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Radiation Simulations in CMS. Pushpa Bhat, Nikolai Mokhov, Anil Singh* Fermilab Batavia, IL * Panjab Univ., India. MARS Simulation Studies. Latest round of efforts
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Radiation Simulations in CMS Pushpa Bhat, Nikolai Mokhov, Anil Singh* Fermilab Batavia, IL * Panjab Univ., India
MARS Simulation Studies • Latest round of efforts • Started in 2007, to re-evaluate beam-induced radiation in CMS, particularly in the pixel detector due to concerns of safety in typical beam-accident scenarios – e.g., single module abort kicker prefire initiating asynchronous beam abort • Scenarios Studied • pp collisions at L=1034 cm2sec-1 • Machine-induced Backgrounds: beam-gas, beam halo • Beam Accidents (potentially the most risky) • Simulation Results: Maps and tables of radiation dose, particle fluence, energy spectra are available. Results in (r,z) stored in a database. Web Tool exists to extract numbers. Over a dozen presentations given at CMS mtgs. • CMS Notes: CMS CR-2009/262 (pp results conf rep for tracker) CMS Note-2009/000 (Beam accident studies) Detailed CMS Note on pp results in preparation
The Detector MARS Model BCS BCM1 HB HE
Radiation Dose (Gy/s) @L= 1034cm-2 s-1
Absorbed Dose (50 fb-1) 105 104 103 102 10 1 10-1 10-2
Comparison with TDR results 105 104 103 102 10 1 10-1 10-2 Note: Overlaid contours (TDR; Mika H) are for 500 fb-1 while the bottom plot (MARS, this study) is for 50 fb-1
Absorbed Dose 2E-4 Gy/s 1MRad / 500 fb-1 HE HB R
Neutron Fluence HE HB R
HF Region Max. Dose >100x than in HE
Dose/Fluence Web Calculator Returns results for a given radius, z and L.dt using data in a database
Dose/Fluence Web Calculator • The database and the tool are being extended.
Dose (Gy) 100 fb-1 Finer granularity
Summary • Extensive radiation simulations have been done for the CMS detector, over the past few years using MARS15. • pp at 14 TeV, 10 TeV, 3.8T, 0T • preliminary beam-gas, beam-halo • Beam accidents • Lots of results and tools exist!