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1 1 mucool Andreas ggenberger on behalf of the mucool collaboration: A. Antognini, I. Belosevic, A. ggenberger, K.-S. Khaw, K. Kirch, F. M. Piegsa, D. Taqqu, G. Wichmann Institute for Particle Physics, TH Zurich, 893 Zurich, Switzerland M. Hildebrandt, A. Knecht, A. Papa, C. Petitjean, N. Ritjoho, S. Ritt, K. Sedlak, A. Stoykov Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland D. M. Kaplan, T. J. Phillips Illinois Institute of Technology, Chicago, IL 6616, USA

2 2 mucool: Goals We are building a small device to compress the phase space of a surface µ + beam Compress phase space by 1 orders of magnitude nergy of µ + <1 ev Beam size <1 mm 2 fficiency ~1-3 Tagged beam Conserves initial polarisation Add-on to existing conventional surface µ + beam line

3 3 Phase Space Compression To reduce phase space a dissipative mechanism is needed Slow down (stop) µ + in He gas After slowing down in gas: low energy large volume BUT: can steer µ + with electric and magnetic fields In our case: Apply xb-fields in 3 successive compression stages: 1. Transverse (perpendicular to beam axis) 2. Longitudinal (along beam axis) 3. Final compression and extraction into vacuum

4 4 Key Ingredient Position-dependent drift velocity vector in He gas in the presence of crossed electric and magnetic fields ω=eb/m: cyclotron frequency µ=muon mobility νcol=collision frequency 3 components with different weights: change in density (i.e. collision frequency) change in direction

5 5 3 Compression Stages Dimensions ~ 15 x 5 x 5 cm 3 z y x B=5 T B Transverse compression Longitudinal compression xtraction into vacuum 5 mbar He Outgoing µ + beam D<1 mm <1 ev tagged beam Incoming µ + beam D~1 mm =4.1 MeV continuous beam D. Taqqu, PRL 97, (26) Y. Bao et al., PRL 112, (214)

6 6 Transverse Compression Stage 5 mbar He gas B Cryogenic temperature Temperature gradient Crossed - and B-fields y z x 12 K 4 K B

7 7 Longitudinal Compression Stage B y Simulation: Top view x z 5 mbar He gas Room temperature Parallel - and B-fields µ + from transverse stage z [mm] Towards extraction 4 8 x [mm]

8 8 Status: The Path to Muon Beam Compression 211: First test of longitudinal compression Y. Bao et al., PRL 112, (214) 213: Demonstration of stationary He gas density gradient G. Wichmann et al, NIM A 814, (216) 214: Improved longitudinal setup ngineering run for transverse compression 215: Longitudinal compression with subsequent xb-drift Demonstration of transverse compression Still to do: Combination of transverse and longitudinal compression xtraction into vacuum xtraction from B-field & re-acceleration

9 9 Longitudinal Setup B y drift detectors z x B He volume: 25 x 12 x 3 mm 3 Kapton foil with electrodes Longitudinal injection () 5 mbar He Pairs of compression detectors xb-drift detectors µ + pairs of compression detectors

10 1 Longitudinal Target He volume Almost finished target 1 cm HV connections, detectors and brass shielding 5 cm Scintillators

11 11 Longitudinal Compression B HV y µ + 5 mbar He z x ntrance detector π1 beam 9.1 MeV/c ~11 khz on entrance detector µ + cross entrance detector -> t= few % µ + stop in He gas target Apply electric potential Detect decay e + at time t

12 12 Longitudinal Compression B HV y µ + 5 mbar He z x ntrance detector π1 beam 9.1 MeV/c ~11 khz on entrance detector µ + cross entrance detector few % µ + stop in He gas target Apply electric potential Detect decay e + at time t counts exp(t/22) counts/exp[-t/22] [a.u.] V +55 V V PRLIMINARY Central detectors in coincidence time [ns]

13 13 xb-drift B Towards extraction µ + 5 mbar He y z x Add vertical (y) component to -field off-center injection of µ + µ + drift in xb-direction

14 14 xb-drift B Left Middle Right counts exp(t/22) counts/exp[-t/22] [a.u.] Left Middle Right PRLIMINARY µ + 5 mbar He y time [ns] Compression Dominated by xb-drift z x Add vertical (y) component to -field off-center injection of µ + µ + drift in xb-direction

15 Transverse Compression B Cold finger

16 Transverse Compression B First complete assembly Cold temperatures reached Positron detectors worked Beam alignment understood Gas leak at cold temperatures HV problems: HV dividers and connectors on sapphire lectric discharges Cold finger

17 Transverse Compression B First complete assembly Cold temperatures reached Positron detectors worked Beam alignment understood Gas leak at cold temperatures HV problems: HV dividers and connectors on sapphire lectric discharges 1 year of improvements Leak tight at cold, even after several thermal cycles Temperature gradient: K (inside 5 T solenoid) HV stability: Up to mbar, 6-18 K

18 18 Transverse Target During construction Finished target 1 cm Scintillators wrapped in Teflon Andreas ggenberger (TH Zurich) Setup at π1 mucool

19 19 Simulations of Transverse Compression 18.6 K B 6.1 K No temperature gradient Temperature gradient no position-dependent position-dependent

20 2 Demonstration of Transverse Compression Det 1 Det 1 B No temperature gradient Temperature gradient counts / exp[-t/22] counts exp(t/22) [a.u.] Detector Crash into wall Fly by the detector PRLIMINARY time [ns]

21 21 Demonstration of Transverse Compression Det 1 Det 1 Det 2 Det 2 B No temperature gradient Temperature gradient counts / exp[-t/22] counts exp(t/22) [a.u.] Detector Crash into wall Fly by the detector PRLIMINARY time [ns] counts / exp[-t/22] Detector time [ns] counts exp(t/22) [a.u.] PRLIMINARY Compress into tip Don t reach tip

22 22 Conclusion 4 weeks of beam time in 215 Longitudinal compression with low background xb-drift after longitudinal compression Transverse setup works well Transverse compression demonstrated 216: Further setup development Data analysis, comparison with simulations Combine cold transverse and warm longitudinal stage Test extraction into vacuum Requires about 1 year of lab work & offline tests

23 23 Thanks to: Konrad Deiters Florian Barchetti Franz Kottmann Urs Greuter Thomas Prokscha Robert Scheuermann Michael Horisberger PSI and TH workshops PSI support groups and thank you for your attention

24 24 Back ups

25 25 Impurities t/22 normalized counts / e T1 with T2 Coincidence Run mucoo_117-5 V V 5 mbar +5 V -5 V,.2 mbar H2-5 V,.1 mbar O time [ns]

26 Simulation: Transverse Compression 26 (D. Taqqu, 26)

27 Simulation: Full Compression 27 (D. Taqqu, 26)

28 Simulation: Projections of Compression 28 (D. Taqqu, 26)

29 29 nergy loss

30 3 Acceptance Map 215 A1s A2R A2L A2Fibre A3s A A4c A4Fibre A

31 31 ngineering Run of Transverse 214

32 32 Density Gradient (I)

33 33 Density Gradient (II) 1 8 Ρ a.u x a.u y a.u.

34 34 xtraction from Vacuum

35 35 xtraction from B-Field

The Muonium Antimatter Gravity Experiment Testing to see if something is the Matter with Gravity. Thomas Phillips IIT

The Muonium Antimatter Gravity Experiment Testing to see if something is the Matter with Gravity Thomas Phillips IIT 1 Outline 1. Motivation: What if we are wrong about antimatter gravity? 2. Why Muonium