Towards the production of an anti-hydrogen beam

Simon Van Gorp1, Y.Enomoto1, N.Kuroda2, K.Michishio3, D.J.Murtagh1, S.Ulmer1,, H. Higaki, C.H.Kim2, Y.Nagata1, Y.Kanai1, H.A.Torii2, M.Corradini4,

M.Leali4, E.Lodi-Rizzini4, V.Mascagna4, L.Venturelli4, N.Zurlo4, K.Fujii2, M.Otsuka2, K.Tanaka2, H.Imao5,Y.Nagashima3, Y.Matsuda2, B.Juhász6, A.Mohri1

and Y.Yamazaki1,2

1/25

Graduate School of Advanced Sciences of Matter, Hiroshima University,Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan

1 RIKEN Advanced Science Institute, Hirosawa, Wako, Saitama 351-0198, Japan2 Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan

3 Department of Physics, Tokyo University of Science, Kagurazaka, Shinjuku, Tokyo 162-8601, Japan4 Dipartimento di Chimica e Fisica per l’Ingegneria e per i Materiali, Universitá di Brescia & Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Brescia, 25133 Brescia, Italy

5 RIKEN Nishina Center for Accelerator Based Science, Hirosawa, Wako, Saitama 351-0198, Japan6 Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, 1090 Wien, Austria

(ASACUSA-MUSASHI)

Why Antihydrogen ?

*Antihydrogen is the simplest atom consisting entirely of antimatter. *Hydrogen counterpart is one of the best understood and most precisely measured atoms in physics.*A comparison of antihydrogen and hydrogen offers one of the most sensitive tests of CPT symmetry.

If there is some asymmetry we may get aware of it comparing mirrored systems which are

fully understood.

GOAL

High precision spectroscopy of the ground state hyperfine splitting of antihydrogen.

HOW?

Rabi spectroscopy of a spin-polarized anti-atomic beam.

4/25Low energy anti-hydrogen atoms (Level diagram)

experiments (Hz) Dnexp /n |ntheory-nexp |/n

n1S-2S 2,466,061,413,187,103(46) 1.7 x 10-14 1 x 10-11

nHFS 1,420,405,751.768(1) 6.3 x 10-13 (3.5+0.9) x 10-6

(F,M)=(1,-1)

(F,M)=(1,0)

(F,M)=(1,1)

(F,M)=(0,0)

experiments performed with hydrogen atoms under field free conditions

High Field Seekers

Low Field Seekers

3/25Low energy anti-hydrogen atoms

[1] A. Mohri and Y. Yamazaki, Europhys. Lett. 63 (2003) 207.[2] Y. Enomoto et al., Phys.Rev.Lett.105 (2010) 243401.

Anti Helmholtz configuration: HFS-states: de-focused LFS-states: focused

EXTRACTION OF A POLARIZED BEAM

RFQD

Production target3.5GeV/c ~5x 107 pbar stochastic cooling2 GeV/c stochastic cooling300MeV/c stochastic cooling & e-coolling100MeV/c(~5MeV) stochastic cooling & e-coolling　　　　　　　 ~ 107 pbar pulse from AD (~100s cycle)100keV <5 x 106 pbar with RFQD

9/25Low energy anti-proton beams (AD to RFQD)

ASACUSA extraction line

14/25How to produceASACUSA-MUSASHI experimental setup

MUSASHI trap – pbar accumulatorPositron accumulatorCUSP trapSpin flip cavitySextupole MagnetDetectors

We need antihydrogen → has to be synthesized first

In Reality

Antiprotons from AD RFQD decelerator(200 MHz, 1.1 MW, 0.5 ms)

MUSASHI

CUSP

e+

Status of the new e+ sourcee+ source1.85 Gbq (<100 keV)

Cusp trap

B = 0.3 T

B = 2.7 T

20/25

5 x 105 pbar(< 20 eV)

B = 2.5 T

Ne moderator2.3 106/s (<3 keV)

e+ trap106/15s (<3 keV)

Detection of Antihydrogen

Neutral antihydrogen escapes from trapApply field ionization well → strip positron, catch pbar.Release field ionization well

Result after releaseNo peak without positronsClear indication for production of antihydrogen.Downstream detector: hbar candidate signals detected.

19/25

6 x 10 e+/ 60 shot, ~0.01eV

6

~ 150eV e+ pulse

~ 150eV pulse

Cusp trap

H produced !

201 Direct Injection ( of p) scheme

Potential

• Axial Frequency Scaling

Exciting the particles as by a swept rf with a certain stop frequency:

Definition of interaction energy

How to improve on the F.I. signal ? A.R.

Insert slide AR

+Figuur Kuroda-san.

Prepare 40 million positrons in the nestedInject directly from MUSASHI trapApply RF during interaction

RF Assisted Direct Injection

Produced encouraging results – further evaluation in progress

Frequency Scaling in Nested Well

12/25

CjLjRcjljr

Z

nnn

11

/1

11

)(

30

35

40

45

50

10.4 10.6 10.8 11.0 11.2

po

wer

(d

B)

frequency(MHz)

Q ~ 100 (f ~ 100 kHz)

30

35

40

45

50

10.4 10.6 10.8 11.0 11.2

po

wer

(d

B)

frequency(MHz)

Q ~ 100 (f ~ 100 kHz)

0.0

1.0

2.0

3.0

4.0

0 100 200 300 400 500N

e f (kHz)

x 10 8

2)( fn

0

12

2z

Vedzmzmzm z

irdticdt

dilV s

ss

12

12

20

20

2

21

2

21

2

20 4

,4

,4

de

mzr

zm

dec

de

mzl s

zss

nrrnccnllinI snsnsn /,,/, 0

1

2z

dzei

oddkk

k

k Pz

rd )(cos

2

1

0

[11] X.Feng, M.Charlton, M.Holtzscheiter, et al., J. Appl. Phys.79, 8 (1996)

Low energy antiproton beam (Tank circuit signal)

13/25

0

2

4

6

8

10

12

14

0.0 0.5 1.0 1.5 2.0

Np

bar

f (kHz)

x10 6

(d)

How to produce (Low energy antiproton beam)Tank circuit signal with 3AD shot accumulated in MUSASHI

H

Summary

Production of antihydrogen demonstrated. Candidate signals for extracted hbar at downstream detector. Applying Continuous rf incread the Hbar formation rate by ~factor 4. Major step towards first antihydrogen hyperfine spectroscopy.

Analysis of 2012 data is ongoing and results will be presented soon !

Thank you for your attention

Antiproton trapPositron trapCUSP trapHbar detectorCUSP detectorsSMI cavity +sextupole + hodoscope

The chief

Backup slides

Spectroscopy

Correction: QED and proton/antiproton structure – level 10-6.Together with high precision proton g-factor measurement: constraints on antiproton structure

We aim at 10-6 or better.

1.420 405 751 766 7(9) GHz

Proposals to measure more precisely

Far Future !

3 x 10 pbar(< 20 eV)

5

18/25

6 x 10 positron(<0.1eV, ne+~108cm-3)

6

CERN PS (3.5GeV/c, 5 x 10 )AD (5MeV, 10 )RFQD (100keV, 5 x 10 )MUSASHI (150eV, 5 x 10 )

7

6

5

7

27mCi Na (<100keV, ~109 /s)W moderator, N2buffer gas

(<3 eV, ~106 /s)Pre-accumulator (130eV, 2 x 105 /30s)

22

positron

antiproton (pbar)CUSP trap

How to produce Specifications

RFQD

Production target3.5GeV/c ~5x 107 pbar stochastic cooling2 GeV/c stochastic cooling300MeV/c stochastic cooling & e-coolling100MeV/c(~5MeV) stochastic cooling & e-coolling　　　　　　　 ~ 107 pbar pulse from AD (~100s cycle)100keV <5 x 106 pbar with RFQD

9/25Low energy anti-proton beams (AD to RFQD)

ASACUSA extraction line