Status of Cornell s ERL Project

Transcription

1 1 Status of Cornell s ERL Project Georg Hoffstaetter, Professor Cornell University / / SRF group & ERL effort a) Vision for the Future b) Developments since ERL workshop at Cornell in June 2009 c) Planned activities Design Research Education Georg H. Hoffstaetter Future Ligh Sources Workshop Status of Cornell s ERL 1 March 2010

2 2 Layout and Optics since ERL workshop 1) Quality engineering:(a) shorter building to not cross road, 14 undulators (b) No third, and reduced 2 nd floor on x-ray user building (c) Tighter and shorter Turn Around 2) Analysis of one versus 2 turn ERLs 3) Decision to build a 1 turn ERL to reduce operational risks 1) Keep CESR as is. Later upgrade reduces North emittance by 50% 2) Provide a limited number of novel experiments: 14 x-ray beamlines 3) Complete layout, magnet lattice, optics: version 8.0

3 3 Electron Beam Parameters 1) Hard x-rays: 5GeV, competitive current: up to 100mA low charge per bunch low emittance 2) Working modes: current, emittances, energy spread, bunch length A) 100mA, 30/30pm, 2.e-4, 2ps B) 25mA, 8/ 8pm, 2.e-4, 2ps C) 25mA, 300/10pm, 2.e-3, 1ps in South, 100fs in North beamlines 300pm 24% 12% 100fs 0-12% Energy spread at beam stop D) The option of large bunch charge (1nC) with low repetition rate (100kHz), without energy recovery, is not used for x-ray users. up to 1nC is used for accelerator studies, e.g. of XFELO or HGHG FELs

4 4 Lattice choices for Version 8.0 Accelerator R&D area Completely reworked model TA and TB have a smaller bending radius (40m), with mergers. 0.5mrad soft bends to protect undulators A diagnostic beamline (DB) is added All bending magnet lengths adjusted for single power supplies. Collimators have been added prior to all undulators Beam abort collimators have been added prior to LB and LA. BPMs and Corrector Coils have been added everywhere in SA, TA, TB, and NA. Vacuum pump ports, sliding joints, and gate valves have been added everywhere.

5 5 Layout and Optics: Major Sections 1) Second Injector A 30cm kicker has been placed prior to merger bends Cutesy Chris Mayes 2) TA & TB with demerger and merger Complete 3) Isochronous NA undulator cells A reverse bend has been added to these cells 4) Dump Added 5) Path length adjuster in TB

6 6 Layout and Optics: Devices 6) Vacuum system Pump Ports, Sliding Joints, and Gate Valves have been added (YL & DR) 7) Orbit Correction BPMs and Correction coils have been placed everywhere 8) Collimators Collimators are placed prior to every undulator, and beam abort collimators have been added 9) Dispersion compensation bends at merger an dump Second pass merger dispersion is matched to zero from the last NA cell 10) X-ray absorbers to protect cavities Collimators already shield all SR prior to cavities (NA end and TA end)

7 7 Layout and Optics: Miscellaneous 11) Spurs in AutoLISP Valeri has modified the AutoCAD generation program to be more general 12) Optimize Optics Mode A (on-crest) is complete Mode C (bunch compression) is in progress (CE dispersion and time of flight are difficult to adjust) 13) Adjust magnetic fields for SR losses Need to get Bmad to calculate. However, Relative energy change due to SR is ~ ) Efficient Distribution of Power supplies DR classified and adjusted bend lengths. These have been added to the lattice

8 8 Layout and Optics: Turnaround murgers 1.5 m 0.6 T 1.0 m 0.3 T 3.0 m 0.57 T, 0.31T

9 9 Layout and Optics: Undulators NA SA Provides 14 high spectral brightness beamlines

10 10 Electron Beamline Elements A Huge job industry connections have to start now From a recent RFP for the electron transport system: Furthermore the SRF linac: 64 cryomodules 384 cavities with 7 cells 385 RF sources, couplers, etc 64 superconducting quadrupoles 128 superconducting correctors 64 cold bpms

11 11 Conventional Construction 1) The engineering firm ARUP is producing a baseline for X-ray buildings, new office space, 14ft diameter tunnel, either ebtbm or mining. 2) UTAP is a consultant on tunneling, will review ARUP in February. ARUP UTAP

12 12 Conceptual ERL design x x inj acc acc

13 13 Significant IBS and Touschek loss challenges 1) Low emittances create very large beam density and therefore large IBS and Touschek rates leading to emittance and energy spread growth. 2) The relevant beam density is the slice density, not the rms density. 3) Small round emittances allow round, narrow undulator apertures. The IBS Halo then has to be collimated accordingly, inceasing Touschek loss rates. 4) Cornell ERL has large collimators in the tunnel to eliminate loss rates from the arcs, and smaller collimators in front of every undultor.

14 14 Localization and elimination of nonlinear errors Distortions of a regular grid of beamlets After cryomodule Before cryomodule

15 15 Nonlinear Field Error in the 2-3 region Localized by a beam based search 0.20 Center of 3 rd HOM absorber 0.15 Coupler 3 Coupler 2 Coupler

16 16 Removing inner tiles after finding that they charge up at 80K Consequence of low resistivities of absorber materials: Completely removed TT2 ferrite because some had fallen off Tried gold coating of TTE absorbers but coating may fall off Removed all tiles from the inside of the HOM absorber Found loose tiles during cryomodule disassembly Thermal stress tests confirmed this problem Solved by cutting stress relief slots in the tiles on top of removing TT2 ferrite Stress relief slots Beamside tiles removed December 17, 2009 Florian Loehl Georg H. Hoffstaetter Future Ligh Sources Workshop Status of Cornell s ERL 1 March 2010

17 17 Beamline String Assembly Attach cold couplers to beamline string Cavity He vessel pump port Cold coupler Beamline HOM load Gate valve internal to cryomodule Cleanroom assembly fixturing Vacuum vessel interface flange

18 18 Technical Details, Justification and critical needs for R&D Projects a) Continued Gun R&D b) ERL cryomodule construction a-c) Hi-brightness beam physics d) ERL Undulators e) Other X-ray beamline R&D Cornell Electron Storage Ring Tunnel b) e) a) c) d) Georg H. Hoffstaetter Future Ligh Sources Workshop Status of Cornell s ERL 1 March 2010

19 19 Importance of CW SRF research 50 Example Main Linac Cost Distribution for E=16.2 MV/m relative cost [%] Tunnel RF system Cryomodules Cryogenic plant High current, multi GeV SRF linacs for ERLs are great for hard x-ray sources The SRF components are the cost drivers of these novel accelerators Driving SRF challenges are the dynamics load and theirfor low loss technology. HOMs and their control become critical Microphonis and control becomes critical It is thus very much worth to invest in these research subjects.

20 20 Further preconstruction work: Main x-ray ERL cyromodule a) Continued Gun R&D b) ERL cryomodule c) Hi-brightness beam physics d) ERL Undulators e) Other X-ray beamline R&D Cornell Electron Storage Ring Tunnel d) e) a) b) c) Georg H. Hoffstaetter Future Ligh Sources Workshop Status of Cornell s ERL 1 March 2010

21 21 ERL SRF Power Consumption Pessimistic Parameter Units Value 10 MeV Injector (Cornell ICM) Injector RF Power kw 1000 Injector Cryo Heat Load W 40 ERL Eacc MV/m 20 Operating Temperature K 2 Qo 1.00E+10 Peak Microphonics Hz 20 Qe (Perfect ER) 3.30E+07 RF Power per Cavity (Perfect ER) kw 6.4 Pdiss per cavity W 41.6 Static Load per Cavity W 2 Second Pass Phase Deg Qe (Imperfect ER) 2.10E+07 RF Power per Cavity (Imperfect ER) kw 10 Total Number of Cavities 337 RF Power Overhead % 25 ERL RF Power (Perfect ER) kw 2699 ERL RF Power (Imperfect ER) kw 4229 ERL Cryo Power kw 14.7 Optimistic Value E E E Total Total Dynamic Load kw 14.1 Total Static Load kw 0.7 Cryo Safety Factor % 50 Cryo Efficiency ACW/W 800 Total Cryo Capacity kw 14.8 Total AC RF Power (Perfect ER) MW 7.4 Total AC RF Power (Imperfect ER) MW Total AC Cryo Power MW 17.7 Total AC Power (Perfect ER) MW 25.1 Total AC Power (Imperfect ER) MW Georg H. Hoffstaetter Future Ligh Sources Workshop Status of Cornell s ERL 1 March 2010

22 22 Example of Industry Connection: Cornell 500MHz cavities CLS CESR DIAMOND SSRF TLS Technology transfer to industry Technology transfer Turn-Key Systems 1999: Cornell University and ACCEL agreed on technology transfer of the 500MHz SRF module 2000: 2 SRF modules for NSRRC, Taiwan; delivered operational 2000: 2 SRF modules for Cornell, USA; delivered operational 2000: 2 SRF modules for CLS, Canada; delivered operational 2003: 3 SRF modules for DLS, Great Britain; delivered operational 2005: 3 SRF modules for SSRF, China; delivered operational Georg H. Hoffstaetter Future Ligh Sources Workshop Status of Cornell s ERL 1 March 2010

23 23 Component Prototyping: Delta Undulator 30cm long prototype of Delta undulator installed in beam line #2 at ATF (BNL) Electron beam image on flag downstream of the undulator Fundamental harmonics in planar mode Fundamental harmonics in helical mode Georg H. Hoffstaetter Future Ligh Sources Workshop Status of Cornell s ERL 1 March 2010

24 24 Component Prototyping: Phase 1a and 1b 1) Specify technological choices, cost, and construction time A) For the electron beamline done following mentioned RFP B) For gun and injector, following Phase 1a and Phase 1b funded prototyping C) For SRF linac following cryomodule construction of Phase 1b D) For x-ray beamlines a set of generic lines will be designed for costing which then can be modified by beamline teams before construction. 2) Cavity operations stability, Quality factor Q0, operations cost A) We produce cavities for the Int. CW Cryomodule in Daresbury B) Operation of cavities in our Horizontal Test Cryostat for large Q0 (at NSF) C) Operation of a full ERL cryomodule in Phase 1b. 3) Undulator construction cost and construction time in Phase 1b

25 25 SRF R&D synergetic with work for HEP DUSEL: Cavity design and prototyping for Project-X (ICD1 or ICD2), vendor development and qualification for Project-X and ILC. We are already part of the Project-X team via an MOU. SRF R&D: T-map analysis as tool for process influences on high gradients and high Q, highest Qs at medium fields, frequent Q degradation in accelerator cryostat environments. Muon collider: explosion bonded material testing (Nb on Cu for less cost and more heat transfer) with 500MHz cavities for cost and quicker turnaround (for reduced size compared to 200MHz).

26 26 Knowledge dissemination for Accelerators Editor: Frank Zimmermann (CERN) Associate Editors: Georg H. Hoffstaetter (Cornell) Brand M. Johnson (BNL) Senior Assistant Editor: Debbie Brodbar Focus Issue Accelerator and Beam Physics Editors: Georg Hoffstaetter (Cornell) Kwang-Je Kim (ANL) Ferdinand Willeke (DESY)

27 27 Education and workforce development Undergraduate and graduate students working on ERL injector with physics faculty (Cornell, Wilson lab, L0 area) Graduate Students: 10 accelerator physics, 4 of which SRF 9 high energy physics experiment

28 28 Accelerator Analysis and Documentation in a Comprehensive Design Report 1) Layout rather order complete 2) Operations simulation much still needed 3) BBU rather complete 4) Orbit correction 1 st order analyzed 5) Emittance growth 1 st order analyzed 6) Shielding 1 nd order analyzed 7) Front to end simulation much still needed 8) Sensitivity analysis 1 st order analyzed The full concept is to be documented by this summer in a CDR A) Overview including short science case B) x-ray beamline Generic beamlines C) Accelerator Accelerator Physics and Technolgy choices D) Conventional Facilities E) Management Including Safety F) Operations Transition, Reliability