US-LHC Activities in AD

1
US-LHC Activities in AD

• Tanaji Sen

2
Overview

• The LHC
• US-LHC Construction Project
• US-LARP Goals and Activities
• Accelerator Physics
• Instrumentation
• Beam Commissioning
• LHC_at_FNAL

The wise speak only of what they know
Gandalf, Lord of the Rings
3
LHC
Control Room
4
Key Parameters
Tevatron LHC
Injection Energy Top Energy Particles/bunch of bunches Trans. Emitt(95) Beam current (p) Stored energy/beam Peak Luminosity 150 GeV 980 GeV 2.7 x 1011 36 20 mm-mrad 0.074 A 1.5 MJ 1.7 x 1032 450 GeV 7000 GeV 1.15 x 1011 2808 22.5 mm-mrad 0.584 A 362 MJ 1 x 1034
5
US-LHC Construction Project

• Interaction Region Quads (FNAL)
• Interaction Region Dipoles (BNL)
• Interaction Region Cryogenic Feedboxes (LBL)
• Interaction Region Absorbers (LBL)
• Accelerator Physics (FNAL, BNL, LBL)
• - related to IR designs and magnets
• - ecloud, noise effects

Last magnets to be delivered in 2006
6
LHC IR Quads at FNAL
FNAL quads
To IP
1st IR quad ready for shipment in May 2004

• FNAL is delivering 18
• IR quads to the LHC
• All IR quads
• (FNAL, KEK) are cryostatted at FNAL
• and shipped from here
• Last quad to be
• shipped in late 2006.

7
FNAL quads installed in IR8
Mission Accomplished ?
Courtesy J. Kerby
8
US- LARP

• Goals stated by J. Strait (2002)
• Extend and improve the performance of the LHC so
  as to maximize its scientific output in support
  of US-CMS and US-ATLAS
• Maintain and develop the US labs capabilities so
  that the US can be the leader in the next
  generation of hadron colliders.
• Serve as a vehicle for US accelerator physicists
  to pursue their research
• Train future generations of accelerator
  physicists.
• It is the next step in international cooperation
  on large accelerators.
• Fermilab has been appointed the Host Laboratory
  to lead this program.

9
US LARP Institutions

• Two main areas
• High field magnets
• Accelerator systems
• Accelerator Physics, Instrumentation,
  Collimation, Commissioning (beam hardware)
• High field magnets BNL, FNAL, LBL
• Accelerator Physics BNL, FNAL, LBL
• Instrumentation BNL, FNAL, LBL, UT Austin
• Collimation SLAC
• Commissioning BNL, FNAL, LBL

10
US-LARP Goals

• Accelerator Physics and Experiments
• - understand performance limitations of current
  IRs and develop new designs
• - Beam dynamics calculations and related
  experiments
• Develop high performance magnets for new higher
  luminosity IRs
• - large-aperture, high gradient quadrupoles
  using Nb3Sn
• - high field beam separation dipoles and strong
  correctors
• Develop advanced beam diagnostics and
  instrumentation
• - luminosity monitor, tune feedback, Schottky
  monitor, rotatable collimators
• - other systems as needed for improving LHC
  performance
• Commissioning
• - participate in the sector test and LHC beam
  commissioning
• - commission hardware delivered by the US

11
IR Upgrade
12
Luminosity and IR upgrade
J. Strait

• An IR upgrade is a straightforward way to
  increase the luminosity by a factor of 2-3
• It must also deal with higher beam currents and
  10 times larger debris power at L1035cm-2s-1
• Several optics design issues
• 50 of LARP effort is in IR magnet design

A luminosity upgrade will be required around
2015 to keep the LHC physics program
productive.
13
Quadrupoles 1st option

• Advantages
• Allows smaller ß, minimizes aberrations.
• Lower accumulation of charged particle debris
  from the IP.
• Operational experience from the first years of
  running.
• Disadvantages
• More parasitic beam-beam interactions.
• Crossing angle has to increase as 1/vß
• IR correction systems act on both beams
  simultaneously

Baseline Design
14
Dipoles 1st 2 options

• Advantages
• Fewer parasitic interactions.
• Correction systems act on single beams.
• No feed-down effects in the quads
• Disadvantages
• Large energy deposition in the
• dipoles.
• Beta functions are larger ?
• increases aberrations.
• Longer RD time for dipoles
• Longer commissioning time
• after the upgrade.

Triplets
Doublets
15
Optics Solutions
ßMax 9 km
Quads first
LARP magnet program aims to build 15T pole tip
fields
ßMax 27 km
ßMax 25 km
Dipoles first triplets
Dipoles first doublets
J. Johnstone, TS
16
IR Design Issues ? Luminosity Reach

• Requirements on magnet fields and apertures
• Optically matched designs at all stages
• Energy deposition
• Beam-beam interactions
• Chromaticity and non-linear correctors, field
  quality
• Dispersion correction
• Susceptibility to noise, misalignment, ground
  motion emittance growth
• Closest approach of magnets to the IP (L)
• Impact of Nb3Sn magnets, e.g flux jumps
• RD time required to develop the most critical
  hardware and to integrate it in the LHC
• .. All need to be considered in defining the
  luminosity reach

17
Towards a Reference Baseline Design

• Proposal by F. Ruggiero (CERN)
• Define a Baseline, i.e. a forward looking
  configuration which we are reasonably confident
  can achieve the required LHC luminosity
  performance and can be used to give an accurate
  cost estimate by mid-end 2006 in a Reference
  Design Report
• Identify Alternative Configurations
• Identify RD to
• - support the baseline
• - develop the alternatives

Separately, the LARP magnet program has been
tasked to deliver a working prototype of a
Nb3Sn quadrupole by 2009.
18
Wire Compensation of beam-beam interactions
19
Long-range interactions

• Long-range beam-beam interactions are expected to
  affect LHC performance based on Tevatron
  observations and LHC simulations
• Wire compensator is proposed to mitigate their
  impact
• RHIC has a 2 ring layout like the LHC can be
  used to test the principle

Difference in kicks between a round beam and a
wire lt 1 beyond 3 sigma
20
Wire compensation in RHIC and LHC
LHC
RHIC
IP
IP6
Reserved for wire compensators
Location of wire compensators Installation in
Summer 2006
To be installed if required to improve performance
. Feasibility would determine upgrade path
21
RHIC beam-beam experiments

• Motivation for experiments Test of wire
  compensation in 2007
• Determine if a single parasitic causes
  beam losses that need to be compensated
• Experiments in 2005 and 2006
• Remote participation at FNAL via logbook
• Motivation for simulations Tests and
  improvements of codes, predictions of
  observations in 2006 and of wire compensation
• Several groups FNAL, SLAC, LBL,
  University of Kansas
• (coordinated at FNAL)
• Website http//www-ap.fnal.gov/tsen/RHIC

22
Beam-beam Experiments and Simulations (2006)
FNAL Simulations

• Beam lifetime responds to vertical separation
  but vertical separation ? 4s (1st study April
  5th, 2006)
• 4 studies in all (April-May) to explore larger
  separations and tune space
• Analysis to find dependence on beam separation
  in progress

• Simulated lifetimes show a linear dependence
  on the beam separation

V. Ranjbar, TS
23
Wire Compensator in RHIC

• 1 unit in each ring
• 2.5m long
• Currents between 3.8 50 A
• Vertically movable over 65mm
• Install in Summer 2006

24
Pulsed Wires

• Required for bunch to bunch compensation PACMAN
  bunches
• Challenges are the high pulse rate and turn to
  turn stability tolerances

LHC bunch pattern
Strength Pulse rate 120 A-m 439 kHz
Turn to turn amplitude stability Turn to turn timing stability 10-4 0.04 nsec
Pulse pattern
Open Design Challenge
25
Energy Deposition
26
Energy deposition

• Primary source of radiation in the IR magnets pp
  collisions, Luminosity
• Tevatron debris power 2 W
• LHC at 1035cm-2s-1, debris power 9kW
• Energy deposition is viewed as the major
  constraint on the IR upgrade
• Could be key in deciding between quads
  first or dipoles first.
• Other sources include operational beam losses
  (e.g. beam gas scattering) and accidental losses
  (e.g. misfiring of abort kickers)

27
Energy Deposition Issues Constraints

• Quench stability? Peak power density
• Require Epeak to be below the quench limit
  by a factor of 3
• Magnet lifetime ? peak radiation dose and
  lifetime limits for various materials
• Baseline LHC expect lifetime 7 years
  for IR magnets
• Upgrade LHC requires new radiation hard
  materials
• Dynamic heat loads ? Power dissipation and
  cryogenic implications
• Require heat load lt 10 W/m
• Residual dose rates ? hands on maintenance
• Require residual dose rates lt 0.1 mSv/hr
• Dedicated system of charged particle and neutral
  absorbers in the IRs

28
Energy Deposition Open Mid-plane Dipole

• ED issues constrain the dipole design to have no
  coils in the mid-plane
• ?peak in SC coils 0.4mW/g, below the quench
  limit
• Estimated lifetime based on displacements per
  atom is 10 years
• Dipole design will require significant RD,
  further LARP design work postponed

R. Gupta (BNL)
N. Mokhov
29
Quadrupole first design

• Without mitigation, Epeak gt 4 mW/g. Target value
  is 1.7mW/g
• Mitigation by thick inner liner
• Stainless steel liners are not adequate
• Thick Tungsten-Rhenium liner reduces
• Epeak 1.2 mW/g

I. Rakhno
30
Tertiary Collimators

• Designed to protect the detector and IR
  components from operational and accidental beam
  losses

Similar collimator used at A48 in the Tevatron
to protect against abort kicker misfire For the
LHC propose 1m long Tungsten or Copper
collimator upstream of neutral absorber
To IP
N. Mokhov
31
LHC Injector
32
LHC Injector in the LHC tunnel

• Injector will accelerate beams from 0.45TeV to
  1.5TeV
• - Field quality of LHC better at 1.5GeV
• - Space charge effects lower, may allow
• higher intensity bunches
• - Could allow easier transition to LHC
  doubler
• The injector will be installed in the LHC tunnel
  during scheduled LHC shutdowns
• Return to the standard SPS injection into the LHC
  will be possible
• The main magnets will be the type of super-ferric
  combined function magnets proposed for the VLHC I.

H. Piekarz (TD)
33
LHC Injector (LER)
Vertical distance between LER and LHC beams is
1.35m

• VLHC low-field magnet
• 0.6 T (injection) ? 1.6 T

34
Beam Transfer
Sequence SPS-gt Injector -gt LHC

• Fast pulsing magnets (PM) have to be turned
  off within 3 micro-secs after LHC is filled.
• CERN Workshop October 2006

--- what is not surrounded by uncertainty cannot
be the truth R.P. Feynman
35
Instrumentation

• Schottky Monitor
• Tune and Chromaticity Feedback
• New Initiatives

36
Schottky Monitor at the Tevatron

• Allows measurements of
• Tunes from peak positions
• Momentum spread from average width
• Beam-beam tune spread of pbars
• Chromaticity from differential width
• Emittance from average band power

37
Schottky Monitor Design

• Schottky Monitor will provide unique
  capabilities
• Only tune measurement during the store
• Bunch-by-bunch measurement of parameters such as
  Tune, Chromaticity
• Average measurements as well
• Momentum spread emittance
• Non invasive Technique
• Diagnosis of beam-beam effects and electron cloud

R. Pasquinelli, A. Jansson
4 Monitors to be installed in the LHC, Summer 2006
38
Tune and Chromaticity feedback

• Goals
• Control the tune during the acceleration ramp to
  avoid beam loss
• Control the chromaticity during the snapback at
  start of ramp
• PLL method excite the beam close to the tune
  and observe the resonant beam transfer function
• Then used in a feedback system to regulate the
  quadrupole current and tune

Measurement in RHIC with tune feedback tune
changes 0.001
39
Tune chromaticity at the Tevatron
Phase Modulation Off

• The Direct Diode Detection method (3D BBQ) from
  CERN implemented in the Tevatron complements
  tune measurements from the Schottky monitors.
  More sensitive than the Schottky.
• This 3D BBQ has been used to measure the
  chromaticity with a method due to D. McGinnis.
• Interest in implementing this method at RHIC and
  the SPS

Phase Modulation On
C.Y. Tan
40
New FNAL Initiatives - proposed

• AC Dipole (A. Jansson)
• Electron lens compensation of head-on
  interactions (V. Shiltsev)
• Crystal collimation (N. Mokhov)
• Measure field fluctuations in magnets (V.
  Shiltsev)

41
Commissioning

• LHC Plans
• LARP involvement
• LHC_at_FNAL

42
LHC Commissioning Plan
Stage I
II
IV
III
No beam
Beam
Beam
I. Pilot physics run First collisions 43
bunches, no crossing angle, no squeeze, moderate
intensities Push performance (156 bunches,
partial squeeze in 1 and 5, push
intensity) Performance limit 1032 cm-2 s-1 (event
pileup) II. 75ns operation Establish
multi-bunch operation, moderate
intensities Relaxed machine parameters (squeeze
and crossing angle) Push squeeze and crossing
angle Performance limit 1033 cm-2 s-1 (event
pileup) III. 25ns operation I Nominal crossing
angle Push squeeze Increase intensity to 50
nominal Performance limit 2 1033 cm-2 s-1 IV.
25ns operation II Push towards nominal performance
R. Bailey (CERN)
43
Beam Instrumentation R.Garoby, R.Jones Beam Instrumentation R.Garoby, R.Jones Beam Instrumentation R.Garoby, R.Jones Beam Instrumentation R.Garoby, R.Jones
Activity Responsible Other CERN LARP
Screens E.Bravin A.Guerrero H.Burkhardt (AP) G.Arduini (AP)
BCT P.Odier D.Belohrad M.Ludwig H.Burkhardt (AP) J.Jowett (AP)
BPM and orbit R.Jones L.Jensen J.Wenninger (OP) W.Herr (AP) I.Papaphilippou (AP)
BLM B.Dehning E.Holzer S.Jackson R.Assmann (AP) H.Burkhardt (AP) B.Jeanneret (AP) S.Gilardoni (AP)
PLL for Q, Q, C R.Jones M.Gasior P.Karlsson S.Fartoukh (AP) O.Berrig (AP) J.Wenninger (OP) X
Profile monitors S.Hutchins J.Koopman A.Guerrero H.Burkhardt (AP) S.Gilardoni (AP) M.Giovannozzi (AP) X
Schottky monitors F.Caspers (RF) R.Jones S.Bart-Pedersen E.Metral (AP) C.Carli (AP) F.Zimmermann (AP) X
Luminosity monitors E.Bravin S.Bart-Pedersen R.Assmann (AP) F.Zimmermann (AP) X
44
Expression of Interest Form
In anticipation of LHC-related studies using the
SPS in the coming months and commissioning next
year, LARP is soliciting interest for involvement
in same. http//larp.fnal.gov/commissioningForm.
html is the link for you to register your
interest in being part of this effort.

• Please respond to Elvin Harms by June 1st

45
SPS studies test LHC issues

• LHC collimator tests
• LSS6 commissioning
• TI8 extraction test
• LSS4/LSS6 interleaved
• LHC beam lifetime
• LHC orbit feedback
• BBLR beam-beam compensation
• LHC BLM tests in the PSB
• --- sample of studies planned
• From G. Arduini (CERN)

46
LARP plans for Beam Commissioning

• Refining areas of involvement, identifying CERN
  counterparts
• 15 people signed up (across all 4 labs)
• LARP presence during SPS run in Summer 06
• 3 FNAL people participating, room for a
  few more
• Sector test presence planned
• About 2 weeks, late 2006 early 2007
• Software effort
• In support of instruments and control
  room here
• Planning for long-term visits during LHC
  commissioning

E. Harms
47
What is LHC_at_FNAL?

• A Place
• That provides access to information in a manner
  that is similar to what is available in control
  rooms at CERN
• Where members of the LHC community can
  participate remotely in CMS and LHC activities
• A Communications Conduit
• Between CERN and members of the LHC community
  located in North America
• LARP use Training before visiting CERN,
  Participating in Machine Studies, Analysis of
  performance, Service after the Sale of US
  deliverables
• An Outreach tool
• Visitors will be able to see current LHC
  activities
• Visitors will be able to see how future
  international projects in particle physics can
  benefit from active participation in projects at
  remote locations.
• Planned Opening in September 2006

E. Gottschalk
48
LHC_at_FNAL
You can observe a lot just by watching
Yogi Berra
49
Control Room at CERN
13 operators on shift experts
Started operation on Feb 1, 2006
50
LHC Challenges

• Machine protection
• Quench protection e.g at 7 TeV, fast losses lt
  0.0005 bunch intensity
• Collimation (400 degrees of freedom!)
• Controlling 2808 bunches
• Snapback and ramp
• ?Q (snapback) 90,
• ?Q (ramp squeeze) 320
• -----

51
Summary of LARP activities

• Optics design of IR upgrade
• Energy deposition calculations in IR magnets
• Design of tertiary collimators
• Beam-beam and wire compensation experiments
• Optics design of a proposed LHC injector
• Design of Schottky Monitor
• Tests of tune and chromaticity tracking
• Proposed new initiatives AC dipole, E-lens,
  Crystal collimation, Field fluctuations
• Participation in SPS and LHC sector tests
• LHC beam commissioning
• LHC_at_FNAL

52
Web pages

• AD larp.fnal.gov
• US-LARP dms.uslarp.org
• LARP document database
• larpdocs.fnal.gov
• FNAL-TD, BNL, LBL, SLAC also have web pages
  links from the uslarp page

E. McCrory
53
Credits

• Accelerator Physics J. Johnstone, N. Mokhov, I.
  Rakhno, V. Ranjbar
• Instrumentation A. Jansson, R. Pasquinelli, V.
  Shiltsev, C.Y. Tan
• Commissioning E. Harms, E. McCrory, J.
  Slaughter, M. Syphers

54
Backups
55
US-LARP activities in 2006

• Accelerator Physics
• FNAL IR design, Beam-beam compensation,
  Energy deposition, tertiary collimators
• BNL Beam-beam compensation
• LBL Electron cloud
• Instrumentation
• FNAL Schottky monitor, tune feedback
• BNL Tune feedback
• LBL Luminosity monitor
• Rotating collimators SLAC
• Magnets
• High field quads FNAL, BNL, LBL
• Commissioning all labs

56
(No Transcript)
57
Features of Doublet Optics

• Symmetric about IP from Q1 to Q3, anti-symmetric
  from Q4 onwards
• Q1, Q2 are identical quads, Q1T is a trim quad
  (125 T/m). L(Q1) L(Q2) 6.6 m
• Q3 to Q6 are at positions different from
  baseline optics
• All gradients under 205 T/m
• At collision, ßx 0.462m, ßy 0.135m, ßeff
  0.25m
• Same separation in units of beam size with a
  smaller crossing angle FE v(ßR/ ßE) FR 0.74
  FR
• Luminosity gain compared to round beams

Including the hourglass factor,
58
LHC Commissioning Plan
From R. Bailey (CERN)
1 Injection and First turn
2 Circulating beam, RF capture
3 450 GeV initial commissioning
4 450 GeV detailed measurements
5 450 GeV 2 beams
6 Nominal cycle
7 Snapback single beam
8 Ramp single beam
9 Single beam at physics energy
10 Two beams to physics energy
11 Physics
12 Commission squeeze
13 Physics partially squeezed
Where are we ? Overall strategy OK Stage I
43 bunches Stage II 75ns Stage III 25ns
low I Stage IV 25ns high I Stage I looked
at Some details behind Need to make this into a
detailed commissioning plan Best developed by the
people who will implement it Machine
coordinators/Commissioners/EICs Accelerator
Systems Work through 2006 (suggest 20 activity)
59
Machine protection

• Metal damage
• 450 GeV 50 nominal bunches
• 7 TeV 7 x 109, about 6 of 1 bunch
• Quench protection
• Fast losses 450 GeV 109, 7TeV 5x105
• During abort 450GeV 1.4x109 p/m in gap
• 7TeV 2x106 p/m in gap
• Collimator damage
• Fast losses 450 GeV 260 bunches
• 7 TeV 4 bunches

60
LHC Sector test with beam
3.3 km of the LHC including one experiment
insertion and a full arc
61
LHC_at_FNAL