Tom Markiewicz

1
Beam DeliveryRD Review

• Tom Markiewicz
• 9 March 2001

2
Talks Prepared for this Committee
Collimation Issues Tor Raubenheimer Final Focus
Issues Andrei Seryi Collimator RD Program
Josef Frisch Vacuum RD Program Leif Eriksson
3
BDIR Mission Statement

• Use requirements of
• Emittance preservation Luminosity stability
• Machine Personnel protection
• Detector background limitations physics
  requirements
• Reliability Cost
• Installation, maintenance, upgrade flexibility
• to develop requirements and tolerances for all
  hardware
• Tunnel Enclosures
• Power Supplies
• Supports
• Magnets
• Vacuum
• Movers
• Shielding
• Collimators
• Dumps
• RF (Crab)
• Instrumentation
• Demonstrate through analysis, simulations,
  example or RD that requirements and tolerance
  are achievable

4
Current BDIR RD Program

• Vibration Suppression
• Understand nature of ground motion its effect
  on the lattice
• Survey /or Measure ground motion
• Seismic
• Cultural
• Develop tolerance criteria and the means of of
  measuring compliance
• Develop means of suppressing effects of GM
• Active
• Passive
• Demonstrate performance of suppression techniques
• Collimation
• Development of rotating consumable collimator
• Development of rotating liquid metal renewable
  collimator
• Wakefield measurement and interpretation
• Material damage RD
• Other
• Vacuum RD Leif
• Magnet RD
• Dump Window RD

5
Active Vibration Suppression RD Status

• Caveats
• Tolerance in each degree of freedom needs to be
  better tabulated
• Choices dependent on QD,QF magnet technology
  choice and detector design
• Optical Anchor
• Position of a lightweight mirror stable to a
  resolution of 0.2nm using a 10m interferometer
  with sealed air-filled arms feedback loop open
• Position of a lightweight mirror controlled
  absolutely, over 1 hour, to lt 1nm by closing
  feedback loop with fringe driving piezo
• New version of above under construction at UBC
• Inertial Sensor
• Conceptual mechanical design of sensor
• Conceptual design of electronics tested shown
  to have adequate noise
• DAQ Feedback algorithm
• Commercial DAQ software tools purchased
• Algorithm development and simulated performance
  in progress
• Intra-bunch Feedback
• Oxford University staff active
• Conceptual design of IP position feedback loop
  and implementation complete
• Bench tests and algorithm efficiency study
  imminent
• Beam tests in planning stage

6
BPM Processor Simulation
7
System Block Diagram
8
BPM Scope
Response at BPM
First 100 ns
Full bunch train
9
Active Vibration Suppression RD Goals

• To a certain extent, 1nm control in one d.o.f.
  has been demonstrated and the rest is merely
  engineering
• The rapid loss of luminosity with offset and the
  smallness of 1nm creates a crisis of confidence
• Reasonable people can disagree at the level of
  demonstration required to believe that this
  problem is adequately under control.
• Solution in principle done
• Non-beam demonstration of the appropriate level
  of relative stability of the appropriate number
  of mechanical magnet equivalents of the
  appropriate masses and sizes, in 3-d,
  incorporating compensation slow drift and sudden
  disturbances Next stage planned
• Beam tests demonstrating luminosity stabilization
  of a real FF under discussion

10
Active Vibration Suppression Plan
Define QD0/QF1 Detector
Develop Optical Anchor
Develop Inertial Sensor
Develop Feedback algorithm
Refine Tolerances
Test on Rigid block
Test on Rigid block
Demonstrate sub 1nm Relative Motion of two long
magnet systems
Demonstrate luminosity stability with sub 1nm
resolution
11
Collimator PrototypeRD Status Accelerator
Physics, BD, Special Projects

• Simulation Experiment
• Lattice
• Required collimation depth
• Collimator load (halo)
• Muon production shielding
• Personnel protection shielding
• Collimator damage thresholds
• Pulse heating
• Single shot damage
• System efficiency
• Wakefield jitter amplification
• Beam measurements
• Analytic estimates simulations
• Proof of principle prototypes see J. Frisch
• Rotating cylindrical wheel
• Liquid Metal Wheel Follower

12
Collimation RD Goals

• To a certain extent, rotating collimator solution
  satisfies lattice tolerances and beam dynamics
  and the rest merely vacuum engineering
• Smallness of apertures, magnitude of beam power,
  fear of unknown halo sources cause discomfort
• Reasonable people can disagree at the level of
  demonstration required to believe that this
  problem is adequately under control.
• Non-beam demonstration of collimator surface
  flatness, aperture control planned
• New ideas to increase collimation depth
  (apertures) and thereby decrease wakefield
  concerns-underway
• Beam tests demonstrating optical solutions to
  halo control in a real FF under discussion

13
Collimator Prototype Plan
Develop Rotating Collimator P.of P.
Develop Liquid collimator P.of P.
Refine lattice understand collimator
Requirements Tolerances
Wakefield Requirements
Tolerance Tests
Technology Choice with refined requirements
Collimator Prototype
Beam Tests of Optical /or Mechanical systems
14
Beam Tests

• Advantages
• Suitability of proposed solution
• Hardware
• Lattice
• Is often in the details of the implementation
• Exact cancellation of high order aberrations
• Coupled or not-considered effects
• Les than ideal input conditions
• Temperature drift
• External noise
• Disadvantages
• Details of SLC, FFTB, Sector-2, etc. may not be
  germane to NLC
• Beam tests ALWAYS take a great deal of effort
• Plans are under study