Plasma Beam Dump, and Possible Experiment Tests at CLARA and AWAKE

Plasma beam dump, and possible experiment tests at CLARA and AWAKE

Guoxing Xia, Kieran Hanahoe, Oznur Mete, Yangmei Li, Yuan Zhao University of Manchester and the Cockcroft Institute

1 Contents

• Conventional beam dump

• Plasma beam dump

• Modelling of plasma beam dump

• Experiment tests at VELA/CLARA

• Conclusion

2 Conventional Beam dump-ILC ILC beam dump design:

• Stainless steel pressure vessel

• 11 m length

• 10 bar pressure, plus 100% safety margin

• 155 ℃ water temperature P. Satyamurthy et al., NIMA 679, 67 (2005) Challenges:

• Dump window must allow passage of beam while withstanding high pressure

• Radio-activation by photospallation

• Hydrogen/oxygen production

3 Noble gas beam dump - an alternative

• Noble gas at atmospheric density

• 1000 m length

• Low power density

• Less reactive chemicals

A. Leuschner, LC-ABD dump meetings (2005)

4 Plasma beam dump

A plasma beam dump offers high decelerating gradients in a low density medium:

25 –3 24 –3 c.f. density of air at 1 atm ~10 m For ne=10 m , Ewb=96 GV/m.

• Compared with the stopping power in a solid material e.g. ILC beam dump 500 GeV in 11 m = 45 GV/m.

• Plasma density is orders of magnitude lower than solid e.g graphite ~ 1029 m–3.

• Plasma beam dump can also be applied to positrons/muons with high decelerating gradient.

5 Plasma beam dump

Longitudinal phase space of plasma decelerated bunch Wu et al. proposed using foils to absorb low-energy particles.

H. C. Wu et al. PRSTAB 13, 101303 (2010)

Trajectory of decelerated particles

Re-accelerated portion of bunch

6 Active beam dump Passive beam dump Active beam dump

7 A. Bonatto et al. Phys. Plasmas 22, 083106 (2015) Varying plasma density

Plasma density increase puts low energy tail of the bunch into defocusing region

8 K. Hanahoe, et al., Phys. Plasmas 24, 023120 (2017) Varying plasma density 0 cm 5 cm 10 cm

9 15 cm 20 cm 25 cm Varying plasma density

Energy/transverse position plots after saturation length for uniform plasma (L) and gradient plasma (R).

K. Hanahoe, et al., Phys. Plasmas 24, 023120 (2017) 10 Varying plasma density

Total bunch energy loss for different plasma density schemes

Quantity of charge in a region 30 μm behind bunch head with energy > 30 MeV 11 Experiment tests at VELA/CLARA

e- from VELA/CLARA

Experiment test #1

Experiment test #2 12 Experiment tests at VELA/CLARA Laser out Laser in

Experiment test #3

• With the possibility to study the energy recovery in plasma

• High impact to the accelerator community (e.g. ILC) and novel accelerator community (e.g.EuPRAXIA)

• Key issues will be discussed in today’s workshop, with collaborators worldwide

13 Possible PWFA activities

14 Why proton?

Ø Large energy stored in proton machines like Tevatron, HERA, SPS and LHC Ø The SPS/LHC beams carry significant energy for driving plasma waves

Ø SPS (450 GeV, 1.3e11 p/bunch) ~ 10 kJ Ø LHC (7 TeV, 1.15e11 p/bunch) ~ 140 kJ

Ø SLAC (50 GeV, 2e10 e/bunch) ~ 0.16 kJ Ø ILC (250 GeV, 2e10 e/bunch) ~ 0.8kJ

One stage proton wakefied acceleration can generate energy frontier electron beam

04/09/18 15 Proton-driven PWFA

Drive beam: p+ 11 E=1 TeV, Np=10 σr=0.43 mm, σθ=0.03 mrad, 600 GeV e- beam σz=100 μm, ΔE/E=10 % ≤1% ΔE/E Witness beam: e- in ~500 10 plasma E0=10 GeV, Ne=1.5x10 Plasma: Li+ 14 -3 np=6x10 cm External magnetic ﬁeld: Field gradient: 1000 T/m Magnet length: 0.7 m Caldwell et al., Nature Physics 2009 04/09/18 16 AWAKE: Advanced WAKEﬁeld experiment

The primary goal of AWAKE is to demonstrate acceleration of a 16 MeV single bunch electron beam up to 1 GeV in a 10 m of plasma.

04/09/18 17 AWAKE timeline ‣ 2013 Approval of project at CERN including funding proﬁle. ‣ 2014-2015 Design, procurement and installation of the equipment, development of plasma cells. Modiﬁcation and installation of the beam line and the experimental facility. ‣ 2016 First proton beam to the AWAKE experiment, beam–plasma commissioning. Beginning taking data ‣ 2017 Installation of the electron source and beam line and diagnostics. Delivery and installation of the electron photo-injector, commissioning of the magnetic spectrometer. ‣ More data taking! ‣ International Effort ‣ 16 institutions in 9 countries across Europe and Asia.

04/09/18 18 AWAKE timeline

2016 Phase 1: Self-Modulation Instability physics 2017-18 Phase 2: Electron acceleration physics Run-scenario Nominal Number of run-periods/year 4 Length of run-period 2 weeks Total number of beam shots/year (100% efﬁciency) 162000 Total number of protons/year 4.86×1016 p Initial experimental program 3 – 4 years

04/09/18 19 AWAKE experiment layout

Laser power supplies Access gallery Items in dark blue: ventilation ducts Items in light blue: AWAKE electronic racks Items in cyan: existing CNGS equipment (cable trays, pipes,…) Lasers

Electron gun

Klystron system

Proton beam line 10m

Laser & proton beam junction

Electron beam line

Plasma cell (10m long)

Electron spectrometer

Experimental Diagnostics

CNGS target area

04/09/18 20 AWAKE Run I, Phase I

• Perform benchmark experiments using proton bunches to drive wakeﬁelds for the ﬁrst time ever. • Understand the physics of self-modulation instability processes in plasma. Laser Proton diagnostics 10m plasma cell OTR, CTR, TCTR Proton p beam dump Laser SPS plasma gas dump protons proton bunch laser pulse

plasma

0.0 ρ 0.20 beam

8.3 meters ρ Propagation direction

-0.4 ] ] e0 e0 [n 0.10 [n pe -0.8 radius (r) plasma Self-modulated proton beam ρ ρ bunch resonantly driving r plasma wakefields. -1.2

0.00 Proton beam density

Distance in beam (z) Plasma electron density

04/09/18 21 AWAKE Run I, Phase II

20m 10m 15m e- spectrometer Laser& RF&gun& EOS e- Diagnostics Proton& beam& dump& SPS Laser Acceleration protons SMI dump OTR, CTR Diagnostics

Scientific goals • Inject 10-20 MeV 1. Demonstrate self-modulation effect of a long proton bunch and electron beam realize 1 GeV electron energy gain with a ~10 m plasma • Acceleration of 2. Develop and test the diagnostic equipments for the first and electrons to multi- later experiments GeV energy range 3. Benchmark data against simulation results after the plasma exit. 4. Provide inputs for future experiment for 100 GeV in 100 m plasma

04/09/18 22 First beam June 2016

• First extraction of proton beam along the AWAKE line to identify or discard any issues • Check of optics, beam instrumentation, alignment of laser merging mirror, logging, etc… e- spectrometer Laser RF gun Plasma cell e 10m p - Proton beam dump Proton SPS SMI Acceleration Laser diagnostics protons dump

Proton Beam Image in last BTV screen downstream plasma 04/09/18 23 First milestone-self modulation (Dec. 2016)

Plasma off Plasma on 04/09/18 24 Seeded self modulation (SSM)

04/09/18 25 SSM

04/09/18 26 SSM

Stronger effects with seed at ¼ than ½ observed ! 04/09/18 K. Rieger, MPP 27 Micro bunch train

04/09/18 28 Interesting results observed

Observe SSM (defocusing, micro-bunches)

• Demonstrate seeding: SSM

• Micro bunch structure (very) stable against p+ variations: key for e- injection and acceleration,

• No seeding=> SMI or hose instability

• fmod~fpe

• Run II: (2021-): two plasmas, high quality of the accelerated e- bunch: ΔE/E, ε

• Application of AWAKE, e-/p+ collisions

04/09/18 29 Wakeﬁeld sampling/acceleration

04/09/18 30 Experimental setup for Run II (2021-LS3)

04/09/18 31 AWAKE Run II

LWFA based e- injector: synchronization, short bunch, high energy (100 MeV), high current, beam loading, beam quality…

04/09/18 32 AWAKE applications

Nuclear Instruments and Methods in Physics Research A ∎ (∎∎∎∎) ∎∎∎–∎∎∎

Contents lists available at ScienceDirect An e+ e- collider Nuclear Instruments and Methods in Physics Research A

journal homepage: www.elsevier.com/locate/nima

Collider design issues based on proton-driven plasma wakeﬁeld acceleration

G. Xia a,b,n, O. Mete a,b, A. Aimidula b,c, C.P. Welsch b,c, S. Chattopadhyay a,b,c, S. Mandry d, M. Wing d,e

a School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom b The Cockcroft Institute, Sci-Tech Daresbury, Daresbury, Warrington, United Kingdom c The University of Liverpool, Liverpool, United Kingdom d Department of Physics and Astronomy, University College London, London, United Kingdom e Deutsche Elektronen-Synchrotron DESY, Hamburg, Germany

article info abstract

Recent simulations have shown that a high-energy proton bunch can excite strong plasma wakefields Keywords: and accelerate a bunch of electrons to the energy frontier in a single stage of acceleration. It therefore PDPWA paves the way towards a compact future collider design using the proton beams from existing high- Colliders energy proton machines, e.g. Tevatron or the LHC. This paper addresses some key issues in designing a Self-modulation instability compact electron–positron linear collider and an electron–proton collider based on the existing CERN Dephasing accelerator infrastructure. An e-p collider & 2013 Elsevier B.V. All rights reserved. 04/09/18 33 1. Introduction proposed LHeC design employs the LHC beam colliding with the electron beam from a newly designed energy recovery linac (ERL) With the recent discovery of the Higgs boson at the Large based ring or from a linac [3]. However, this design is expensive, Hadron Collider (LHC) at CERN [1,2], the high energy physics e.g. the ring based design needs about 9 km tunnel and a 19 km community anticipated the construction of a dedicated Higgs bending arcs. The electron beam power is greater than 100 MW factory, which may be an electron–positron e e linear collider and the project is not listed as the high priority for the recently ð þ À Þ for the precise measurement of the properties of the Higgs updated European strategy for particle physics [4]. particle, e.g. its mass, spin, couplings with other particles and The development of plasma accelerators has achieved tremen- self-couplings, etc. However, current e þ e À linear collider designs dous progress in the last decade. Laser wakefield accelerators at the energy frontier (TeV, or 1012 electronvolts) such as the (LWFAs) can routinely produce GeV electron beams of percen- International Linear Collider (ILC) and Compact Linear Collider tage energy spread with only a few centimeter plasma cell and the (CLIC) extends over 30 km and costs over multi-billion dollars. The accelerating gradient 100 GeV=m is more than three orders of ð Þ sizes of these machines are heavily dependent on the length of the magnitude higher than the fields in conventional RF based RF linac, which is subject to a maximum material breakdown field structures [5]. Charged particle beam driven plasma wakefield (of 150 MeV=m) and is the main cost driver for next generation acceleration (PWFA) has successfully demonstrated energy dou- linear colliders. The obvious question is can we make the future bling from 42 to 85 GeV of the electron beam from the Stanford machine more compact and cost effective? Linear Collider (SLC) within an 85 cm plasma cell [6]. These In addition, the possibility of a lepton–hadron (e.g. ep) collider significant breakthroughs have shown great promise to make a at CERN has been of interest since the initial proposal of the LHC. It future machine more compact and cheaper. Based on these LWFA/ has long been known that lepton–hadron collisions play an PWFA schemes, a future energy frontier linear collider will consist important role in the exploration of the fundamental structure of of multi-stages, on the order of 100/50, to reach the TeV energy matter. For example, the quark-parton model originated from scale with each stage yielding energy gains of 10=20 GeV. It investigation of electron–nucleon scattering. The currently should be noted that the multi-stage scheme introduces new challenges such as tight synchronization and alignment require- ments of the drive and witness bunches and of each accelerator n Corresponding author at School of Physics and Astronomy, University of module (plasma cell). Staging also means a gradient dilution due Manchester, Manchester, United Kingdom. Tel.: +44 161 30 66569. E-mail address: [email protected] (G. Xia). to long distances required between each accelerator module for

Please cite this article as: G. Xia, et al., Nuclear Instruments & Methods in Physics Research A (2013), http://dx.doi.org/10.1016/j. nima.2013.11.006i Hollow plasma channel

on-axis acc field

Mean energy and energy spread of the WB Initial value: 2.0 mm 2D plasma wakefields mrad proto n bunc • No transverse plasma 2.4 mm h fields + larger acc mrad gradients on the witness electro electron bunch n Y.bunch Li et al., to be published at Phys. Rev. Accel. Beams 2017 04/09/18 34 Conclusions

• Plasma beam dump can absorb beam energy with reduced radio-activation

• Varying plasma density can be used to improve the energy loss of a passive plasma beam dump

• Plasma beam dump can be tested at the VELA/CLARA using the existing beam diagnostics

• VELA/CLARA and AWAKE facility can be used to test the energy recovery

Thank you very much !