positron lab – Como

01.02.25: M. Sacerdoti, V. Toso, G. Vinelli, M. Bayo, G. Rosi, L. Salvi, G. M. Tino, M. Giammarchi, R. Ferragut. Monte Carlo simulations towards the formation of a positronium coherent beam. Nucl. Instrum. Methods Phys. Res. A, 1071, 170068 (2025). doi: 10.1016/j.nima.2024.170068 pdf

27.12.23: F. Castelli, S. Cialdi, G. Costantini, R. Ferragut, M. Giammarchi, G. Gittini, M. Leone, G. Maero, S. Olivares, M. Romé, A. Simonetto, V. Toso. Loss and revival of coherence in the interaction between a positron beam and a photon field. Journal of Plasma Physics, 89(6) 935890603 (2023). doi: 10.1017/S0022377823001319 pdf

29.09.23: G. Vinelli, F. Castelli, R. Ferragut, M. Romé, M. Sacerdoti, L. Salvi, V. Toso, M. Giammarchi, G. Rosi, G. M. Tino. A large-momentum-transfer matter-wave interferometer to measure the effect of gravity on positronium. Class. Quantum Grav. 40 205024 (2023) doi: 10.1088/1361-6382/acf8ab pdf

08.07.21: E. Pasino, S. Cialdi, G. Costantini, R. Ferragut, M. Giammarchi, S. Migliorati, M. Romé, T. Savas, V. Toso, An Interferometric Method for Particle Mass Measurements, Symmetry 13, 1232 (2021) doi: 10.3390/sym13071232 pdf

23.11.20: G. Vinelli, R. Ferragut, M. Giammarchi, G. Maero, M. Romé, V. Toso. Real-time monitoring of a positron beam using a microchannel plate in single-particle mode, JINST 15, P11030 (2020) doi: 10.1088/1748-0221/15/11/P11030 pdf 

26.03.20: L. Anzi, A. Ariga, A. Ereditato, R. Ferragut, M. Giammarchi, G. Maero, C. Pistillo, M. Romé, P. Scampoli, V. Toso. Sensitivity of emulsion detectors to low energy positrons, JINST 15, P03027 (2020) doi: 10.1088/1748-0221/15/03/P03027 pdf

21.01.20: A.Ariga, S.Cialdi, G.Costantini, A.Ereditato, R.Ferragut, M.Giammarchi, M.Leone, G.Maero, L.Miramonti, C.Pistillo, M.Romé, S.Sala, P.Scampoli, V.Toso, The QUPLAS experimental apparatus for antimatter interferometry, Nucl. Instrum. Methods Phys. Res. A 951, 163019 (2020) doi: 10.1016/j.nima.2019.163019 pdf

04.12.19:  The antimatter interferometry experiment performed in our laboratory is one of the Top 10 Breakthrough 2019 (physicsword).

03.05.19:  First demonstration of antimatter wave interferometry by S. Sala, A. Ariga, A. Ereditato, R. Ferragut, M. Giammarchi, M. Leone, C. Pistillo and P. Scampoli

Brief description of this work: Italian (breve descrizione in italiano)
Spanish (breve descripción en castellano)

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.

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).

Simone Sala

   Rafael Ferragut and Marco Leone

Experimental set-up

Ciro Pistillo and Marco Giammarchi

Elena Tonello, Stefano Aghion and Francesco Barantani (2016)

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

Micrograph of the emulsion containing the open regions of one of the gratings.

Partial view of the positron interferometer: 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.

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.

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 interferometry, JINST 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 interferometry, Science Adv. (I.F.: 12.804) 5eaav7610 (2019) doi: 10.1126/sciadv.aav7610  pdf
6. L. Anzi, A. Ariga, A. Ereditato, R. Ferragut, M. Giammarchi, G. Maero, C. Pistillo, M. Romé, P. Scampoli, V. Toso. Sensitivity of emulsion detectors to low energy positrons, JINST 15, P03027 (2020) doi: 10.1088/1748-0221/15/03/P03027 pdf
7. A.Ariga, S.Cialdi, G.Costantini, A.Ereditato, R.Ferragut, M.Giammarchi, M.Leone, G.Maero, L.Miramonti, C.Pistillo, M.Romé, S.Sala, P.Scampoli, V.Toso, The QUPLAS experimental apparatus for antimatter interferometry, Nucl. Instrum. Methods Phys. Res. A 951, 163019 (2020) doi: 10.1016/j.nima.2019.163019 pdf

More information: some presentations

• M. Giammarchi et al. (QUPLAS) Bern 2016
• S. Aghion et al. (QUPLAS) Messina 2016
• S. Sala et al. (QUPLAS) Milan 2017
• M. Giammarchi, Progress on Antimatter Interferometry (Workshop on Lorentz and CPT-violating Standard Model Extension – Indiana University) Indiana, June 2018
• M. Giammarchi et al. (QUPLAS) First Observation of Antimatter wave interference (Quantum SFB Vienna Meeting) Vienna 2018
• R. Ferragut et al. (QUPLAS) Antimatter Interferometry (International Conference on Positron Annihilation – ICPA-18), Orlando 2018
• S. Sala et al. (QUPLAS) QUPLAS: towards antimatter interferometry (Frontiers Of Matter-wave Optics: FOMO 2018) Crete, 2018

PhD Thesis: Simone Sala: QUPLAS: TOWARDS ANTIMATTER INTERFEROMETRY