Scientific Coordination Office (SCO)
6, rue Jules Horowitz, BP 156, F-38042 Grenoble Cedex 9, France
ILL RESEARCH PROPOSAL
(please read the attached guidelines before submitting the completed proposal form to the above address)
Experiment title:Depolarization of Stored UCN in Diamond Coated Vessels / Proposal number
(to be completed by ILL)
Proposer(to whom correspondence will be addressed)
Name and first name: Axel Pichlmaier
Address: Los Alamos National Laboratory
Group P-23, MS H803
Los Alamos, NM 87544, USA / Phone: +1 505 665 0435
Fax: +1 505 665 4121
Email:
New neutron user? [ ] Yes [X] No
New ILL user? [ ] Yes [X] No
Co-proposers: ( mark with an asterisk the main proposer in each laboratory)
Name and first name: Address (if different from above):
Thomas J. Bowles, LANL, Los Alamos, NM, USA 87545
Alexander Saunders, LANL, Los Alamos, NM, USA 87545
Albert Young*, NC-State Univ. NC, USA 27695
Mark Makela*, Verginia Tech, Blacksburg, VA, USA 24061
Anatoli Serebrov*, PNPI Gatchina, Russia
Masahiro Hino*, Kyoto University, Japan / Phone/fax/email
Local contact(s): / Peter Geltenbort/James Butterworth
Suggested keyword number (see guidelines for details): 3-14
This proposal is:
[X] A new proposal (Please attach copy of report(s) on your recent experiments on related topics).
[ ] A continuation proposal, an application for further beam-time must be supported by a report on the previous measurements. Please attach copies of your experimental report (on an official report form).
[ ] A resubmission, please give previous proposal number :______
Indicate the main research area of your proposal - tick only one box ( for statistical purposes only ):
[ ] Biology [ ] Chemistry [X] Physics [ ] Materials [ ] Methods and instrumentation
[ ] Engineering [ ] Soft condensed matter [ ] Other: ______
Indicate if your proposal is related to industrial application ( for statistical purposes only ):
[ ] Related to industrial applications, please indicate if collaboration with industry exists :______
Instrument requiredPF2-UCN-testbeam / Estimated measuring time
3 weeks / Requested starting time:
1. Jan/Feb___ 2. Mar/Apr___ 3. May/Jun___
4. Jul/Aug_X_ 5. Sep/Oct_X_ 6. Nov/Dec___
unacceptable dates:
When will the sample be available (please give details) ?______
I certify that the details on the proposal form are complete and correct.Date : Signature of proposer:
Itisessentialtocompletethispage. Missinginformationcandelay
the safety assessment and result in a rejection of the proposal.
sample description(if there is insufficient space, please include details in main text of the proposal)
Substance/Formula (give isotopic composition if not natural):
Does not apply
Mass (in mg): Size(in mm3): Surface area:
[ ] Powder [ ] Liquid [ ] Gas [ ] Polycrystalline [ ] Single crystal Others :
To be specified as appropriate for scientific evaluation :
Space group (if known):
Unit cell dimensions at T= : a = b = c =
Sample container (cylinder, flat plate, pressure cell, etc.):
safety aspects: Is the sample
[ ] Radioactive?[ ] A contaminant?[ ] Toxic?[ ] Inflammable?
[ ] An -emitter?[ ] Corrosive?[ ] A biological hazard?[ ] Explosive?
Is there any danger associated with the proposed sample or its preparation at ILL?
[ ] Yes [ ] Uncertain [X] No If yes or uncertain, please give details of the risks associated:
Is the sample a transuranium sample? [ ] Yes [ ] No
experimental details
Energy/wavelength range: neV Resolution in energy or wavelength:
Range of momentum transfer: Resolution in momentum transfer:
sample environment equipment (supplied by ILL)
[ ] Ambient [ ] Closed-cycle refrigerator [ ] 4-circle cryostat [ ] Dilution fridge
[ ] 4-circle dilution [ ] Cryostat [ ] Cryoloop N2 [ ] Cryofurnace
[ ] Furnace [ ] High pressure [X] Magnet [ ] Horiz. cryomagnet
[ ] Vert. cryomagnet [X] Nuclear physics [X] Supplied by the user
[ ] Others:
Temperature range : room temperature Pressure range: vacuum 10-6 mbar
Magnetic-field strength (stability) : 4.5 T
Is there any danger associated with ancillary equipment?
[ ] Yes [ ] Uncertain [X] No If yes or uncertain, please give details of the risks associated:
Give details of special material or equipment supplied by user, in the technical form
Superconducting magnet, neutron guides (stainless steel and quartz), shuttes, vacuum equipment, 3He detector
To be filled in by ILL
Sample environment code / Comments by Health Physics Officer and Safety Engineer / N° of days allocated
scientific background and detailed description of the proposed experiment , see also guidelines attached
(please respect the available space)
Abstract (~ 100 words):Studies of the depolarization of UCN stored in material traps are important for a number of reasons. A better understanding of the depolarization of UCN during the storage could help to shed light on the long standing problem of the so called anomalous UCN losses. It is even more important for future measurements of the correlation coefficients of the weak interaction using stored UCN. Although first experiments have been already carried out by some of us (see [1,2]) we plan to investigate in more detail the properties especially of diamond film coatings. This material is very promising for future UCN storage experiments because of its high surface potential; it also does not contain any magnetic components. A technique to make such films has also been developed by our group (M. Makela).
______
Storage of UCN is a well established and widely used technique (see, e.g.[3]), mainly for investigation of the fundamental properties of the neutron like its lifetime and its dipole moment. New applications include the investigation of angular correlations in neutron decay. However, the so-called anomalous losses and depolarization are longstanding and still not resolved issues in the understanding of the storage process. A detailed understanding of the depolarization during storage is crucial for the measurement of angular correlation coefficients for polarized neutrons. The proposed experiment is an important milestone towards the understanding of the depolarization and the success of these new types of experiments.
We propose the following set-up (see fig. 1): UCN are filled from the source through a buffer volume(velocity selector) and then a beam switch, and a polarizing magnet into a storage volume. This volume consists of a neutron guide coated with diamond-like carbon. It can be closed on both ends using diamond-coated gate valves. A holding field of 50 G in the storage volume prevents depolarization other than due to wall interactions. The velocity filter using a polyethylene absorber can be included in a buffer volume before the magnet in order to absorb UCN with higher velocity but wrong spin state that could cross the magnetic barrier and give a wrong depolarization signal if they survived the storage period in the diamond-coated guide. The energy of the UCN entering the storage trap will be defined by the position of a polyethylene absorber for the high energy cut-off and a potential barrier (by gravitation) for the lower cut-off. Both limits can be adjusted in a wide range. The UCN are stored during 10 to 50 s and then released into the detector. In detector 1 the total number of surviving neutrons can be counted whereas detector 2 permits one to count depolarized neutrons. Comparing the rates of the two detectors allows one to measure the depolarization probability during the storage period. It is also possible to flow the neutrons constantly through the diamond coated guide counting them in detector 1.
We estimate that the UCN undergo, during the storage period, wall collisions at a rate of approximately 50 s-1 for a mean free path of 10 cm and a mean velocity of 5 m s-1. Assuming a density of 10 stored UCN cm-3 we will be able to store about 5104 UCN and to accumulate 2.5107 wall interactions for a holding time in the storage volume of 10 s. Taking into account the achievable backgrounds of 1 UCN/200 s, this will give us the necessary sensitivity to probe the depolarization down to well below 10-6 per collision.
In earlier experiments it had turned out that even small magnetic contamination on or under the surface can dramatically increase the probability for depolarization. Therefore we propose to probe carbon diamond-like coatings on quartz, glass, stainless steel and steel surface. Extra care will also be taken not to introduce any magnetic contamination at the joints of the single neutron guide tubes.
The equipment we plan to use is either already at the ILL (like the superconducting magnet) or under construction and will be available in early summer this year. Standard components like the vacuum system or the UCN detectors are readily available in our laboratories.
Edition Mai 2000
Edition Mai 2000
Figure 1
[1] ILL experimental report on experiment 3-14-78
[2] A. Serebrov et al, NIM A 440 (2000) 717-721
[3]
Your publication record (give references to papers published in the last two years arising from ILL experiments):
[1] R. Hill, et. al. NIM A 440 (2000) 674-681
[2] A. Pichlmaier et al, NIM A 440 (2000) 512 - 521
Edition Mai 2000
Guidelines for the submission of a Proposal at ILL
Edition Mai 2000
Application for beam time - instructions
• You will find the ILL proposal form as a word or latex file under: WebProp using Netscape 3 or 4 or explorer 4. Paper proposal forms are still available from the Scientific Coordination Office (SCO) at the ILL . An ILL proposal form should be completed and sent to SCO.
• We strongly recommend to submit your proposals through the web. Detailed guide-lines for application for beam time via the web can be found under
• The proposal must be typewritten in English. A type-face such as "Times", 14 points with at least 1.5 line spacing is recommended because of the 70% reduction.
• Please send the original version of your proposal together with a double-sided copy in reduced form, i.e. a reduction from A3 format of the original form to A4 format. Please make the copies double-sided; i.e. one sheet per proposal. Emailed and faxed proposals are not accepted.
• Do not change the format in word-processor files.
• Please respect the available space on the form
• For accepted proposals we will send an invitation to each participating laboratory. Please indicate the names of the experimental team and make sure to include at least one experienced scientist in it.
• For a continuation proposal you must attach the report from your previous experiment. Failure to do so may lead to rejection. You can download the form as word or latex file under /SCO/ExpRep. Instructions how to submit an experimental report via the web can be found under ExpRep.
• For a "new" proposal you should attach to your proposal copies of reports on your recent experiments on related topics, so as to provide the subcommittee with maximum information.
• If you plan to come with your own experimental set-up, you can describe it in an attached "technical form". If you use the web form, you will be offered the possibility to submit a "technical form", whenever the sample environment code "Supplied by users" is selected.
• In order to find out how ILL experiments are useful for applied research we ask you to indicate if your proposal has any connection to industry. This is only for our information and has no effect on selection.
• In all cases it is important to give references to your published work where this may help the subcommittee.
• You must have an ILL staff member as a local contact, who will assist in the measurement. Please verify with your local contact whether the experimental conditions proposed are feasible. SCO will help you to find a local contact.
• Newcomers are recommended to establish contacts with experienced users. SCO will help you to find advice.
• Proposers from non-member countries have to seek collaboration with scientists from member countries. Any beam time in collaboration with a non-member country will be counted entirely for the member country.
Writing a proposal
• give a brief statement of the background and the general importance of the research.
• give a clear account of the aims of the proposed experiment and a detailed description of the experiment.
• give results of preliminary work carried out, e.g. NMR, x-rays, light scattering, etc. and the relationship with your proposed experiment.
• give the number of samples and estimate the measuring time for each sample; show how you calculate the beam-time requirements.
• state why the ILL is necessary for your experiment, especially with regard to the need of neutrons in particular.
• include a list of relevant published literature.
Checklist
Have you:
• filled in the sample description and safety aspect section?
• filled in the instrument and beam time requested?
• given the availability of sample and unacceptable dates?
• signed your proposal?
•nominated a representative from each participating laboratory?
• included a reduced double-sided copy of the signed form with the original? Is the reduced copy readable?
• included your experimental report with a reduced copy for a continuation and (if appropriate) a "new" proposal?
• given your publication record?
• informed your local contact?
Mailing address:
Institut Laue Langevin - SCO
6 rue Jules Horowitz, BP 156
F-38042 Grenoble Cedex 9, France
Deadlines for submission and scheduling
Deadlines for receipt are February 15 and August 31. Proof of posting will not be considered as a valid reason for the late arrival at the Institute and all such proposals received after the deadline will be automatically referred to the following council, 6 months later. The web system will be operational approximately two months before the dead- line for application.
There are 4.5 reactor cycles a year (one cycle is 50 days).
Accepted proposals submitted by February will receive beam time in the second half of the year and submitted by August in the first half of the next year.
After receiving the invitation (the ILL sends one invitation per laboratory) please fill it in and return it to SCO, so that you have no problems in entering the site. Visitors from non-EU countries should check visa requirements to enter France.
Note that your results should be published giving proper credit to ILL staff members and proper mention of ILL facilities.
For further details (submission of proposals, forms, schedules, reimbursement conditions, experimental reports) look on the web under or contact :
Scientific Coordination Office (SCO)
Head:Dr. Giovanna Cicognani, tel:+33 4 76 20 71 79
email: , fax: +33 4 76 48 39 06
Secretaries:Diana DijouxKatja Mayer-Jenkins
tel: +33 4 76 20 70 82+33 4 76 20 72 40
email:
Contact for guesthouse reservations:
Reception : Vera Gontier and Laetitia Rosselet
tel: +33 4 76 20 71 11, fax: +33 4 76 48 39 06
email:
Contact for travel and payment of expenses:
Travel office: tel: +33 4 76 20 73 63, fax: +33 4 76 48 39 06
email:
Edition Mai 2000
Edition December 1999
College and Keyword system for the Classification of Proposal
Edition December 1999
College 3 : Nuclear and Fundamental Physics
3-01PN1 (Lohengrin) Fission product spectrometry
3-03PN3 (GAMS) Gamma-ray spectrometry
3-07PF1 Cold (polarised) neutron beam
3-14PF2 Very cold and ultracold neutrons
3-15Other fundamental and nuclear physics
College 4 :Structural and Magnetic Excitations
4-01Lattice dynamics
- phonon dispersion relations
- phonon polarisation vectors
- anharmonic effects (frequency shifts and phonon line shapes)
4-02Dynamics of structural phase transitions
- critical scattering
- soft modes
- central peaks
- modulated phases
4-03Magnetic excitations in ordered systems
- spin waves
- Stoner excitations
- crystal-field excitations
- non-linear magnetic excitations
- magnon-phonon interaction
- collective excitations in low-dimensional systems
- nuclear magnetism (hyperfine interaction)
4-04Dynamics of magnetic phase transitions
- magnetic critical scattering
- magnetic soft modes
- linewidths and spin relaxation effects
- modulated phases
4-05Dynamics of short-range ordered and dilute magnetic systems
- dynamics of paramagnetic systems
- crystal fields in dilute systems
- magnetic impurities and clusters
- dynamics of liquid and amorphous magnetic systems
- spin glasses
College 5 :Crystallography and Magnetic Structures
College 5ACrystallography
Single-crystal diffraction
5-11Inorganic structures
5-12Organic structures
5-13Crystalline short-range order
5-14Thermal motion
5-15Structural studies of phase transitions,
superstructures, incommensurate structures, quasicrystals
5-16Special aspects of single-crystal diffraction, including:
- diffraction physics (anomalous scattering extinction, TDS, etc.)
- topography
- interferometry
Powder diffraction
5-21Small structures:
- inorganics, organics, minerals, ceramics
5-22 Large structures and defect structures
- zeolites, intercalates, catalysts, solid electrolytes, hydrides and hydrogen storage, quasicrystals
5-23 Electronic materials:
- superconductors, mixed-valence compounds, heavy-fermion compounds
5-24Structural studies of phase transitions, effects of temperature and pressure
5-25Chemical kinetics, thermo-diffractometry, thermal expansion
5-26Special applications :texture, stress, unit-cell indexing, ab-initio structure determination
College 5B :Magnetism
Powder diffraction
5-31- magnetic structure determination
- magnetic phase diagrams
5-32- magnetic defects, short-range order or
correlations
- amorphous magnets
- magnetic small-angle scattering
Single-crystal diffraction
5-41- magnetic structure determination
- magnetic structures phase diagrams
5-42- magnetic defects, short-range order or
correlations
- small-angle scattering
Polarised beam diffraction and diffraction with polarisation analysis (neutron polarimetry)
5-51- magnetisation density (including related single-crystal structure refinement)
- electronic form factors
- magnetic structure
- magnetic phase diagrams
5-52- nuclear polarisation
- depolarisation studies
5-53- magnetic defects, short-range order or correlations
- amorphous magnets
College 6 :Structure and Dynamics of
Liquids and Glasses
6-01Monatomic liquids and gases
6-02Molecular liquids and gases ( including aqueous solutions)
6-03Liquid alloys and molten salts
6-04Glass transition in polymeric glasses
6-05Glasses and amorphous materials (non-polymeric)
College 7 :Materials Science, Surfaces and Spectroscopy
7-01Metallurgy and metal physics
7-02Dynamics of H in metals
7-03Dynamics of solid solutions
7-04Dynamics and disorder in quasicrystals
7-05Chemi- and physisorbed species
7-06Dynamics of intercalation compounds
7-07Dynamics and disorder in molecular systems
7-08Magnetic excitations in inorganic complexes
7-09Magnetic thin films and surfaces