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Univ. Prof. Dr. Hartmut Abele

Tel.: +43-1-58801-141202 
Fax: +43-1-58801-14199

TU Wien - Atominstitut
Stadionallee 2
1020 Wien




FWF project I 530-N20 „Gravitational induced phases in neutron interferometry"

Large crystal neutron interferometer measurements

New interferometer:

The largest perfect crystal neutron interferometer (30x12 cm) has been fabricated with our co-operation partner at the Physikalisch Technische Bundesanstalt (PTB). The 15 mm thick sample blades can be used for a high angular resolution measurement.

New IFM together with the first Si perfect crystal interferometer


M. Zawisky, J. Springer, H. Lemmel: 
“High angular resolution neutron interferometry” 
Nucl. Instr. Methods A634 (2011) p.46-49

Chameleon experiment:

We search for phase shifts associated with a coupling to scalar fields. We set stringent limits for a scalar chameleon field, a prominent quintessence dark energy candidate, and we found that the the coupling constant ß is less than 1.9 ×10^7 (for Ratra-Peebles index n = 1) at 95% confidence level.

Neutron interferometer with a vacuum chamber. The chameleon phase profile between the chamber walls is shown as well


H. Lemmel, Ph. Brax, A. N. Ivanov, T. Jenke, G. Pignol, M. Pitschmann, T. Potocar, M. Wellenzohn, M. Zawisky, H. Abele, 
Neutron interferometry constrains dark energy chameleon fields, 
Physics Letters B (2015)

Laue phase:

In this study, we investigate the phase shift induced by Laue transmission in a perfect Si crystal blade in detail. This 'Laue phase' was measured at two wavelengths in the vicinity of the Bragg condition within a neutron interferometer. A fascinating steep phase slope of 5.5° ((220) Bragg peak) and 11.5° ((440) Bragg peak) per 0.001 arcsec deviation from the Bragg angle has been achieved. 

Laue phase for the (220) case


T. Potocar, M. Zawisky, H. Lemmel, J. Springer and M. Suda,
Neutron interferometric measurement and calculations of a phase shift induced by Laue transmission, 
Acta Cryst. A71 (2015)

We thank the Austrian Science Fund (FWF, Proj. No. I530-N20) and CENI, Central European Neutron Initiative, as well as the Collaboration Agreement between ILL and TU-Wien (ILL-1132.1-3) for financial support.