efficient rydberg positronium laser excitation for antihydrogen production in a magnetic field l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Efficient Rydberg positronium laser excitation for antihydrogen production in a magnetic field PowerPoint Presentation
Download Presentation
Efficient Rydberg positronium laser excitation for antihydrogen production in a magnetic field

Loading in 2 Seconds...

play fullscreen
1 / 13

Efficient Rydberg positronium laser excitation for antihydrogen production in a magnetic field - PowerPoint PPT Presentation


  • 128 Views
  • Uploaded on

Efficient Rydberg positronium laser excitation for antihydrogen production in a magnetic field. S. Cialdi, F. Castelli, I. Boscolo, F. Villa Dept. of Physics, Milano University. Marco G. Giammarchi * Istituto Nazionale Fisica Nucleare - Milano. D. Comparat

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Efficient Rydberg positronium laser excitation for antihydrogen production in a magnetic field' - grant


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
efficient rydberg positronium laser excitation for antihydrogen production in a magnetic field

Efficient Rydberg positronium laser excitation for antihydrogen production in a magnetic field

S. Cialdi, F. Castelli, I. Boscolo, F. Villa

Dept. of Physics, Milano University

Marco G. Giammarchi*

Istituto Nazionale Fisica Nucleare - Milano

D. Comparat

Lab. Aimé Cotton – CNRS Univ. Paris Sud, Orsay

In the frame of the antimatter AEGIS experiment at CERN

LEAP08 Conference Vienna, September 2008

slide2

Moire’ deflectometer and detector

AEGIS experimental strategy

1) Produce ultracold antiprotons (100 mK)

2) Accumulate e+

3) Form Ps by interaction of e+ with a porous target

4) Laser excite Ps to get Rydberg Ps

5) Form Rydberg cold (100 mK) antihydrogen by

6) Form a beam using an inhomogeneous electric field to accelerate the Rydberg antihydrogen

7) The beam flies toward the deflectometer and introduces a spatial modulation in the distribution of the Hbar arriving on the detector

8) Extract g from this modulated distribution

Cold antiprotons

Porous target

e+

LEAP08 Conference Vienna, September 2008

slide3

Ps excitation

  • Motivations:
  • Cross section
  • Final state distribution better defined
  • Conditions:
  • 1 mm Ø beam spot
  • 100 K temperature
  • 1 T Magnetic Field

Ps Excitation

Laser Light

1 n

Target

e+ Bunch

Ps*

AD

LEAP08 Conference Vienna, September 2008

slide4

Ps excitation scheme: two laser pulses

1 3

n

205 nm

3

2

3 15- 30

1

1700 – 1600 nm

good

better

3 ns lifetime for n=2 (and the overall path requires mores energy)

11 ns lifetime for n=3

n

Two simultaneous laser pulses: 1

3

Duration of pulses will be ~ 5 ns and since

The excitations will be incoherent

LEAP08 Conference Vienna, September 2008

laser system
Laser system

205 nm

2w

3w

2w

200 mJ >> 16 μJ

Nd:YAG (1064nm)

200 mJ, 4 ns

Dye- prisms

Dl > 0.05 nm

180 mJ

1700 – 1600 nm

20 mJ

OPG + OPA

1 mJ >> 174 mJ

Dl = 3 nm

Down-conversion generated and amplified

20 mJ

OPG

PPLN 4cm

Generated

Saturation

OPA

10 mJ

LiNb03

LEAP08 Conference Vienna, September 2008

the 1

3 transition

The 1

Doppler linewidth:

Motional Stark effect:

Width of the transition dominated by Doppler broadening.

Laser linewidth of the first transition designed to be 0.05 nm.

Saturation fluence calculated with rate equation model and taking into account 30 ns of free expansion of the Positronium cloud

LEAP08 Conference Vienna, September 2008

the 3

n transition

The 3

Doppler broadening: negligible

Motional Stark effect mixes (n,m,l) levels starting from n = 16

Ionization effects set in at n = 27

Ionization limit for lowest –lying sublevel

Energy distance between unperturbed n states

  • Final n should be between 15 to 30
  • Energy levels will overlap

Stark broadening

Doppler broadening

LEAP08 Conference Vienna, September 2008

slide8

Using a laser bandwidth

Δ

ΔES

We have predicted the incoherent excitation probability as:

The degenerate high-n levels become n2 manifolds with a complete mixing of their l,m substates.

laser power spectrum

sublevel density ~ n5

Interleaving of states with different n will occur

absorption coefficient ~1/n5

Saturation Fluence: 174 μJ

LEAP08 Conference Vienna, September 2008

slide9

Simulation of the level population as a function of time during a single realization of incoherent excitation.

The phase is being randomized to account for the incoherence of the pulse

Global efficiency around 30%

LEAP08 Conference Vienna, September 2008

laser system10
Laser system

205 nm

2w

3w

2w

200 mJ >> 16 μJ

Nd:YAG (1064nm)

200 mJ, 4 ns

Dye- prisms

Dl > 0.05 nm

180 mJ

1700 – 1600 nm

20 mJ

OPG + OPA

1 mJ >> 174 mJ

Dl = 3 nm

Down-conversion generated and amplified

20 mJ

OPG

PPLN 4cm

Generated

Saturation

OPA

10 mJ

LiNb03

LEAP08 Conference Vienna, September 2008

slide12

LASER

OPA

Filtro Spaziale

OPG

LEAP08 Conference Vienna, September 2008

experimentally
Experimentally........
  • The first excitation can be performed with a commercial laser.
  • We have focused our attention on the second one, the OPG/OPA system.
  • The OPG part has been succesfully tested. The expected energy has been obtained (with the required safety factor) and the expected frequency bandwidth
  • Now we are testing the OPA system (and this is the CONCLUSION)

LEAP08 Conference Vienna, September 2008