1. PROBLEM: Radiation Dose Rate in IR2 When IR1 is Operating (and Vice Versa) Muon Dose Rate > 1 mRem/hr for 0.1% Collimated Halo

2. Interaction Region Radiation Safety System 1. Design Goals: Occupy both IR’s while beam is on the commissioning dump Occupy IR1 while IR2 has beam (and vice versa) 2. Method and Conditions: a) IR1 and IR2 have separate collimation sections, collimate 0.1% halo. b) Both tunnels have a 3m concrete wall to attenuate neutrons. c) Run MUCARLO to find the maximum muon dose rate in any 80x80 cm area. d) Use SLAC Radiation Rules: 100 mrem/yr for non-radiation workers <25 Rem/hr (3 Rem max. dose) in Maximum Credible Accident

3. Muon Tracks Reaching IR2 from a Single Source in the IR1 Beamline 18 m Steel Walls Block the Tunnels Muon Dose Rate in IR2 is >0.1 mRem/hr (too high) @ 1 TeV CM

4. Muon Tracks Reaching IR2 from a Single Source in the IR1 Beamline 5 m Magnetic Spoilers Fill the Tunnels Muon Dose Rate in IR2 is <0.05 mRem/hr @ 1 TeV CM

5. Muon Dose Rates in IR2 when IR1 has Beam Dose rate goal is <0.05 mRem/hr Shielding Condition 500 GeV CM1 TeV CM (mRem/hr) No shielding0.91.5 18 m steel walls0.030.12 5 m magnetic spoilers <0.010.04 Collimate 0.1% halo All sources, both beams

6. Beam Containment Design Hardware to keep the primary beam from entering an occupied IR 1. A series of protection collimators and stoppers such that all possible missteered beams are confined to a collimator or stopper. 2. All dipoles in the big bend and energy collimation sections locked off. 3. Each protection collimator and stopper has: a) A beam loss monitor set to turn off the beam if more than a few kW of power is lost. b) A burn-through-monitor which shuts down the accelerator if ruptured by the beam.