Eric Prebys FNAL Snowmass Miniworkshop on Frontier Capabilities

Eric Prebys, FNAL Snowmass Mini-workshop on Frontier Capabilities University of Chicago, February 25 -26, 2013 Minneapolis

Primary contacts: (big thanks to) Lucio Rossi, Oliver Brüning, Frank Zimmermann Primary Resources “LHC Design Report” (2004), [http: //lhc. web. cern. ch/lhc-designreport. html] “High Luminosity LHC (European Strategy Report)” (2012) [http: //cdsweb. cern. ch/record/1471000/files/CERN-ATS-2012 -236. pdf] “HL-LHC Parameter and Layout Committee” Website [https: //espace. cern. ch/Hi. Lumi/PLC/default. aspx] “HE-LHC’ 10 Mini-Workshop” (2010) [http: //indico. cern. ch/conference. Display. py? conf. Id=97971] “High Energy LHC, Document Prepared for European Strategy Update [http: //cdsweb. cern. ch/record/1471002/files/CERN-ATS-2012 -237. pdf] Snowmass/Eu. CARD/Hi. Lumi “Frontier Capabilities” Workshop (2013) [https: //indico. cern. ch/conference. Display. py? conf. Id=223094] Eric Prebys, Uof. C Mini-Workshop February 25 -26 2

Facility C. M. Energy Luminosity (1034 cm-2 s-1) Start Date Status Nominal LHC 13 -14 Te. V pp 1 2 Peak 2014 Planned and scheduled HL-LHC 14 Te. V pp 5 Leveled 2024 In planning HE-LHC 33 Te. V pp (LHC tunnel) 5* ~2035 Proposed VHE-LHC 70 -100 Te. V pp (new 80 -100 km tunnel) 5* after 2035 Proposed Not discussed Higgs and Tera-Z factories: LEP 3 (LHC tunnel), TLEP (80+ km tunnel) e. P options: LHe. C, VHE-LHe. C Caveat Numbers for LHC and HL-LHC are reasonably solid HE-LHC and LHe. C are in a state of constant development and refinement. They’ve changed since the kickoff meeting This represents one snapshot *increased since kick-off Eric Prebys, Uof. C Mini-Workshop February 25 -26 3

Reach nominal energy Maximize current/brightness Time Line: LS 1: “Nominal” (2013 -2014) Complete repairs of the superconducting joint and pressure relief problems which cause “the incident” in 2008 and currently limit the energy to 4+4 Te. V. “Lost memory” issues may limit the beam energy to somewhere between 6. 5 and 7 Te. V per beam. LS 2: “Ultimate” (2017) injector and collimation upgrades Increase current and/or lowering emittance, increasing the luminosity further LS 3: “HL-LHC” (~2022 -2023) Lower b* and compensate for crossing angle to maximize luminosity Eric Prebys, Uof. C Mini-Workshop February 25 -26 4

Bunch Spacing Parameter 25 ns 50 ns Beam Energy [Te. V] 6. 5 -7 nb 2808 1404 Nb 1. 15(1. 7)x 1011 1. 7(2. 0)x 1011 p b* [m] . 55 sx, y [mm] 16. 7 sz [cm] 7. 6 Total Energy/beam [MJ] 362 (535) 267 (314) L (peak) [1034 cm-2 s-1] ~1 (2) Events/crossing 27 (54) 54 (108)** L (integrated) [fb-1/year] 40 (80) L (integrated) [fb-1, total by 2022] ~300 *“Ultimate” parameters shown in parenthesis. Other combinations are possible. **It is unlikely that the experiments will be able to handle this pile-up, and therefore the luminosity will have to be limited to something lower if we are running with 50 ns spacing. Eric Prebys, Uof. C Mini-Workshop February 25 -26 5

Reduce b* from 55 cm to 15 cm Requires large aperture final focus quads Beyond Nb. Ti Requires Nb 3 Sn never before used in an accelerator! BUT, reducing b* increases the effect of crossing angle “Piwinski Angle” Eric Prebys, Uof. C Mini-Workshop February 25 -26 6

Original goal of luminosity upgrade: >1035 cm-2 s-1 Leads to unacceptable pileup in detectors New goal: 5 x 1034 leveled luminosity Options Crab cavities b* modifications Lateral separation Eric Prebys, Uof. C Mini-Workshop New: experiments don’t want crab leveling because linear multiplicity density not reduced! February 25 -26 7

Bunch Spacing Parameter 25 ns 50 ns Beam Energy [Te. V] 7 7 nb 2808 1404 Nb 2. 2 x 1011 3. 5 x 1011 p b* [m] . 15 sx, y [mm] 7. 5 sz [cm] 7. 6 Total Energy/beam [MJ] 692 550 L (leveled) [1034 cm-2 s-1] 5 2. 5** Events/crossing 140 L (integrated) [fb-1/year] 250 L (integrated) [fb-1, total by 2030 s] ~3000 *Taken from latest “Parameter & Layout Committee” parameter table: [https: //espace. cern. ch/Hi. Lumi/PLC/default. aspx] **Limited at experiments’ request to reduce pile-up Eric Prebys, Uof. C Mini-Workshop February 25 -26 8

The energy of Hadron colliders is limited by feasible size and magnet technology. Options: Get very large (eg, VLHC > 100 km circumference) More powerful magnets (requires new technology) Eric Prebys, Uof. C Mini-Workshop February 25 -26 9

Traditional Nb. Ti Basis of ALL superconducting accelerator magnets to date Largest practical field ~8 -9 T Nb 3 Sn Advanced R&D, but no accelerator magnets yet! Being developed for large aperture/high gradient quadrupoles Largest practical field ~15 -16 T High Temperature Industry is interested in operating HTS at moderate fields at LN 2 temperatures. We’re interested in operating them at high fields at LHe temperatures. Mn. B 2 promising for power transmission can’t support magnetic field. YBCO very high field at LHe no cable (only tape) BSCCO (2212) Focusing on this, but strands demonstrated very expensive unmeasureably high field at LHe pursue hybrid design Eric Prebys, Uof. C Mini-Workshop February 25 -26 10

P. Mc. Intyre 2005 – 24 T ss Tripler, a lot of Bi-2212 , Je = 800 A/mm 2 E. Todesco 2010 20 T, 80% ss 30% Nb. Ti 55 %Nb. Sn 15 %HTS All Je < 400 A/mm 2 Eric Prebys, Uof. C Mini-Workshop February 25 -26 11

Injection energy will be ≥ 1 Te. V, beyond the range of the SPS Two options: SPS injects into a new Low Energy Ring (LER), which shares the tunnel with the HE-LHC* Super-ferric “Pipetron” magnets Technically “easy” Difficult to fit! New SPS+ 450 Ge. V -> 1 Te. V 24 injections -> Rapid cycling SC magnets Based on SIS-100 and SIS-300 at FAIR Synergy with EU LBNE program (Laguna) *H. Piekarz, Malta HE-LHC Workshop (2010) Eric Prebys, Uof. C Mini-Workshop February 25 -26 12

Parameter HL-LHC HE-LHC Beam Energy [Te. V] 7 16. 5 Injection Energy [Te. V] . 450 ≥ 1 Bunch Spacing [ns] 25 50** nb 2808 1404 Nb 2. 2 x 1011 1. 6 x 1011 p b* [m] . 15 . 3 sx, y [mm] 7. 1 ~10 sz [cm] 7. 6 ~6 Total Energy/beam [MJ] 692 593 L [1034 cm-2 s-1] 5 (leveled) 5 (peak or leveled) Events/crossing 140 ~280 (? ) L (integrated) [fb-1/year] 250 150 * First pass only. This luminosity was set to keep the energy deposition in the final focus magnets ~same as HL-LHC. Could certainly go higher if machine protection and magnets can handle it. Leveling likely. ** 25 ns also possible, but 50 ns reduces current and simplifies machine protection Eric Prebys, Uof. C Mini-Workshop February 25 -26 13

Several locations have been studied for the possibility to construct an 80 km ring tunnel in the CERN area. Nb 3 Sn Magnets: ~70 Te. V/beam 20 T hybrids: 100 Te. V/beam Location constraints CERN area Connected to LHC/SPS at one point Depth (access shafts) Circumference Average Depth Max Depth below surface LEP/LHC 27 km 100 m 170 m Jura 80 km 590 m 1270 m Lakeside 80 km 280 m 690 m Lakeside 47 km 220 m 320 m Least limestone = best *Talk by John Osborne, Joint Eu. CARD/Snowmass Workshop Eric Prebys, Uof. C Mini-Workshop February 25 -26 14

SPS+ LER VHE LER Your Text Here From H. Piekarz Malta Prooc. Pag. 101 30 mm V gap 50 mm H gap *Lucio Rossi, Snowmass/Eu. CARD Workshop (2013) Eric Prebys, Uof. C Mini-Workshop February 25 -26 15

Parameter HL-LHC HE-LHC VHE-LHC Beam Energy [Te. V] 7 16. 5 50 Injection Energy [Te. V] . 450 ≥ 1 ≥ 3 Bunch Spacing [ns] 25 50 50 nb 2808 1404 4210 Nb 2. 2 x 1011 1. 6 x 1011 p 1. 6 x 1011 b* [m] . 15 . 3 . 9 sx, y [mm] 7. 1 ~10 sz [cm] 7. 6 ~6 ~6 Total Energy/beam [MJ] 692 593 5390 (!!) L [1034 cm-2 s-1] 5 (leveled) 5 (peak or leveled) Events/crossing 140 ~280 (? ) ~300 L (integrated) [fb-1/year] 250 ≥ 100 ≥ 150 Injection by LER in same tunnel, which might also be TLEP e+e- ring? *Talk by Frank Zimmermann, Joint Snowmass/Eu. CARD Meeting Eric Prebys, Uof. C Mini-Workshop February 25 -26 16

It makes sense to consider exotic magnet solution if one is constrained to the LHC tunnel, however In addition to the extreme technical risk, the cost of 80 km of hybrid HTS magnets would be ~$16 B* Magnets made of pure Nb 3 Sn would be 65 -75% of the field and be 55% of the cost** Differential magnet $ > tunnel $, so scaling length will always be cheaper In addition, might be less risk and similar cost to go from 80 km-> 100 km because it gets around limestone in the Salève*** Stick with Nb 3 Sn for VHE-LHC, in my (correct) opinion *E. Todesco costs for HE-LHC (Malta workshop), scaled to 80 km **E. Todesco, Joint Snowmass/Eu. CARD workshop ***J. Osborne, Joint Snowmass/Eu. CARD workshop Eric Prebys, Uof. C Mini-Workshop February 25 -26 17

Magnets, magnets New conductors: Nb 3 Sn, HTS, hybrid designs eg, LARP, MAP, and base magnet programs Rapid cycling SC magnets Currently being developed for FAIR Rad hardness and energy deposition studies (simulation and experiment). eg, LARP energy deposition work Machine Protection Stored energy in VHE-LHC will be 15 times nominal LHC (2500 sticks of dynamite!!) Collimation design and materials research Novel collimation techniques Crystal collimation Hollow electron beam halo removal Loss mechanisms and halo formation (historically not so accurate) Eric Prebys, Uof. C Mini-Workshop February 25 -26 18

Crossing angle issues Crab cavity development LARP + European programs High brightness beams New ideas: eg, flat beams and crab waists Being studied for HL-LHC using circular eigen-emittances* Synchrotron radiation flat beams “easy” for VHE-LHC Compact magnets for beam separation within detectors “slim” magnets *eg, work of A. Burov Eric Prebys, Uof. C Mini-Workshop February 25 -26 19

Existing accelerators LHC: beam loss studies, electron clouds SPS: crab cavity tests, flat bunch studies Radiation damage and test facilities CERN Hi. Rad. Mat facility BNL Radiation damage facility Magnet and RF test facilities National labs and CERN Accelerator test facilities ASTA (IOTA): beams stability, loss mechanisms, crab cravities PXIE: physics of intense beams Eric Prebys, Uof. C Mini-Workshop February 25 -26 20

Eric Prebys, Uof. C Mini-Workshop February 25 -26 21

Technical Challenges Crab cavities have only barely been shown to work. Never in hadron machines LHC bunch length low frequency (400 MHz) 19. 2 cm beam separation “compact” (exotic) design Additional benefit Crab cavities are an easy way to level luminosity! Eric Prebys, Uof. C Mini-Workshop February 25 -26 22

Total Current, limited by • instabilities (eg, e-cloud) • machine protection issues! number of bunches Bunch size Geometric factor related to crossing angle and hourglass effect “Brightness”, limited by • Space charge effects • Instabilities • Beam-beam tune shift (ultimate limit) b*, limited by • magnet technology • chromatic effects *a la Frank Zimmermann Eric Prebys, Uof. C Mini-Workshop February 25 -26 23