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. KellerLHC Collab. Mtg., 15-17 June, 2005

Beam 1

Beam 2

Primary collimators

First group ofsecondarycollimators

40 m

dipoles

IR-7

Z (cm)

X (

cm)

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

Carbon

Axial Position of Halo Interaction Point vs. Distance from Primary Collimator Edge

Why a sharp peak ≈ 1µfrom the edge?

Beam

Jaw edge

Energy Spectra of Particles Hitting TCSH1

Keller: 2004-10-06

All Particles-7

Spatial Distribution of Particles from TCPV at face of TCSH1 when Jaws at 7 sigma

Upper right jawLower left jaw

Concentrating E_dep in the Front Part of the Jaws

(Use CERN-provided ray files)

COPPERkW Deposited in TCSH1 upper right jaw vs. length

-1.00

1.00

3.00

5.00

7.00

9.00

11.00

0 20 40 60 80 100 120

Z (cm)

kW/5

cm

77% on TCPV, 6.7% on TCSH1, 77 kW

77% 0n TCPH, 1.5% on TCSH1, 58 kW

77% on TCPS, 6.0% on TCSH1, 92 kW

77% on TCPV, 6.7% on TCSH1, 70 kW, Carbonpre-radiator

CARBON-TUNGSTENkW Deposited in TCSH1 upper right jaw vs. length

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

0 4 8 12 16 20 24 28 32 36 40 44 48

Z (cm)

kW

/2 c

m

on TCPV, 6.7% on TCSH1, 61 kW 77%

Carbon pre-radiator

Tungsten with carbon pre-radiator

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.

2.5 cm

Missteered beam (9E11 protons)on secondary Jaw

What is the damage area in a missteering accident?

CopperJaw

Cross section at shower max.

Copper

Fracture temp. of copper is about 200 deg C

3D ANSYS model, E. Doyle

Accident Case – jaw adjacent tothe one being directly hit, ≈ 4 mm gap.

This jaw may be damaged too.

840 deg C

Fracture at 200deg C

Copper

Copper

3D ANSYS model, E. Doyle

Another accident Case – Beam hitsthe horizontal primary collimator

The first jaw in the downbeam secondarycollimator (40m away) may be damaged.

Copper

Copper

250 ˚C

3D ANSYS model, E. Doyle

Discussion Items for June 2005 Collaboration Discussion Items for June 2005 Collaboration MeetingMeeting

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?