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Radiation Environment at AWAKE. Eduard Feldbaumer, Silvia Cipiccia, Helmut Vincke. Outline. Simulation parameters Prompt dose rate Damage to Electronics Radiation background at Lanex screen Summary. Proton source routine. Momentum 400 GeV /c
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Radiation Environment at AWAKE Eduard Feldbaumer, Silvia Cipiccia, Helmut Vincke
Outline • Simulation parameters • Prompt dose rate • Damage to Electronics • Radiation background at Lanex screen • Summary
Proton source routine • Momentum 400 GeV/c • Momentum spread 1.2 GeV/c(1 sigma) • Initial distr. (1 sigma): • x, y = 0.02 cm • z = 13.9 cm • Divergence (mrad): • small = 0.024 • large = 0.36
Plasma Cell 40 mm • Rubidium gas • r = 20 mm • Plasma cell - Steel • l = 10 m • d = 2 mm • Offset 5 mm up • Proton shielding - Steel • l = 6 m • r = 15 mm • d = 1 mm e- p+ Plasma cell Vacuum chamber Cut through plasma cell
Prompt dose – Nominal operation • Nominal operation • Beam intensity: 3E11 p+/bunch • Repetition rate: 1/30 Hz AWAKE CNGS
Damage to electronics • Cumulative damage COTS hardened electronics Semiconductors Polymers Ceramics Metals and alloys • Stochastic damage • From M. Brugger ‘Radiation Damage to electronics at the LHC’, IPAC2012: • Commercial equipment: ~107 HEH/cm2/year M. Brugger presentation for CERN FLUKA user meeting 2008
Dose equivalent [mSv/bunch] Shielding r = 10 mm Shielding r = 3 mm Shielding r = 15 mm
1 MeV n-eqfluence per year Shielding r = 3 mm Shielding r = 10 mm Shielding r = 15 mm safe limit 1013 n/cm2
HEH fluence per year Shielding r = 3 mm Shielding r = 10 mm Shielding r = 15 mm safe limit 107cm-2
Updated geometry Lanex Screen (Gd2O2S) Plasma Cell from ErdemÖz Bending Magnet Separation wall from Sylvain Girod Inner & outer steel tube 3.5 cm Rubidium Thermal oil Microtherm layer
Prompt dose rate • No significant changes in prompt dose rates no difference for D2E expected
Electron & Proton simulations • 2 GeV electron beam from plasma cell bent by the bending magnet • 400 GeV proton beam (3e11 p+/bunch) through the plasma cell
Lanex screen: Noise level • Energy deposition per electron (GeV/cm3) • Energy deposition per proton bunch (GeV/cm3) Electron: ~ 5x10-5GeV/cm3 Proton bunch: ~ 50 GeV/cm3 Signal:Noise = 10 ~ 107 e- ~ 2 pC
Summary • Damage to Electronics in vicinity of Electron Spectrometer • cumulative effects due to dose and neutron flux negligible • SEE: HEH fluencelimit exceeded close to beam • Current geometry updates: • No major changes in terms of dose and D2E • Lanex screen: • signal to noise ratio 10: ~ 2 pC e- (2 GeV) • Strongly dependent on final geometry