NIST meeting on polarized 3He spin filters, Jan. 28, 1999

[Tom Gentile]

Dear Folks:

[SOME OF YOU HAVE ALREADY RECEIVED THIS MESSAGE, BUT PLEASE NOTE THAT THE
DATE FOR THE MEETING IS JAN. 28. WE APOLOGIZE FOR MULTIPLE E-MAILS.
ONLY THOSE WHO RESPOND WILL RECEIVE FUTURE E-MAIL ON THIS MEETING.
IF YOU HAVE NOT ALREADY DONE SO, PLEASE RESPOND TO SNOW at IUCF.INDIANA.EDU
IF YOU ARE INTERESTED IN THE MEETING]

The NIST/Indiana/LANL polarized 3He collaboration invites you to an upcoming
meeting at NIST on Thursday, January 28, 1999.

The meeting will begin with a summary of the collaboration's progress in
polarized 3He-based neutron polarizers/analyzers, and then the floor will be
open for your ideas for neutron scattering experiments that can exploit this
technology.

Although further development is required, we have reached the stage where
practical application is feasible. We expect the first applications to be in
areas that are not currently well-served by conventional polarizer technology,
such as:

1)  polarizers/analyzers that must handle a large divergence, eg. SANS analysis
2)  broadband polarizers for spallation sources

Along these lines, our current neutron results include:

1)  NIST SANS polarization analysis test (separating coherent from incoherent
scattering)

2)  Demonstration of a broadband polarizer at LANSCE, as well as the unique
feature of highly accurate, transmission-based polarization measurement

Our technology for polarizing the gas is broad-based and includes

1)  spin-exchange optical pumping (most readily applicable) (tour at meeting)

2)  metastability-exchange optical pumping

(a)  Indiana - compression apparatus analogous to the current ILL/Mainz system

(b)  NIST - a new compact compression apparatus (tour at meeting).

Test experiments can often be done by simply transporting a cell full of
polarized
gas in a solenoid to the instrument, and such transport could even be done on
the NIST-Oak Ridge or Indiana-Argonne distance scale. The simplicity of the
spin-exchange apparatus also invites reproduction at other labs.

We plan to discuss expected near term improvements. To realize real
applications, we seek to identify directions for progress in 3He and
auxiliary technical issues (magnetic shielding, simple space considerations).

We envision an informal one-day meeting on Thursday, Jan. 28
at NIST.  We invite presentations of ideas for experiments, either as
scheduled short talks or in an open discussion session. Please respond if
you are interested in attending and/or if you have a conflict with the above
date. More information on the principles and status of polarized 3he neutron
polarizers can be provided on request.


Sincerely,

Tom Gentile, NIST
Alan Thompson, NIST
Gordon Jones, NIST
Mike Snow,Indiana, snow at iucf.indiana.edu, (812)-855-7914


for the collaboration

Thomas R. Gentile			phone:  301-975-5431
NIST					FAX:  301-926-1604
100 Bureau Drive, Stop 8461 		e-mail:  thomas.gentile at nist.gov
Gaithersburg, MD 20899-8461