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Superconducting Undulator R&D Proposal for LCLS-II. Paul Emma (SLAC) Superconducting Undulator R&D Review Jan. 31, 2014. please MUTE your microphones or turn down volume. Outline of Presentation. Meeting Agenda LCLS-II Performance Requirements and Issues - PowerPoint PPT Presentation
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Superconducting Undulator R&D Proposal for LCLS-II
Paul Emma (SLAC)
Superconducting Undulator R&D Review
Jan. 31, 2014
please MUTE your microphones or turn down volume
SCU R&D Review, Jan. 31, 2014
Outline of Presentation
Meeting AgendaLCLS-II Performance Requirements and IssuesSuperconducting Undulators (SCU’s) compared with permanent magnet undulatorsSCU impact on LCLS-II Hard X-Ray (HXR) FEL performanceSCU impact on LCLS-I performance (using Cu linac)Brief SCU R&D Plan (more from other speakers)Review Charge and Committee
This is a review of the R&D Proposal which leads up to a possible design baseline change in 2015, and not an evaluation of that decision.
SCU R&D Review, Jan. 31, 2014
DRAFT Agenda for Jan. 31 Review* (2014)
* Carried out by teleconference to save travel.
Chairman assembles committee response in writing within 2 weeks (Feb. 14, 2014)
Meeting Site at (no password needed):https://portal.slac.stanford.edu/sites/ad_public/reviews/scu_rd_jan_2014/
Review Agenda (all times Pacific/SLAC):07:00 AM (5 min) Welcome and Charge Norbert Holtkamp (SLAC)07:05 AM (30 min) SCU Advantages in LCLS-II Paul Emma (SLAC)07:35 AM (20 min) Undulator Tolerance Estimates Heinz-Dieter Nuhn (SLAC)07:55 AM (50 min) SCU Development at ANL Efim Gluskin (ANL)08:45 AM (10 min) (break) -08:55 AM (50 min) SCU Development at LBNL Soren Prestemon (LBNL)09:45 AM (20 min) SCU Field Measurements Diego Arbelaez (LBNL)10:05 AM (25 min) (executive session) Committee Only10:30 AM (adjourn) -
SCU R&D Review, Jan. 31, 2014
LCLS-II Design SummaryNew 4-GeV CW linac (1 MHz) and 2 new FELs (~2020)2 New Permanent Magnet (PM) adjustable gap undulators
SXR FEL: 0.2 - 1.3 keV (SASE and self-seeded)HXR FEL: 1.2 - 5.0 keV (SASE and self-seeded?)
PM for HXR undulator barely allows 5.0 keV in SASE (no self-seeding unless 4 keV or less) – existing und. hall is 150 mWill also replace existing LCLS-I und. with adj.-gap PMU (HXR)Radiation damage to PM’s is a major issue at 1 MHz (gap?)HXR FEL based on 150-m long PM-undulator at 4 GeV is very sensitive to e- emittance when tuned above 3.5 keV (risk)
Schematic of the LCLS-II facility with the new SCRF linac and two new undulators, along with the existing copper (Cu) linac, undulator and experimental halls. The “Cu Linac” is in the 3 rd km of the SLAC tunnel.
HXR FELSXR FEL
SCU R&D Review, Jan. 31, 2014
Superconducting Undulator Motivation
Using an SCU for the LCLS-II HXR undulator……allows full LCLS-II performance to 5 keV (SASE & self-seeded) and with 50-70 m less undulator (or more taper)…has orders of mag. less sensitivity to rad. dose…is much less sensitive to e- emittance (new high-rate gun)…produces very low pressure in a small vacuum chamber (gas scattering at 1 MHz)…enhances LCLS-I FEL power, whereas a new PM degrades it.
SCU R&D Review, Jan. 31, 2014
SCU’s Provide Real Performance Enhancement
SCU (Nb3Sn)
SCU (NbTi)
PM (NdFeB)
PM (in-vac)
gap = 7.5 mm (5.7 mm for in-vac same stay-clear)
Much higher fields for a given period and gap(planar undulators)
LCLS-II PMUlu = 26 mmBpk = 1.0 Tgap = 7.2 mm
SCU R&D Review, Jan. 31, 2014
Examine Field’s Impact on LCLS-II Undulator Length
The next 2 slides assume the following:4-GeV electron energy (1 kA, ge = 0.45 mm, sE = 500 keV, etc.)1.2 - 4.0 keV photon tuning range (SASE & self-seeded)Full-height magnetic gap of 7.5 mm (chamber gap is 5.7 mm)Und. period set by lower-limit photon energy (1.2 keV) for FEL resonance at highest field possible for this gap and technologyUnd. length set by max. photon energy (4 keV), assuming 18LG (based on beam brightness), plus 50% longer for self-seedingCompare in-vacuum and out-of-vacuum Permanent Magnets (NdFeB), and SCUs (NbTi & Nb3Sn) – all with same chamber gapUnd. length includes 1.15-m breaks, 3.4-m segments, +20% for margin, and 4-m extra space for self-seeding monochromatorExamine total length sensitivity to main parameters (see next)…
SCU R&D Review, Jan. 31, 2014
Undulator Length vs. e- Energy for LCLS-II HXR
PM
In-VacNbTiNb3 Sn
lu = 27.5 mm, 24.8 mm, 20.3 mm, 18.7 mm (4 GeV)
1.2 - 4.0 keVSelf-Seeded (SS)
l u =
16.
3 m
m
l u =
20.
3 m
m
l u =
18.
7 m
m
g = 7.5 mmge = 0.45 mmIpk = 1 kAsE = 500 keVb = 15 m
Period varies with energy to maintain lower-limit tuning range (1.2 keV)
SCU R&D Review, Jan. 31, 2014
Und. Length Comparison for LCLS-II HXR
Self-Seeded + 20%
PMIn-VacNbTiNb3 Sn
lu = 27.5 mm, 24.8 mm, 20.3 mm, 18.7 mm
PM sensitive to gex,y
5 keV SS not possible
stay-clear = 5.7 mm
a b c
d e f
m-bunching not incl. lu defined by this
SCU R&D Review, Jan. 31, 2014
Compare Baseline LCLS-II with LCLS-I (Cu linac)
PM, lu = 26 mm (project baseline)LCLS-I
LCLS-I FEL Performance Compromised with new PMU
H.-D. Nuhn
SCU R&D Review, Jan. 31, 2014
Compare Nb3Sn (lu = 20 mm) LCLS-II with LCLS-I
Nb3Sn, lu = 20 mm
LCLS-I FEL Further Enhanced with 20-mm SCU
H.-D. Nuhn
SCU R&D Review, Jan. 31, 2014
SCU R&D Plan in Brief
ANL…Builds 2-m test cryostat (based on existing design at APS)Build & test 1.5-m long NbTi prototype planar undulator (lu 21.0 mm)
LBNL…Build & test 1.5-m long Nb3Sn prototype planar undulator (lu 18.5 mm)Develop and tune each of the NbTi and Nb3Sn undulators
Both Labs…Develop field measurement and field correction techniquesDemonstrate predicted field, field quality, end-field corrections, field measurement and tuning, cold mass fiducialization, and integration of cold mass into cryostat
Goal: Within 18 months deliver 2 fully functional, 1.5-m long, SC prototype undulators which meet LCLS-II specifications
SCU R&D Review, Jan. 31, 2014
SCU R&D and LCLS-II Construction Time-Line
17-Month SCU R&D (to ~May 2015)3-Year production cycle for 33 SCU segments (~3 m/ea)Installation of LCLS-II undulator starts mid-2018
Start SCUR&D
2014 2015 2016 2017 2018 2019 2020
End R&D Start Und.Installation
Start Und.Production
UndulatorProductio
nSCU R&D
Linac and Cryo Install
Complete
SCU R&D Review, Jan. 31, 2014
Review Committee and Charge
Name Institute E-Mail Address ConfirmedMikael Eriksson, chair Max Lab [email protected] Yes – 12/18/13Sara Casalbuoni ANKA [email protected] Yes – 12/18/13David Larbalestier FSU [email protected] Yes – 12/17/13Joachim Pflueger EXFEL [email protected] Yes – 12/18/13Johannes Bahrdt HZB [email protected] Yes – 01/08/14
Review Committee:
Charge to the Committee:1. Is the SCU R&D plan technically sound, and is it well enough defined in scope,
schedule, and cost so as to produce definitive results that can support a baseline design change to the hard x-ray LCLS-II undulator, by May 2015?
2. If the plan appears insufficient, what recommendations can the committee make to improve the chances for supporting a baseline change within 18 months?
3. What further alterations might be made to solidify the plan and move it forward in time or reduce costs?
SCU R&D Review, Jan. 31, 2014
End
SCU R&D Review, Jan. 31, 2014
Compare Nb3Sn (lu = 18.5 mm) LCLS-II with LCLS-I
Nb3Sn, lu = 18.5 mmLCLS-I
LCLS-I FEL Performance Enhanced with New SCU
H.-D. Nuhn
SCU R&D Review, Jan. 31, 2014
Und. Length with 4-mm Stay Clear (5.8 mm gap)
PMIn-VacNbTiNb3 Sn
lu = 25.0 mm, 22.0 mm, 18.6 mm, 17.0 mm
stay-clear = 4.0 mm
SCU R&D Review, Jan. 31, 2014
Prototype Undulator Parameters
