1 / 17

Detectors for LHC crystal tests

Detectors for LHC crystal tests. L.Burmistrov , G.Cavoto , F.Iacoangeli , F.Murtas,V.Puill INFN & LAL Apr 24 th 2013. Summary. LHC BLM Ionization chamber, they come “for free” anytime you install a new object on the accelerator. Detector for channeled beam in vacuum

alvin-bond
Download Presentation

Detectors for LHC crystal tests

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Detectors for LHC crystal tests L.Burmistrov, G.Cavoto,F.Iacoangeli, F.Murtas,V.Puill INFN & LAL Apr 24th 2013

  2. Summary • LHC BLM • Ionization chamber, they come “for free” anytime you install a new object on the accelerator. • Detector for channeled beam in vacuum • Cherenkov light based detector • Diamond BLM

  3. Concept • Use a well polished quartz Cherenkov radiator to intercept channeled beam • 1 cm thick • BTF measurements: • Cherenkov light in 0.5 mm quartz fiber: • 0.3 pe/0.3mm/mip with SiPM (40% QE) -> 10 pe/mip • Validation of Leonid’s G4 simulation! • 100 particles channeled/bunch -> percent level measurement! • See Leonid’s presentation • Quartz bar in vacuum • Need to design vacuum-air interface to bring light outside • Attach silica fibers (in air) to the quartz bar • Bring light far away from beam pipe (few m) to a PMT • Bring PMT signal very far (hundred m) to electronics • Motorization and beam pipe insert similar to goniometer • Retractable finger

  4. Orientation • Nov 12 BTF measurements: • 46 deg should be optimal to collect “direct” light LEONI FiberTech ALL SILICA AS 400/440 UVPI external diameter : 0.465 mm core diameter : 0.400 mm Cladding Diameter : 0.440 mm Cladding doping: Flourine Coating Material : polyamide NA = 0.22 attenuation: 0.008dB/m Relative angle particle-fiber axis • Overall difference • due to SiPM – fiber • optical coupling • Might we need a rotation stage to orient the bar ? (it could be good in case of high Z ions!)

  5. See Leonid’s presentation Device layout Geant 4 simulation good to assess the feasibility. Each optical interface need a specific hardware test

  6. Vacuum-air interface • Sketching quartz support and flange • To be inserted in a mechanicalsystem similar to piezo-gonio. • Realizing in a single piece • Fiber bundle • Fiber bundle +viewport • Fiber bundle + viewport +finger • [LEONI] viewport quartz

  7. Detector location A.Lechner slides Dec 2012 Max Dose (close to pipe) 100 kGy/year 1014 neutron/cm2/year (thermal neutron) Moving detector (PMT) to a far location (on the ceiling?) Readout electronics can be hundred meters away (need coaxial cables for signal and HV supply)

  8. Readout sketch See Veronique’s slides • Metal dynode or Multi-ChannelPlate • [expensive but <100 ps resolution! ] • 20% QE in blu-UV region • Require quartz window (to be transparent to blue) Photodetector: PMT COAXIAL cable

  9. Rad hard silica optical fiber ALL SILICA AS600/660UVST tr Core 600μm ± 2% Cladding 660mm ± 2% ACRYLATE Coating 770μm ± 3% Buffer 920μm ± 5% Attenuation @350nm <=0,06dB/m Operational in 200-1200 nm range 18 rad/s (0.3 rad/s LHC worst) • NB: Silica quartz fiber have good attenuation • in blu-UV but expensive (10 eur/m!)

  10. Radiation resistance of PMT • Metal dynode PMT: rad hard • Quartz window OK • Same for the radiator ? • A custom HV partitorsystem should be done • Redo standard Hamamatsu with rad hard passive components Need PMT irradiation test (proton at PSI)

  11. Effect of radiation on PMT window From Hamamatsu’s PMT handbook. Glass Window must be absolutely avoided instead.

  12. Background/noise • Scattered particles hitting the radiator • Produce Cherenkov light too • Use two “veto” radiator (subtract light seen there) : • need (at least) three identical channel • em. noise induce by beam ? • Is synchronization with machine available ? Is RF signal available at the electronics location ?

  13. “On board” calibration tools • LED light • Measures the stability of the gain • Inject light into the bar • use one special optical fiber • Does not depend on the stability of the LED!!! • Inject light at two point of the bar • Measure attenuation length variation of the bar

  14. Crucial tests • Optical interface are critical to preserve the Cherenkov photons • Need dedicated hardware test ! Simulation cannot be trusted… • Such device require an accurate validation at • BTF (beam of bunched electron – 500 MeV) • Can simulate the arrival of 1-10-1000 mip within 2ns. • Absolute calibration possible with mips • SPS • Test the full device is SPS with circulating beam • Is this compatible with LHC schedule ?

  15. Diamonds • Observe fast losses close to crystal • Need fast electronics • Reuse some R&D done for GEM • Install on the exterior of the goniometer device • It might be useful to follow fine crystal movements • Reuse diamond detector used in UA9 Test at BTF in June

  16. Cabling… • Two Cherenkov devices • (3HV + 3 signal)x2 coaxial cables. • 1 (or 2) cables for LED PS • Low attenuation coaxial cables • They should run from the detector location to some UJxx area • 4 diamond sensors • 1+1 * 4 coaxial cables

  17. Comments • Need a final decision on crystal and detector (absorber) location • Crucial tests for Cherenkov • Choice of PMT/ irradiation test • Design of interfaces and test • Calibration with extracted beam

More Related