1st Year

ANNUAL PROGRESS REPORT

 
EU_Logo

TMR - NETWORK 

 EU_Logo

 PERFECT CRYSTAL NEUTRON OPTICS

("PECNO")

ERB-FMRX-CT96-0057

  Wien, April 1998


  1. Atominstitut der Österreichischen 
      Universitäten, ATI, Wien(AT) 
  2. Institut Laue Langevin, ILL, Grenoble (FR) 
  3. Forschungszentrum Jülich GmbH, KFA (DE) 
  4. Paul Scherrer Institut, PSI, Villigen (CH) 
  5. Universita di Bari (IT) 
  6. Hahn-Meitner Institut, HMI (DE) 
  7. Universität Dortmund (DE) 
  8. Universität Innsbruck (AT) 
  9. Wacker Siltronic AG, Burghausen (DE) 
10. Central Laboratory for the Research 
      Councils, ISIS, Chilton (UK) 
11. Nuclear Physics Institute of the Academy 
      of sciences ot the Czech Republic, 
      NPI, Rez (CZ) 
12. Palacky University Olomouc (CZ) 
13. Research Institute for Solid State Physics 
      of the Hungarian Academy of Sciences, 
      RISSP, Budapest (HU) 		 a) Perfect crystal small-angle scattering cameras 
b) Gradient and multiple crystals 
c) Neutron interferometry 
d) Perfect crystal storage (resonator) system 
e) Vibrating crystals 
f) Bragg focusing and wave propagation in crystals 
g) Quantum physics consequences 
h) Crystal characterization, fabrication and testing 
i) Phase space manipulation 
j) Standing neutron waves

 

1. Scientific activities

Quantum optics in general and matter-wave quantum optics has become a very topical field in research. The network activities and plans fit also into the recent development of new neutron sources in Europe and the general trend of upgrading neutron instrumentation. In the reporting period several cooperative projects have been continued and some have been newly started on a broader basis. Some of these activities should be mentioned in this summary report. Details can be found in the appendix where the individual reports from the Network partners are collected.

a) Neutron interferometry

The upgrading of the neutron interferometer and perfect crystal small-angle scattering set-ups at ILL Grenoble were the main activities. A complete renewal of the interferometer set-up S18 instrument has been undertaken (G. KROUPA, G. BRUCKNER, H. RAUCH, G. BADUREK, M. ZAWISKY). The main new features are : (i) adaption of a third axis for various postselection experiments, (ii) use of split channel-cut crystals for the perfect crystal small-angle scattering option (to reduce the tails of the resolution function), (iii) complete renewal of the electronic and computer control system of the instrument, (iv) implementation of a new nondispersive method for precise neutron scattering length measurements, and (v) adaption of a complete polarization analyzing system (Fig. 1).
Cooperation: ATI-Wien, ILL-Grenoble, HMI-Berlin, KFA-Jülich.
The tests of split channel-cut crystals for the small-angle scattering camera and of permanent prism magnets for the production of polarized neutrons have been performed at the 250 kW TRIGA-reactor in Wien (M. HAINBUCHNER, M. VILLA, R.J. BUCHELT, G. BADUREK, H. RAUCH). Another pair of such crystals will be prepared for use at KFA-Jülich (D: SCHWAHN). The very tricky new method for very precise (better than 10-4) nondispersive scattering length measurements has been developed at the HMI-reactor in Berlin (IOFFE et al. 1997; see Fig. 2) and will be adapated to the ILL set-up as well. The new set-up will be available for routine application starting summer 1998.
Cooperation: ATI-Wien, KFA-Jülich, HMI-Berlin.
 

b) Progress in the perfect crystal neutron storage system at ISIS (Rutherford Lab.)

A fast mechanical shutter has been installed in front of the perfect crystal storage system which cuts the following bursts from the source and improves the background conditions considerably (M. JÄKEL, E. JERICHA, D. SCHWAB, C.J. CARLILE, H. RAUCH). For the first time multiple bursts (up to 6) have been stored (Fig. 3). As a next step a neutron magnetic resonance system should be added to avoid the fast switching of magnetic fields which intrinsically produces disturbing vibrations. A Q-factor of 104 seems to become feasible which means 104 traverses of the neutrons and a storage time up to 20 seconds.
Cooperation: ISIS, ATI-Wien.
 

c) Installation of a perfect crystal camera at the SINQ at PSI-Villigen

Within the frame of an official contract between ILL and PSI, the S21 optical table of the ILL has been transferred to the SINQ-spallation source. There a free beam position will be used for small-angle scattering experiments and for testing a new method for a measurement of an electric dipole moment of the neutron due to the interaction with a non-centrosymmetric crystal potential (E. JERICHA, C.M.E. ZEYEN, P. BÖNI). The planning of a rather universal optical bench for multiple beam application is in progress.
Cooperation: PSI-Villigen, ILL-Grenoble, ATI- Wien.
 

d) Theoretical matter wave quantum optics

The quantum optical formulation of neutron optical phenomena progressed substantially. The phase determination in case of weak fields (low counting rates) and various dephasing and decoherence effects have been investigated and proposals for new experiments have been made (R. MYSKA et al. 1997, Z. HRADIL 1997). The quantum Zeno-effect has been elucidated in the limit of infinitely frequent measurements where the uncertainty principle and unavoidable losses have to be considered as well (Z. HRADIL et al. 1998).
Cooperation: Uni-Bari, Uni-Olomouc, ATI-Wien.
 

 e) Perfect crystal technology

A topical Workshop "Crystals" was organized at Franking (Austria), 11-12 Dec. 1997, to discuss the future demands on perfect crystals for interferometry, topography and advanced neutron and X-ray beam tailoring. Eleven participants attended the workshop. The discussions with the industrial partner of the Network (Wacker Siltronic, W. ZULEHNER) where very useful. Minutes of the meeting are available (E. SEIDL 1998). In the availability of new crystals lies the key for further progress in these fields.
Cooperation: Wacker-Siltronic, Uni-Dortmund, HMI-Berlin, ATI-Wien, NPI-Rez, ILL-Grenoble.
 

f) Bragg diffraction optics

Gradient-, bent- or vibrating perfect or nearly perfect crystals are being developed as powerful tools for a more effective use of the neutron intensities available at stationary and pulsed sources. Impressive results have been achieved by several Network partners (MIKULA et al. 1997a, 1997b, VRANA et al. 1997, TREIMER et al. 1997).
 
 

2. Mobility issue

The Network started somewhat delayed partly due to money bank transfer problems and due to delays in the exchange of the Contracts of Association. Therefore, only small amounts from "Personnel Costs - Cat. A" have been used. The only exchange of a young researcher happened between ATI-Wien and PSI-Villigen:

Dr. E. JERICHA (post-doc), Austrian, 33 at time of appointment from July 1997 until end of 1999; experimental neutron physicist.

In 1998 we plan to intensify the search for young researchers working in the Network. Under "Networking Costs" an intense exchange program happened (seconded staff) mainly between:
 

More details can be found in the cost statements of each participant. After EU-approval several network participants presented their results outside Europe at the Int. Conf. Neutron Scattering, Toronto, 17-21 August 1997 and Symp. Material Research Using Cold Neutrons at Pulsed Neutron Sources, Argonne, 25-26 August 1997.

The manpower involved but paid by other sources corresponds to about half of the proposed manpower mentioned in the contract. This is caused by the delayed start and will change this year towards the scheduled values.
 

3. Summary

The network started delayed but got momentum later in the first year. It can be expected that in the second year essential progress can be made because most of the preparatory steps for the cooperative projects have been set. The network needs young researchers mainly with high skills in experimental and applied research which are rather rare on the market. The achievements obtained in the first year are described in chapter 1. The publications raised by the Network involving two or more participants are listed below.
 

4. References

The following publications have been produced in the frame of the Network:
  The next Workshop of the Network will take place in Rez near Prague, 25-27 June 1998.
 
 
Wien, April 1998
Helmut Rauch 
(Network Coordinator)