& o riF~ 9srosr29?~ i/^^ 1A-UR- 95 "3 3 §-5%. TITLE: HIGH INTENSITY SRF PROTON LINAC WORKSHOP (VUGRAPHS) S° £*§!* 2 5 ItfS § •s^2,§ I? AUTHOR(S): •-(3D CD « Brian A. Rusnak and AOT-1 o g CD a II Several external authors So --I; !-' i J*> a . c ca a g E a a o..2 (500 double-sided a 4> ,0 u £ 00 O •" « 6*3 o g • vugraphs) TS S 2 c _. ,1 o. «> ""S8SI Is M E t S II 'S « O O Si * 5- II "S2 O« g B.to & S - p l'i is 8 » s* « '3 o s ii 1? SUBMITTED TO: High Intensity SRP Proton Linac Workshop. •?« I Santa Fe, NM •It! •5 -c May 7-10,1995 o o li §2 n J3 a E f£§iI 8f 11I NATIONAL LABORATORY Los Alamos National Laboratory, an affirmative action/equal opportunity employer, is operated by the University of California for the U.S. Department of Energy under contract W-7405-ENG-36. By acceptance of this article, the publisher recognizes that the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or to allow others to do so, for U.S. Government purposes. The Los Alamos National Laboratory requests that the publisher identify this article as work performed under the auspices of the U.S. Department of Energy. Form No. 836 R5 DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED ST 262910.91 DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. Proceedings for the High-Intensity SRF Proton Linac Workshop May 7-10, 1995 Hotel Santa Fe Santa Fe, NM General Introduction Opening Remarks P. Lisowski Page APT Accelerator Overview G. Lawrence Page Operating Experience Talks TRISTAN SRF System S. Noguchi Page CEBAF: status, outlook, C. Leemann Page and lessons learned H. Klein Page ESS Linac Design D. Chan Page APT Superconducting RF Linac High Current High Gradient Superconducting Cavities H. Padamsee Page Cavitv-Structures Working Group Summary Report T. Wangler, J. Delayen (Chairmen) Page Summary Viewgraphs J. Delayen Page Presented Viewgraphs Linac Architecture T. Wangler, E. Gray Page Cavity Design F. Krawczyk Page Structural Considerations R. Genzlinger Page CEBAF Experience A. Hutton Page Beam Physics C. Bohn Page Cryostat Candidate Design R. Gentzlinger Page R&D Program and Discussion T. Wangler Page Couplers and rf Working Group Summary Report P. Tallerico, H. Padamsee (Chairman) Page Summary Viewgraphs H. Padamsee Page Presented Viewgraphs rf Architectures D. Rees Page Coupler Comparison H. Padamsee Page Window Assessment H. Padamsee Page Power for HPP H. Padamsee Page HOM Coupler H. Padamsee Page R&D Recommendations H. Padamsee Page Upgrade Paths J. Delayen Page System Integration Working Group Summary report T. Moore, Chairmen Page Summary Viewgraphs K. Bongardt Contributed Viewgraphs RT linac For Protons J-M. Lagniel Page Design Of A Superconducting H. Heinrichs Page H-Linac for ESS GENERAL INTRODUCTION Opening Remarks Presentation to the High-Intensity SRF Proton Linac Workshop May 7-10, 1995 Paul Lisowski Los Alamos National Laboratory APT Project Leader APT Major Subsystem Features Accelerator Target/Blanket • Produces and • Produces neutrons accelerates from proton beam proton beam • Converts 3He (or 6Li) into tritium High-Energy Tritium Beam Transport Processing • Proton beam delivery • Continuous tritium to Target/Blanket extraction • Expands and shapes • Purification to weapons beam grade tritium APT Design Objectives Meet tritium production requirements with adequate margins Use existing technology wherever possible Simplicity High reliability Safety by Design Waste minimization APT Design Parameters Over Time 1989 1990 1991 1992 1993 1994 1995 1600 MeV 800 MeV 1000 MeV 1000 MeV 250 mA 150mA 200 mA 100mA Full Goal 1/4 Goal 3/8 Goal 3/16 Goal JsBk A ERAB 1992 JASON 1995 JASON Review Review Review Expectations from Project Office • Update on status of SCRF technology worldwide • Get concensus opinion from SCRF community - Technology maturity - Applicability to APT * • Identify areas needing further work - Identify where that work can be done - Determine how to proceed APT Accelerator Overview George Lawrence Los Alamos National Laboratory Workshop on High-Intensity SRF Proton Linac Design Sfttita Fe, NM 8-10, 1995 Evolution of APT Linac Design Raa*awigaaMaanMM(iMiMHiMaaBWM^^ •• 1992 Basic linac concept reviewed by JASONs - conservative design philosophy _. — design choices within present technology base, or moderate extensions • 1992-3 DOE-funded design study - 200-MW beam power requirement; production by 2008 • - 1000-MeV, 100-mA tunneled RT linac - preconceptual design report - detailed cost estimate • 1994 Power requirement reduced to 100 MW, with upgrade potential to 200 MW - non-funnelad 1000-MeV, 100-mA RT linac - upgrade to 200 mA by adding LE linac, funnel, RF power / LANL High-Power Linac Concept 1000-MeV, 200-mA CW Funneled System Funnel 350^. Coupled Cavity Linac (CCL) (700 MHz, 200 mA) . BCDTL 14-Cell Tanks (700 MHz) 100 MeV Doublet Focusing 1000 MeV 20MeV 7.0 MeV Matching & Halo Scraping 75keV 30 m 110m- 1040 m- Beam power 200 MW Total RF power to %i*K> 264MW RF to beam'tffkttwitey 0J87 AC to RF efflQJfcrtoy \ 0,582 RF trans^ort^tf^l^ricy 0-950 AC to beam effifefeticy 0.435 AC power faqutferftertt 405 MW CCL structMne^r&$#r»t 1,3-1.5MV/jn Transverse, .9$$!$ £jnjjttance 0,04 n cmTii)ravd CCL apm^M^m^m ratio 13-26 1000-MeV, 700-MHz Coupled-Cavity-Linac for APT Side-couplea n/2-mode structure similar to LAMPF 1000 MeV module Short tanks (14 cells) allow strong focusing • Structure power: 130 kW CW cooling for 1.4 MV/m • RF efficiency: •• 0.83 structure gradient • Energy gain: 3.0 MeV wr.ir—*• Los Alamos APT Output Beam Distribution From End-TorEnd Linac Simulation Ideal Linac —1000 MeV, 10,000 Macropartirles .005 .005 xp vs. x <cri-rad) .002 fett 0. .002 -.0 X «$ « 50 -1.25 0. 1.25 2.50 50 -1.25 0.. 1.25 2.50 8.00 e-es ve,"phl-phlB (Mev-deg) +.00 0. -4.00 -' e9"100^.Z6£ pB=-2qj*_ -8 € 50 -1.25 0. 1.25 2.50 -J0.O98, O -15,00 0. 15.00 30.0U LAMPF experience and APT design features provide confidence that beam losses will be low enough for hands-on maintenance. 10.0 ] Beam loss in LAMPF CCL estimated from activation (3 months operation at 1 mA) w Relative beam loss predicted by simulation w o (normalized at 100 MeV) "8 E W 111 R°rrn-i-iQ|U°i 300 400 500 600 700 800 Proton Energy (MeV) LAMPF APT Design Beam loss in much of CCL is very low Losses must be < 10-8/m at 1000 MeV. (<2x10-7/m). Strong focusing provides very large Activation levels are a few mR/hr. aperture ratio (13-26 in CCL). Most loss is from RF/beam mismatch Large acceptance transitions avoided, in turn-on transients. above 20 MeV. High losses from longitudinal and Precise matching between adjacent . transverse acceptance transitions. accelerating structures. Moderate aperture ratio (4-6.3). Halo scraping at 20 MeV. Evolution of APT Linac Design 1994-5 New RT linac design, based on - CCDTL .to replace low-p, transition-p structures - improved focusing lattice (short-period FODO) - RF modularization scheme for increased availability 19.95 Reviews by LLNL, JASONs - agree presented baseline design would do the job - endorse move to new RT concept (CCDTL, FODO lattice) - suggest assessment of SRF technology for HE linac 1995 Recent discussions with "customers" suggest - beam power requirement will be about 130 MW - desired initial production date is late FY2005 700-MHz CCDTL as Basis for Improved Linac Design iy*-mounted TMoi* coopSog ceB Low. energy - 2 drift-tubes per cell - 5pA/2, 3pA/2 - Could follow R.FQ - Increases, fuonefeg energy options. Quadrupole lens Two-<Jri<Mube CCOTL accelerating cavity Longer coupling celt Intermediate energy - 1 drift-tube per cell - 3pX, 1 $\ - Replaces BCDTL Short coupling ceR Sideways-mounted coupling cefl Conventional coupling cefl spanning the pX/2 bead spsce between cavities High energy - Conventional SCL - 7 cells per tank -.- 7 pA/2, 1 pA/2 - Cell can be omitted for diagnostics. Los Alamos Baseline Conventional Linac for 3/16-Goal Potential Beam Transport Injector Funnel Point I 350 MHz 700 MHz / 700 MHz 700 MHz m WWP Targets 100 mA | 100mA 100 mA 75 keV 7 MeV 12MeV 100 MeV 1000 MeV 100MW ppwer J355\!V!W %£:££& ^ 130 rfi - ! *$< APT Advanced Linac Concept for 3/16-Goal Beam Transport Injector 350 MHz 700 MHz APT Principal Issues for High Power Linacs • Cost - construction post (RF power dominates) - life-cycle cost (NPV) • Power conversion - AC-RF efficiency * -' RF-beam efficiency • pperability - beam (oss control; halo suppression - function of key components at high power levels - RF generator/cavity/beam control - turn-on, fault handling, system protection • Availability - component lifetime; failure diagnostics - replacement/service time intervals - component redundancy Neutron Production Efficiency vs Proton Energy (cylindrical Tungsten target 50-cm diam x 100-cm-long) 100 500 1000 1500 2000 'Proton Energy (MeV) Linac AC-to-Beam Efficiency vs Proton Energy ^0.2 o 03 C 50 mA @ 1 GeV ZJ 0.1 0 I 1 • i i • • • • ' • • • • 0 500 1000 1500 2000 Proton Energy (MeV) Neutron Production per Watt of Linac Power wmmmmm 10 -i 1 1 r I I I I 1 1 1 r 200 mA @ 1 GeV 8 CO o cCO 50mA@1GeVi CD CL •§• c ••—2* CD z: 0 • I ,, .1 I 1 1 L. • • • 0 500 1000 1500 2000 Proton Energy (MeV) Where Does the Power Go in the APT System? 100-mA, 1000-MeV System (355 MW Plant Power) Waveguide AC-DC Conversion Losses Losses 8MW 5MW , **:*::i::':iiU:::::i:i!iSiii::ji':'!'' Present Baseline RT Linac Design for Comparison with SRF Point Design 100-MW non-funneled linac (1000 MeV, 100 mA) 7-MeV, 350-MHz RFQ 100-MeV, 700-MHz CCDTL 1000-MeV, 700-MHz GCL FODO focusing lattice in CCDTL, CCL (8pX) Aperture factor > 13 - 26 (100 MeV -1000 MeV) Linac is divided into modules, each driven by seven 1-MW klystrons; can tolerate single tube failure Objectives of the High-Power SRF Linac Workshop • Critique a strawman SRF linac point design.