ICEM 2012 | 25 SEPT 2012
3D Diamond detector • Acknowledgements People @ CEA-LIST • Nicolas Tranchant • Hassen Hamrita • Nicolas Vaissière • Céline Gesset • Externalco-workers • Alexander Oh • Cinzia Da Via • Lin Li • David Whitehead • NatkoSkukan • Thorsten Wengler IUMRS-ICEM 2012 | 25 SEPT 2012
Burriedelectrodes • Whyisfemtosecond laser somuchbetter ? • A two-step process • Producing a graphitic seed at the surface • Excitation of a large number of valence electrons via multi-photon absorption • Energybarrierdecreases • Phase transition Diamond- Graphite • Propagation of laser supported graphitic wave No heataccumulation Energybarrierdecrease Multi-Photon Absorption C.Z. Wang et Al -Phys. Rev. Lett. 85, 4092 (2000) T.V. Kononenko et Al – Rus’nanotech (2010) IUMRS-ICEM 2012 | 25 SEPT 2012