1. 7/3/2016Milano Consiglio di Sezione AEGIS: a moirè deflectometer for antimatter Marco G. Giammarchi Istituto Nazionale Fisica Nucleare - Milano A E g I SA E g I S Antimatter Experiment Gravity Interferometry Spectroscopy AEGIS: AD-6 Experiment at CERN – Geneva (CH) http://aegis.web.cern.ch/aegis/ AEGIS : antimatter gravity measurement Antiprotons delivered in 2012 Mini-moirè deflectometer Paper accepted Nature Communications http://aegismilano.wordpress.com/

2. 7/3/2016Milano Consiglio di Sezione S. Aghion et al., Prospects for measuring the gravitational free-fall of antihydrogen with emulsion detectors, JINST 8 (2013) P08013. S. Aghion et al., Detection of low energy antiproton annihilations in a segmented silicon detector, JINST 9 (2014) P06020 S. Aghion et al., A moirè deflectometer for antimatter, accepted by Nature Communications 2013/2014 publications: J. Storey et al., Particle tracking at 4K: The Fast Annihilation Cryogenic Tracking (FACT) detector for the AEgIS antimatter gravity experiment, Nuclear Instr. & Methods A732 (2013) 437. M. Kimura et al., Development of nuclear emulsions with 1 μm spatial resolution for the AEgIS experiment, Nuclear Instr & Methods A732 (2013) Journal Articles M. Giammarchi, AEgIS at CERN: measuring antihydrogen fall. QFTHEP2013, XXIth International Workshop on High Eenergy Physics and Quantum Field Theory, St Petersburg (Russia), June 2013. S. Aghion, Development of nuclear emulsions with 1 μm spatial resolution for the AEgIS experiment, Swansea M. Giammarchi, Study of fundamental Laws with Positronium and Antihydrogen, FisMat2013, Italian National Conference on Condensed Matter Physics. Milano, September 2013. Published Proceedings Milano Speaker

3. 7/3/2016 AD beam 22 Na e + source Surko trap & accumulator p trap mixing chamber Moiré deflectometer FisMat 2013

4. 7/3/2016Milano Consiglio di Sezione Precise measurement of forces : insight into fundamental interactions In the context of neutral antimatter  Gravitational studies Weak Equivalence Principle violation ? The Physics Motivation An atom optical tool : the moirè deflectometer Slow antiprotons Measurement of deflection with slow antiprotons The Technology General idea

5. 7/3/2016FisMat 2013 One step back: Antihydrogen fall and detection in AEGIS DISPLACEMENT DUE TO GRAVITY IS IMPOSSIBLE TO DETECT IN THIS WAY BUT: - antihydrogen has a radial velocity (related to the temperature) - any anti-atom falls by 20 μm, but, in addition it can go up or down by few cm - beam radial size after 1 m flight ~ several cm (poor beam collimation) AEgIS realistic numbers: - horizontal flight path L ~ 1 m - horizontal velocity v z ~ 500 m/s vertical deflection ~ 20 μm

6. FisMat 2013 Now displacement easily detectable. At the price of a huge loss in acceptance cm Let us collimate! Position sensitive detector Acceptance can be increased by having several holes. In doing so new possible paths show up cm Let us collimate! L1L1 L2L2 If L 1 = L 2 the new paths add up to the previous information on the 3 rd plane 7/3/2016 100 μm slit

7. FisMat 2013 Based on a totally geometric principle, the device is insensitive to a bad collimation of the incoming beam (which however will affect its acceptance) Moiré Deflectometry is an interferometry technique, in which the object to be tested (either phase object or secular surface) is mounted in the course of a collimated beam followed by a pair of transmission gratings placed at a distance from each other. The resulting fringe pattern, i.e., the moiré deflectogram, is a map of ray deflections corresponding to the optical properties of the inspected object.interferometrycollimatedfringe 7/3/2016 L L

8. Milano Consiglio di Sezione Our work with antiprotons in 2012 with a prototype of the moirè deflectometer Two identical transmission gratings followed by a nuclear emulsion detector Absolute referencing of the observed antimatter pattern

9. 7/3/2016Milano Consiglio di Sezione Fringes shift generated by gravity : Reference pattern obtained by light: Talbot-Laue interferometry (rephasing of light pattern at discrete distances after the grating) The AEGIS antiproton beam had a mean energy of 106 keV  a de Broglie wavelength of 8.8x10 -14 m, a “particle” beam in our case The annihilation positions of antiprotons after the two gratings are measured in the emusion detector (6.5 hr exposure). After exposure, the emulsion is developed and analysed. The reference light pattern (640 nm, 5.th Talbot revival) is measured with a high- resolution ccd scanner)

10. 7/3/2016Milano Consiglio di Sezione To establish a common reference point between the particle and the light illumination, a contact grating is used Antiproton annihilation in emulsion Normal vs Contact

11. 7/3/2016Milano Consiglio di Sezione Deflection measurement An absolute force was acting on antiprotons during the run, so that the moirè pattern got shifted with respect to the contact pattern. Light intensity is red in the figure.

12. 7/3/2016Milano Consiglio di Sezione The combination of these techniques from high-energy and atomic physics opens a very promising route to the first detection of the gravitational acceleration of neutral antimatter Observation consistent with a mean force of 540 aN = 540 x 10 -18 N acting on antiprotons Deflection measured

13. 7/3/2016Milano Consiglio di Sezione