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The system functions primarily through written reviews of proposals by expert referees. Normally, several reviews are sought for each proposal, using referees chosen by NIST staff. In addition, NCNR scientists carry out reviews for safety and technical feasibility.

After satisfactory reviews have been obtained, the Beam Time Allocation Committee (BTAC) of the NCNR rank-orders the proposals and assigns the amount of beam time to be allocated to each successful proposal for each experimental station. The BTAC meets twice a year to do this. The actual scheduling of experiments is carried out by NCNR staff. The BTAC has primary responsibility for proposal review, and provides advice to NIST and NCNR management on all aspects of the NCNR operation.

The current BTAC membership is:

The percentages of the total amount of beam time available to guest researchers through the proposal system are as follows.

30-m small angle neutron scattering (SANS) instrument* 67
ultra-small angle neutron scattering (USANS) instrument* 67
multi-angle crystal spectrometer (MACS)* 67
disk-chopper spectrometer (DCS)67
backscattering spectrometer (HFBS)*67
thermal neutron spin-polarized triple-axis spectrometer (BT7) 67
neutron spin-echo spectrometer (NSE)*67
polarized beam reflectometer (PBR)67
neutron imaging facility (NIF)25
MAGIK reflectometer/diffractometer 67
30-m NIST/Exxon/Texaco/U.Minnesota SANS instrument43
high-resolution powder diffractometer (BT1)25

*These instruments are partially supported by the National Science Foundation through its Center for High Resolution Neutron Scattering (CHRNS) at NIST.
The NG7 horizontal sample reflectometer and the SPINS cold-neutron triple-axis spectrometer are no longer being offered through regular user proposals. Interested parties may contact NIST staff to determine if access through collaborative research is feasible.

The relatively low percentages for some instruments may reflect the fact that they were constructed by and are operated by research consortia.

Continuation proposals as such are no longer being accepted as a separate class of proposals. All proposals are subject to peer review by expert external referees, as well as by the BTAC.

Last modified 11-September-2015 by website owner: NCNR (attn: )