# Presentation: 132829

## CollimationOpening RemarksTom MarkiewiczSLAC

- 19 October 2004

***bnl - fnal- lbnl - slac***

_**US LHC Accelerator Research Program**_

## Meeting Goals

- Institutions involved in LHC Collimation
- CERN, SLAC, FNAL, BNL
- Agreement on how collaborating institutions will work together to the best interests of the LHC
- Who does what, by when?
- Improved methods of communication
- 1-1:  email, phone
- Meetings: phone, video, VRVS, physical
- Progress Reports &/or Statement of Plans
- Informal Discussions with all experts present

## Agenda

## Milestones Since February 2004 LARP Meeting

- CERN
- External review of collimation project, June 2004
- Manufacture, installation and beam test of prototypes
- Improved energy deposition codes & results
- BNL
- Installation of SixTrack / CollTrack package
- Interim Meetings
- May 2004 LARP Collimator Review at BNL
- Phased approach for Phase II
- June 2004 LAPAC at Fermilab
- Blesses project (I think)

## Reminder of the Phase II Issue

- Primary Collimators are 20cm Carbon
- Phase I secondary collimators are 1.0m Carbon
- Survive accident (asynchronous beam abort): eat 8 bunches
- Adequate system inefficiency (11E-4) and impedance for beginning operation
- 7 kW cooling can handle mandated 90kW (1 hr. beam lifetime) load
- Mechanical tolerances maintained during 450 kW (12 min beam lifetime) excursions lasting < 10 sec
- Phase II secondary collimators
- Presumably metal for low impedance
- WILL be damaged in accident, but SLAC’s “rotating” geometry can provide new surface without collimator removal
- Presumably will absorb more of beam
- Is required DC cooling consistent with rotating design and required tolerances?
- How do Phase II secondary collimator parameters affect system inefficiency?
- What is their role as absorbers? Absorber system currently not designed

## Two Possible Approaches Considered

- Engineer “best” collimator consistent with SLAC technology
- Or
- Delay start of engineering until requirements better understood
- Early calculations and MISCONCEPTIONS having to do with fault scenarios led us to choose second path
- Bureaucratic Plan:
- January 2005:	LHC Review in Chamonix
- 			Formal status report to CERN
- ~April 2005:	Go/No-Go Decision for SLAC to prototype this collimator
- If “GO”, hire postdoc & engineer to cement what is currently “donated” services from SLAC ILC group

## SLAC Progress Since February LARP Meeting

- Independent FLUKA analysis of 7 TeV protons in SECONDARY collimator jaws, varying Z and L
- Adoption and benchmarking of CERN FLUKA input file describing IR7
- Basis of June Review
- FLUKA energy deposition studies of SECONDARY collimators for protons lost on PRIMARY 20cm collimator varying Z, L=120cm
- ANSYS studies of MAXIMUM JAW TEMPERATURE & MAXIMUM COOLING WATER TEMPERATURE for specified fault scenarios for Phase II secondary collimators
- 2d at shower max for 90kW, 1 hr. beam lifetime specification
- Time dependent calculations for 10sec. excursions to 450kW, 12min beam lifetimes
- 3d calculations
- Installation and benchmarking of SixTrack and preliminary new results for particle loss and system inefficiency for relevant Phase II configurations

## FLUKA Input File

## Heating of Phase I Graphite Secondary CollimatorsLoss Map#1, 450kW Total Loss Rate, Jaws at 10

- Heating of Phase I Graphite Secondary CollimatorsLoss Map#1, 450kW Total Loss Rate, Jaws at 10

| Total Power | 450 kW |
| --- | --- |
| Power lost in IR7 | 233 kW |
| Power absorbed in beamline elements | 116 kW |

- Engineer Graphite TCS as 7kW device for 90kW DC loss:(7=30/5+margin)
- Handle 30kW for 10 sec as transient

## Heating of 1.2m Cu Secondary Collimators Phase I Carbon design – In-Line with Same Aperture

- 14kW

- 130kW

- 5kW

- 30kW

| TCSH1 (kW) | SLAC | CERN |
| --- | --- | --- |
| Jaws | 111.5 | 116.6 |
| Inox | 7.1 | 7.4 |
| Cu plate | 4.4 | 4.7 |
| Water | 1.1 | 1.1 |
| Total | 124.1 | 129.8 |

- SLAC calculations agrees with CERN’s to 5% for the two cases presented

- Simulation is for 4E11 p/s lost on TCPV

## Initial Design Paradigm

- Replace C Phase I SC with Cu so than Collimation System Efficiency is the identical but Collimation System Impedance is Improved to allow Design Parameters

**11 x 10****-4**

**2 x 10****-4**

**28**

**44**

- AssmannMay ‘04

## SLAC TEAM

- Lew Keller – Energy deposition - FLUKA
- Eric Doyle – Engineering – ANSYS + baseline engineering
- Yunhai Cai – SLAC ARDA – Tracking codes
- Tom Markiewicz – Synthesizer
- Tor Raubenheimer – New ILC Group Leader & Supporter
- Andrei Seryi – Will help with system design tweaks eventually
- Josef Frisch – Will help with conceptual design once problem better defined

## Plans

- Conclusions of current studies will be presented in parallel session on Wednesday and summarized in Thursday plenary session.
- Non-bureaucratic Work Plan for immediate future
- Upgrade FLUKA model to detailed and extensive system developed over last year by CERN & put in use ~ July 2004
- Fix Z, L, system inefficiency and “loss map” via tracking studies at SLAC
- Zero-th order conceptual design for cooling flow and mechanical support backed by ANSYS for heat removal & distortion