nlc - the next linear collider project sheppard/pitthan july 14, 2015 power meeting june 8=9,2002...
Post on 22-Dec-2015
215 views
TRANSCRIPT
NLC - The Next Linear Collider Project
Sheppard/Pitthan April 19, 2023
POWER MeetingPOWER MeetingJune 8=9,2002June 8=9,2002
Durham, EnglandDurham, England
IP Beam Instrumentation, SLAC Wednesday June 26, 2002
R. Pitthan and J. Sheppard
Sheppard/PitthanApril 19, 20232
NLC - The Next Linear Collider Project
First Meeting: June 8-9, 2000
Ushaw College, Durham, England
Sponsored by: Institute of Particle Physics Phenomenology (IPPP), Unversity of Durham (UK)
Organized by: Gudrit Moortgat-Pick, DESY
http://www.desy.de/~gudrid/power.html
Sheppard/PitthanApril 19, 20239
NLC - The Next Linear Collider Project
• Collection of theorists, experimentalists, accelerator folks
• Did not discuss electron polarization; it’s in the bag
• Positron polarization looks feasible in the range of 40%-70% polarization
• Daresbury to prototype TESLA helical undulator, 3 year time frame, funding limited
•TESLA having difficulty developing a scheme for post-collision polarimetry (Schuler)
•Polarized positron demonstration at FFTB needs polarimetry
•See http://www.desy.de/~gudrid/power.html for talks
Interesting Points
Sheppard/PitthanApril 19, 202310
NLC - The Next Linear Collider Project
Contacts
Roger Carr, SSRL
Max Cornacchia, SSRL
Ralph Nelson, SLAC RP
Roman Tatchyn, SSRL
Helmut Wiedemann, SSRL
Klaus Flöttmann, DESY
Alexander Mikhailichenko, Cornell
Yuri Batygin, SLAC NLC
Vinod Bharadwaj, SLAC LCLS/NLC
Artem Kulikov, SLAC PEPII
David Schultz, SLAC NLC
Maria Caturla, LLNL
Werner Stein, LLNL
Sheppard/PitthanApril 19, 202312
NLC - The Next Linear Collider Project
• Put development of NLC conventional e+ source on hold
• Use resources to investigate the feasibility of a polarized positron source for the NLC
• Look into the use of a K1 helical undulator and 150 GeV NLC primary electron beam for polarized positron production
• Because of drawback of coupling e+ production to primary e-, investigate other options:
•back scattered laser (Compton)
•short-period novel undulator on dedicated beam
Change in Direction of NLC Positron Effort
Sheppard/PitthanApril 19, 202313
NLC - The Next Linear Collider Project
NLC Polarized Positron System Layout
Sheppard/PitthanApril 19, 202314
NLC - The Next Linear Collider Project
NLC Polarized Positron Target Station Layout
Sheppard/PitthanApril 19, 202315
NLC - The Next Linear Collider Project
Codes: MatLab files, EGS4-Pol, BeamPath
Undulator: K1, u = 1.4-0.7 cm, helical
Search for Optimization: Eb, u, K, target material and thickness, collection scheme
Photon Beam Specification
Target Studies: Ti-alloy: hydro and radiation damage study launched at LLNL
Effect on primary electron beam, studies begun; commissioning and operating scenarios
Open also to Compton based photon sources (lasers and FELs)
What’s Going On? What’s the Status?
Sheppard/PitthanApril 19, 202316
NLC - The Next Linear Collider Project
We had a discussion at LC02 to explore the possibilities of using a microundulator and the damped, 50 GeV SLAC beam in the FFTB to study positron production. Expectedly warm response from all e+ folks
Use of a Microundulator to Study Positron Production
Sheppard/PitthanApril 19, 202317
NLC - The Next Linear Collider Project
Use the SLAC 50 GeV, low emittance beam in conjunction with a 1-2 mm period helical undulator to demonstrate undulator based production of polarized positrons for linear collidersMeasure the yield, spectrum, and polarization of both the photons and positrons
An Immodest Proposal
Do this in the next 22-42(?) months in the FFTB enclosure:•Proof of Principle Demonstration•Validate Codes•Develop Spin Diagnostics•Develop e+ Spin Diagnostics
•Maybe Get a Surprise (better not)
Sheppard/PitthanApril 19, 202318
NLC - The Next Linear Collider Project
What’s the Big Idea?
Goals:Goals: • demonstrate the viability of undulator based positron
production, both polarized and unpolarized • measure the yield, spectrum, and polarization
gammas and positrons.• design (steal, borrow) conversion, collection, and
detection systems• validate the microundulator-photon production codes
Many opportunities for collaboration amongst collider laboratories, and including experimenters from both the colliding physics and the fixed target physics communities who are experts in polarimetry. Efforts for the development of such a collaboration underway.
Sheppard/PitthanApril 19, 202319
NLC - The Next Linear Collider Project
FFTB Beams
Size <50 m to thread through a narrow sub-mm-gap undulator
• Divergence < 1/
Critical parameters in red
Sheppard/PitthanApril 19, 202320
NLC - The Next Linear Collider Project
Positron Polarization as a Function of Positron Energy
Sheppard/PitthanApril 19, 202321
NLC - The Next Linear Collider Project
Positron Polarization as a Function of Positron Energy
Sheppard/PitthanApril 19, 202322
NLC - The Next Linear Collider Project
Positron Spectra for Different Ti Target Lengths
Sheppard/PitthanApril 19, 202323
NLC - The Next Linear Collider Project
Positron Polarization for Different Ti Lengths
Sheppard/PitthanApril 19, 202324
NLC - The Next Linear Collider Project
Positron Polarization for Different Ti Lengths
Sheppard/PitthanApril 19, 202325
NLC - The Next Linear Collider Project
What Does the Hardware Look Like?
Sheppard/PitthanApril 19, 202326
NLC - The Next Linear Collider Project
A fully modeled experiment which simulates results and identifies hardware
requirements
• Beam line design to determine accelerator hardware specifications
• Cost and schedule development
• Acceptance of proposal and release of funds
• Construction, Installation, Checkout, and Commissioning
• Do experiment and compare with simulations
What is Required
Sheppard/PitthanApril 19, 202327
NLC - The Next Linear Collider Project
2.4 mm 0 SC, bifilar helical undulator prototype: A. Mikhailichenko
Cornell Univ., 5/21/02
Sheppard/PitthanApril 19, 202328
NLC - The Next Linear Collider Project
2.4 mm 0 SC, bifilar helical undulator prototype: A. Mikhailichenko
Cornell Univ., 5/21/02
Sheppard/PitthanApril 19, 202329
NLC - The Next Linear Collider Project
2.4 mm 0 Pulsed Cu helical undulator prototype: A. Mikhailichenko
Cornell Univ., 5/29/02
Sheppard/PitthanApril 19, 202330
NLC - The Next Linear Collider Project
Experimental Anchor Point Needed
•Since there is no experimental data on polarization (or loss) in scattering, propose a Testbeam Experiment in Sector 0 (the “Ladder” Experiment): Scatter the SLAC polarized electron e-
beams by different r.l. Ti targets, measure relative polarization in the E-158 Møller Spectrometer. Projected relative accuracy 1% (Chudakov).
Sheppard/PitthanApril 19, 202331
NLC - The Next Linear Collider Project
EPOLEGS4: Polarized e- thru Different Targets
Sheppard/PitthanApril 19, 202332
NLC - The Next Linear Collider Project
EPOLEGS4: Polarized e- thru Different Targets
Sheppard/PitthanApril 19, 202333
NLC - The Next Linear Collider Project
EPOLEGS4: Polarized e- thru Different Targets
Sheppard/PitthanApril 19, 202334
NLC - The Next Linear Collider Project
•Looking for help of all types in all areas
• Need viable polarimetry for demonstration
• Proposal by Summer’s End (2002)
• Thoughts on Depolarization via ionization loss? (Multiple scatter does not look to be a problem)
• Is electron experiment useful?
• Is demonstration required?
What’s Going On?