1. Status of Phase II Energy Loss Studies 1. FLUKA with “simple” CERN-provided input file modeling ~40m around primary collimators used for all SLAC studies. Let “pencil beam” halo interact in primary vertical carbon collimator and study energy deposition in rectangular 25x80mm jaws at 10 sigma. –Assume 80% inelastic int. in primary, 2.5% in each jaw of secondary –Vary jaw material & provide energy deposition grid on jaw to ANSYS 2.5mm x 8mm x 5cm rectangular grid, mapped onto cylinder –Understand secondary particle content, energy & spatial distributions 2.Use CERN provided (V6_5_lowb lattice) ray files of halo interactions in H, V, and Skew primaries with secondary jaws at 7 sigma and re- calculate the energy deposition grids. 3. Study accident case: –Transverse extent of damaged region 4. Longer term goal of upgrading to current CERN input structure with much richer description of all devices in tunnel. L. Keller LHC Collab. Mtg., 15-17 June, 2005

2. Beam 1 Beam 2 Primary collimators First group of secondary collimators 40 m dipoles IR-7 Z (cm) X (cm)

3. Axial Distribution of Halo Interactions in the Second Primary Collimator (TCPH) Carbon

4. Axial Position of Halo Interaction Point vs. Distance from Primary Collimator Edge Why a sharp peak ≈ 1µ from the edge? Beam Jaw edge

5. Energy Spectra of Particles Hitting TCSH1 Keller: 2004-10-06 All Particles-7 

6. Spatial Distribution of Particles from TCPV at face of TCSH1 when Jaws at 7 sigma Upper right jaw Lower left jaw

7. Concentrating E_dep in the Front Part of the Jaws (Use CERN-provided ray files) Carbon pre-radiator Tungsten with carbon pre-radiator

8. Primary Collimator (source) TCSM.B6.L7 Jaws at 7 sigma TCSM.B6.L7 Jaws at 10 sigma Copper Al_2219 Copper Al_2219 TCP.D6.L7 (TCPV) 73 26 51 19 TCP.C6.L7 (TCPH) 61 22 49 19 TCP.B6.L7 (TCPS) 92 28 56 20 Power Deposition on First Secondary Collimator in 12 Min. Lifetime (kW per jaw) Notes: 1. Collimator data, ray files, and loss maps from LHC Collimator web page, Feb. 2005. 2. Must add contribution from direct hits on secondary jaws.

9. 2.5 cm Missteered beam (9E11 protons) on secondary Jaw What is the damage area in a missteering accident? Copper Jaw Cross section at shower max. Copper Fracture temp. of copper is about 200 deg C 3D ANSYS model, E. Doyle

10. Accident Case – jaw adjacent to the one being directly hit, ≈ 4 mm gap. This jaw may be damaged too. 840 deg C Fracture at 200deg C Copper 3D ANSYS model, E. Doyle

11. Another accident Case – Beam hits the horizontal primary collimator The first jaw in the downbeam secondary collimator (40m away) may be damaged. Copper 250 ˚C 3D ANSYS model, E. Doyle

12. Discussion Items for June 2005 Collaboration Meeting A. IR7 FLUKA Model: 1. Steps to run at SLAC? (Major progress 16 June) 2. Modify for cylindrical secondary collimators? 3. Energy loss distribution with all copper secondaries except TCSM.A6L7 is carbon. B.Distribution of Accidental Hits in IR7? – Ralph C.How much simulation has been done w/ the 60 cm primary collimators? 1. Inefficiency? 2. Hit distribution on all secondaries? 3. Energy distribution in IR7 and arc?