july 7, 2008slac annual program reviewpage 1/23 lhc accelerator research at slac t. markiewicz slac...

July 7, 2008 SLAC Annual Program Review /23

LHC Accelerator Research at SLAC

T. Markiewicz

SLAC Department Head (9/2008)LARP Accelerator Systems Division Leader (9/2008)

LARP Collimation Leader (9/2005)LARP Rotatable Collimator Manager (9/2004)


LARPLHC Accelerator Research Program

Mission Statement:– Make more LHC luminosity earlier– Use, develop and preserve unique US resources and

capabilities in accelerator science and technology

BNL - FNAL- LBNL - SLAC

Accelerator Systems– Instrumentation– Collimation– Accelerator Physics

Nb3Sn Magnet Systems

Program Management– Beam and Hardware

Commissioning– Long Term Visitors to CERN– Toohig Fellowships

Actual or Planned LARP Budget (M$)

0

2

4

6

8

10

12

14

2004 2005 2006 2007 2008 2009 2010 2011 2012

Fiscal Year


History of SLAC as member of LARP

FY 2003 Jim Strait talk at “SLAC Futures” series mentions challenges in LHC collimation. Discussions with CERN & LARP lead to invitation to join LARP to adapt NLC “rotatable collimator” to LHC

LARP Funding

FY 2004 Introduction to LHC collimation project;

Begin design studies: FLUKA, ANSYS, SixTrack

110k$

FY 2005 Continue studies, agree on performance specs with CERN, write Conceptual Design Report of a Phase II collimator

190k$

FY 2006 Design Review; hire ME & CAD; re-design and begin to fab small prototypes & set up test lab

350k$

FY 2007 Collimator Engineering (hire postdoc)Beam-Beam simulation effort in ACD beginsChao-Phinney-Wienands coordinate beam commissioning requestsProgram Management + LARP travel

800k$+ 30k$+ 18k$+ 50k$=898k$

FY 2008 Collimator Engineering Beam-Beam simulation effort in ACD for Electron Lens & WiresBeam Commissioning travel for LLRF, SPS e-cloud, Beam Inst.New Initiatives: CRYSTAL Collimation & Crab Cavity Program Management + LARP travel

950k$+ 80k$+ 40k$+95k$+ 240k$=1405k$


LHC AR at SLAC begins FY 2008

LHC AR at SLAC Advisory Committee

* Alex Chao* TWM* Nan Phinney* Tor Raubenheimer* Uli Wienands


LHC Accelerator Research at SLAC Department Concept

Participate in the LHC accelerator physics program:– by contributing in areas where SLAC has expertise & experience– enhance SLAC’s areas of core excellence:

• collective effects, RF cavity design, collimation systems,…

– educate SLAC staff on HEP’s only energy frontier machine– develop contact with next generation of accelerator physicists

Use US LARP to coordinate & validate R&D plans and performance– NOT independent bi-lateral SLAC/CERN planning

Use US LARP funding when possible, especially to leverage SLAC labor through M&S & Travel

Use SLAC ARD funds as available for programs LARP cannot fund– ARD plan calls for ~8 FTEs for last half of FY08


LHC-AR Tasks & People Funded by LARP in FY08

Rotatable Collimators Gene Anzalone (MFD)Eric Doyle (LHC-AR)Lew Keller (ret.) Steve Lundgren (LHC-AR) Tom Markiewicz (LHC-AR) Jeff Smith (LHC-AR)

Simulation of beam-beam effects in support of Wire & Electron Lens compensation schemes

A. Kabel (ACD)


SLAC # People ProjectLHC LLRF John Fox , Claudio Rivetta, Themis

Mastorides, Dan van WinkleAdapt PEP-II LLRF Tools to LHC & Use for System Configuration, Study & Improvement

SPS RF Feedback to control Ecloud

John Fox, Jiajing Xu Studies of Transverse RF to control Electron Cloud Instabilities in the SPS

SPS Vacuum Ch tocontrol Ecloud

Mauro Pivi, Lanfa Wang Ecloud Remediation via Grooved & Coated Vacuum Chambers

LHC Beam Commissioning

Alan Fisher LHC Instrumentation Commissioning

LHC Crab Cavity Andrei Seryi, Cho Ng, Zenghai Li, Liling Xiao

Crab Cavity Studies

Crystal Collimation Andrei Seryi, Tom Markiewicz, Shilun Pei, Jeff Smith, Gennady Stupakov, Bob Noble

Crystal Collimation experiments at SPS and Tevatron with extension to e-,e+ tests at SLAC

PS2 Studies Uli Wienands Develop US Plan to participate in CERN White Paper for PS2 design

LHC AR Tasks Proposed to LARP in FY08 & Accepted in LARP FY09 PlanFY08 Travel Funded by LARPFY08 Labor Funded by SLAC

LARP budget allocation in FY09 still TBD!!


SLAC Concept for LHC Phase II Secondary CollimatorsImprove LHC Impedance and Collimation Efficiency

beambeam

• beam spacing: geometrical constraint

• Length available 1.47 m flange - flange

• Jaw translation mechanism and collimator support base: LHC Phase I

• 12 kW per jaw Steady State heat dissipation

Cu coolant supply tubes twist to allow jaw rotation

Hub area

Glidcop Cu Mo

Cantilever Mo shaft @ both ends

Helical cooling channels

25mm below surface

20 facets


Cu Jaw-Cu Hub-Mo Shaft Design

2mm shaft-jaw gap gives x5 improvement in thermal deformation over solid shaft-jaw design1260 um 236 um (60kW/jaw, 12min) 426 um 84 um (12kW/jaw, =60min)

Rather than Cu, Moly shaft improvesGravity sag x3: 200 um 67 umThermal bulge 30%: 339 um 236 um

Molybdenum Shaft

Copper Mandrel

Copper tubing wound in groove

Molybdenum Shaft

Copper Mandrel

Copper tubing wound in groove


Status of RC Program

1. Jaw support & rotation mechanism COMPLETE (June 2007)2. First full single jaw-hub-shaft unit COMPLETE3. Preliminary tests indicate performance in accord with FEA to ~10%

Final Jaw Braze 22 April 2008

Test Stand with External Heaters


RC Program Plans

FY2008-FY2009 Plan: Complete RC1:• Finalize RF design• Test a few new concepts to simplify machining & brazing process• Order parts for 2-3 new jaws: copper mandrels, Mo shafts, Glidcop® jaws• Fab & braze 2-jaws, 4-supports, RF features in new vacuum tank• Metrology & vacuum tests• Mechanical motion tests on existing CERN system

Ship to CERN in late 2009 for • SPS Transfer Line Robustness Test• LHC Beam Dynamics Test

FY2010 and beyondIf production decision made, provide engineering & commissioning support


Beam-Beam SimulationsAndreas Kabel (ACD)

Goal– Benchmark beam-beam simulations codes with RHIC experimental

data and evaluate the LHC beam-beam performance with long-range and head-on beam-beam compensation

PLIBB code– PIC code, with MAD-X lattice input & Intra-beam scattering– for RHIC wire experiments and Electron lens

Example: Beam Transfer Function for RHIC wire compensator vs. simulation


LHC LLRFJohn Fox , Claudio Rivetta, Themis Mastorides, Dan van Winkle

Why SLAC?– PEP-II and LHC have same basic LLRF architecture– SLAC Group has much unique expertise and well developed set of software tools

developed for PEP-II that can be used to configure the LHC system, study it and improve it

Progress in 2008– Three multi-weeks trips in April, June 2008– SLAC software model configured for LHC and interfaced to control system

Near Term Plans– 4 more person-weeks at CERN in FY08 for beam commissioning

• Data from closed loop LLRF system with beam present will be compared against model and changes to LHC hardware configuration suggested

– Expand model to include feedback & longitudinal emittance dilution– Eventually, develop theory & programs to model the long-term (24 hr) behavior


Sample LLRF Result

Open Loop Xfer Function from time-domain excitation technique vs. model result (green)


Transverse RF Feedback in SPS to Control Beam Instabilities Produced by Electron Cloud Effects

John Fox, Jiajing Xu with LBL&CERN

SPS Ecloud dynamics studies predict– Horizontal - coupled-bunch behavior

– Vertical - single bunch-like instability

2008 Plan– Measure & quantify Ecloud effects on beam (instrumentation)

– Compare measurements with E cloud/beam models

≥2009 Plan– Develop beam-FB simulation, evaluate possible feedback implementations.

– Propose a technical implementation & develop Engineering Specs

– Proof of principle experiments & technical R&D

Eventual possible LHC construction project item


Transverse RF Feedback Measurements & HW

Measurements of x-y bunch structure in SPS will be made in August. •Initial measurements taken parasitically in June show a high frequency structure on the beam, but have instrumental issues

Example of existing bunch-by-bunch FB (PEP-II, KEKB,..)SPS and LHC needs may drive new processing schemes and architectures


Experimentation to Investigate Possible Use of Crystals as High Efficiency Primary Collimators

Andrei Seryi, Tom Markiewicz , Bob Noble, Shilun Pei, Jeff Smith, Gennady Stupakov

Why SLAC:– Traditional expertise in collimation optics & devices for accelerators with

high power density beams

Where:– T980 at FNAL Tevatron - now through 2010(?)– CRYSTAL at the SPS – now through 2009– Possible future e+/e- experiments at SLAC NLCTA and FACET

Collaborators• RD22 team from CERN-Italy-Russia (1990-2007 SPS & H8 extracted line)• Fermilab team (1993-98, 2005-2007 Tevatron)• BNL Team (2005 RHIC)

Status & Plans• Engineering plan for contributing “Roman Pot”• Data analysis & interpretation• Application to electrons and possible production of photon beams


Grooved Vacuum Insertion Test at the SPS for Electron Cloud StudiesMauro Pivi, Lanfa Wang with LBL&CERN

Electron cloud mitigation test chambers for SPS in prep– SLAC is manufacturing two grooved insertions

• Metal folding & razor blades techniques for 1mm max. height

– Installation Testing planned in summer 2008

Metal Folding: Form multiple folds. [EMEGA Company, USA] Brazed-up Assembly: Use individual razor type foil blades


LHC Crab CavityAndrei Seryi, Cho Ng, Zenghai Li, Liling Xiao

Crab Cavities for each beam and each IP are needed for any luminosity upgrade requiring a larger crossing angle

SLAC ILC Crab Cavity design experience and ACD computational tools immediately applicable

Crab Cavity collaboration of all LARP labs, CERN and others (KEK, RAL, JLAB,…)

SLAC responsibilities in areas of:– RF modeling of cavity & coupler design– HOM damping & Multipacting Studies – Thermal & Mechanical studies with TEM3P code and and

ANSYS cross-check:– Crab and collimation – Overall coordination


CERN PS2 (replacement for PS) studiesUli Wienands et al

* Scope and budget are under discussion* Synergies with the FNAL MI upgrade* Interest from all 4 LARP labs

3 possible packages1. Intensity effects, instabilities

2. RF system

3. Tracking, nonlinearities, space charge, halos, H- injection

LARP+LAUC DOE Review – 19-20 June 2008 LARP Accelerator Physics - W. FischerSlide n° 22


Summary

SLAC initially got involved with LHC accelerator research through LARP as a by-product of its Linear Collider collimator R&D

SLAC expertise and experience is highly relevant in many other areas and effort is sought after by LARP and by CERN

These expanded activities are just beginning, with good early results, supported both by LARP and by SLAC

SLAC is prepared to participate in a US “LHC Luminosity Upgrade Project” & is participating in ongoing scope and schedule discussions

july 7, 2008slac annual program reviewpage 1/23 lhc accelerator research at slac t. markiewicz slac...

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