QUPLAS (QUantum interferometry and gravity with Positrons and LASers)

Authors of this work: S. Sala, A. Ariga, A. Ereditato, R. Ferragut, M. Giammarchi, M. Leone, C. Pistillo and P. Scampoli
   Brief description of this work

The scientific goal of the QUPLAS (QUantum interferometry and gravity with Positrons and LASers) antimatter experiment is the opening of two new fields of investigation in modern particle physics: antimatter interferometry, using both an elementary antiparticle (the positron, e+) and a bound e+/e- state (positronium, Ps), to test the validity of the fundamental CPT symmetry, and gravitation studies with positronium, an innovative way to inspect the Weak Equivalence Principle with a particle/antiparticle symmetric system.

Video di YouTube

The first stage of the experiment aims at the comparison of positrons and electrons interference, to compare for the first time the quantum interferometry pattern of a particle with the one of its own antiparticle. To achieve this goal, a dedicated interferometer is being assembled at the VEPAS (Variable Energy Positron Annihilation Spectroscopy) positron beamline located at the L-NESS (Laboratory for Nanostructure Epitaxy and Spintronics on Silicon) Laboratory of the Politecnico di Milano in Como (Italy).

Animation based on actual data

         Simone Sala

          Rafael Ferragut and Marco Leone        

Experimental set-up


ematics of the Talbot-Lau interferometer
Antonio Ereditato

Paola Scampoli

 Ciro Pistillo and Marco Giammarchi

https://sites.google.com/site/fotosquplas/ESF_QUPLAS_r.jpg?attredirects=0Elena Tonello, Stefano Aghion and Francesco Barantani (2016)

One of the gratings that are used in the QUPLAS experiment for positron interferometer

Contrast on the emulsion surface

https://sites.google.com/site/fotosquplas/foto1%20%282%29.jpg?attredirects=0Partial view of the positron interferometer

Aki Ariga and Ciro Pistillo

Micrograph of the emulsion containing the open regions of one of the gratings.
The periodicity of the positrons signal is clearly visible 
(see Aghion et al. JINST 13, P05013 (2018)

Contrast as a function of energy

A continuous positron beam is used to produce Talbot-Lau interference by means of micrometric gratings. The particle detection relies on the employment of emulsion based high-precision position detectors, which are being developed by the physicists of the Bern group in QUPLAS. Pictures of the first interferometer prototype and the micrometric gratings are presented in this page.
An intensive R&D program has been conducted by the whole collaboration to assess the detectability of very low energy particles with emulsions and the capability to detect positrons at the keV energy scale has been successfully demonstrated.

1) Vacuum chamber containing the interferometer and the mu-metal shield. 2) Vacuum system. 3) x-y stage moving the absorbing target for beam size measurement. 4) Viewport for laser alignment. 5) BaF2 detector. 6) Beam control electronics. 7) Bellows used for the alignment of the interferometer chamber.

QUPLAS Spokesperson: M.Giammarchi, INFN Milano

More details available in these articles:
  1. S. Sala, F. Castelli, M. Giammarchi, S. Siccardi, S. Olivares. Matter-wave interferometry: towards antimatter interferometers. J. Phys. B: At. Mol. Opt. Phys. 48, 195002 (2015) doi: 10.1088/0953-4075/48/19/195002 pdf
  2. S. Sala, M. Giammarchi, S. Olivares. Asymmetric Talbot-Lau interferometry for inertial sensing. Phys. Rev. A 94, 033625 (2016) doi: 10.1103/PhysRevA.94.033625 pdf
  3. S. Aghion, A. Ariga, T. Ariga, M. Bollani, E. Dei Cas, A. Ereditato, C. Evans, R. Ferragut, M. Giammarchi, C. Pistillo, M. Romé, S. Sala, and P. Scampoli. Detection of low energy antimatter with emulsions. JINST 11 P06017 (2016) doi: 10.1088/1748-0221/11/06/P06017 pdf
  4. S. Aghion, A. Ariga, M. Bollani, A. Ereditato, R. Ferragut, M. Giammarchi, M. Lodari, C. Pistillo, S. Sala, P. Scampoli, and M. Vladymyrov. Nuclear emulsions for the detection of micrometric-scale fringe patterns: an application to positron interferometryJINST 13, P05013 (2018) doi: 10.1088/1748-0221/13/05/P05013  pdf
  5. S. Sala, A. Ariga, A. Ereditato, R. Ferragut, M. Giammarchi, M. Leone, C. Pistillo, P. Scampoli. First demonstration of antimatter wave interferometryScience Adv. (I.F.: 11.515 eaav7610 (2019) doi: 10.1126/sciadv.aav7610  pdf
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