ORNL Neutron Sciences Update

1. MUON & NEUTRON &
SYNCHROTRON RADIATION NEWS
(Fig. 1). The development of online approaching 1 L. To reduce polariza- References
optical pumping of 3He gas to main- 1. A. Abragam, Principles of Nuclear Magnetism,
tion relaxation arising from field gra-
Oxford University Press, Oxford, England
tain time-independent neutronic dients inside magnetically shielded
(1961).
performance is underway for a few solenoids, we have optimized the
2. W.C. Chen et al., Rev. Sci. Instrum. 75, 3256
instruments. field homogeneity by modeling and (2004).
The key technical challenges in ap- mapping the field, and most useful- 3. T.R. Gentile et al., J. Appl. Cryst. 33, 771
plying 3He spin filters to neutron ly, by measuring the polarization re- (2000).
scattering are 1) producing a large laxation of the sealed low-pressure 4. W.C. Chen et al., Physica B in press.
volume of highly polarized 3He gas MEOP cells.
W.C. Chen, J.A. Borchers,
and 2) minimizing the 3He polariza- We have built a few compact mag-
R. Erwin, T.R. Gentile,
tion decay. netically shielded solenoids that
J.W. Lynn
We have constructed two SEOP sys- yield field-gradient induced relax-
ation times up to 3000 h for a 3He National Institute
tems capable of producing 75 % po-
of Standards and Technology,
larized 3He gas at pressures of (1 to pressure of 105 Pa over a cell volume
Gaithersburg, Maryland, USA
2) x 105 Pa in cells having volumes of 1 L.
News from SNS
ORNL Neutron Sciences Update
Both Oak Ridge National Laboratory struments through a combined user 2007. It is anticipated that the initial
neutron scattering facilities complet- program. The Integrated Proposal cycles will be devoted to testing of
ed safety reviews in April 2007. Tracking System is undergoing beta instruments and operational para-
These successes enable the High Flux testing. It will track proposals meters, with general users arriving
Isotope Reactor (HFIR) and the Spal- throughout the experimental later this summer. Four HFIR instru-
lation Neutron Source (SNS) to con- process, including proposal submis- ments will be initially available fol-
tinue preparations for users to per- sion, safety and science reviews, and lowing restart of the reactor: three
form neutron scattering experiments. beam time scheduling. The High triple-axis spectrometers and the
A recently developed web-based Flux Isotope Reactor passed a formal residual stress diffractometer. Future
proposal submission process enables review assessing readiness for restart capabilities at world-class levels will
both facilities to coordinate beam of operations. Neutron production is be enabled by a new cold source for
time on the neutron scattering in- expected to begin again in early May two small-angle neutron scattering
Figure 1. A 24-ton portion of the 65m3 ARCS Figure 2. The POWGEN3 powder diffractometer team has completed installation of neutron guide.
scattering tank is lifted into position. Photo credit: Luke Heroux/ORNL.
Photo credit: Mark Loguillo/ORNL.
Vol. 12 n. 2 July 2007 • NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE
33

2. MUON & NEUTRON &
SYNCHROTRON RADIATION NEWS
beam lines; these will be directed to proved limit up to the design capa- sign energy of 1.0 GeV. The first
the biomaterials, pharmaceutical, bility of 2 MW. Power of the acceler- three SNS instruments continue their
and polymer communities. In com- ator will be increased beyond 100kW commissioning with the goal of wel-
ments referring to the re-start of as the predictability and reliability of coming general users in October
HFIR operations, ORNL group neutron production also increases. In 2007: BASIS – Backscattering Spec-
leader Greg Smith said “Neutron the most recent SNS operations cy- trometer, and the Magnetism and
scatterers are anxious to start doing cle, proton beam power routinely de- Liquids Reflectometers.
experiments using the facilities now livered to the target achieved the This involves testing major compo-
available at HFIR. In particular, the goal of approximately 60 kW at an nents such as the data acquisition
cold neutrons will give us new capa- operating frequency of 15 Hz. The system, neutron choppers, incident
bilities almost immediately to study accelerator also operated for four beam monitor, and neutron detec-
complex molecules and biological hours at 90 kW. In another test of the tors. Test measurements of various
samples using the new SANS instru- accelerator system, the operating fre- samples have been performed. Test-
ments in the guide hall. These instru- quency was increased to 30 Hz for ing of this equipment including se-
ments, combined with our state-of- several hours of neutron production lected sample environments and po-
the-art spectrometers already in the at 30 kW; this is in preparation for larizers will continue during the next
beam room, will certainly usher in a increasing the power during the next operations cycle. Advances continue
new era of scientific productivity for operations cycle. A new world ener- in the construction of other instru-
ORNL researchers and users from gy record for proton beam accelera- ments at SNS with an extremely
around the world”. The most recent tion in a linear accelerator was set on busy period of commissioning and
SNS operation cycle was completed February 19, 2007. SNS accelerated user activity beginning in fall 2007
April 15, 2007. A review was held the proton beam to 1.01 GeV, break- (see accompanying table).
April 2007 to assess readiness for ac- ing the previous record of 0.95 GeV, The POWGEN3 powder diffrac-
celerator operations at proton beam which SNS achieved in December tometer finished guide installation
power above our present 100 kW ap- 2005, and reaches the intended de- and is installing shielding over the
Schedule of ORNL Instruments through 2008
High Flux Isotope Reactor Spallation Neutron Source
Scheduled for General User Program in 2007
HB-1, Polarized Triple-Axis Spectrometer BL 2 , BASIS - Backscattering Spectrometer
HB-1A, Ames Lab Triple-Axis Spectrometer BL-4a, Magnetism Reflectometer
HB-3, Triple-Axis Spectrometer BL-4b, Liquids Reflectometer
HB-2B, Residual Stress Diffractometer
Commissioning Scheduled for 2007, General Users in 2008
CG-2, 40m SANS BL-18, ARCS - Wide Angular Range Chopper Spectrometer
CG-3, 35m BIOSANS
Commissioning Scheduled for 2008, General Users in 2009
BL-3, High Pressure Diffractometer
BL-5, CNCS – Cold Neutron Chopper Spectrometer
BL-6, EQ-SANS – Extended Q-Range Small Angle Neutron Diffractometer
BL-7, VULCAN – Engineering Diffractometer
BL-11a, POWGEN3, Powder Diffractometer
BL-13, Fundamental Physics Beam Line
BL-17, SEQUOIA – Fine Resolution Fermi Chopper Spectrometer
NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE • Vol. 12 n. 2 July 2007
34

3. MUON & NEUTRON &
SYNCHROTRON RADIATION NEWS
guide sections. Large sample vessels ORNL User Meeting October 8-12, Oak Ridge facilities. Second, we
for ARCS - Wide Angular Range 2007 wish to receive feedback on needed
Four ORNL user facilities – SNS,
Chopper Spectrometer [volume of 65 advances in areas such as develop-
m3] and SEQUOIA – Fine Resolution HFIR, the Center for Nanophase Ma- ing pump-probe techniques to study
terials Sciences, and the Shared Re-
Fermi Chopper Spectrometer [vol- non-equilibrium phenomena at mi-
ume of 250 m3] have been received search Equipment user facilities – crosecond timescales, combining
are coordinating a program for a
and installed. sample environment stages (perhaps
combined User Week, October 8-12,
Construction of the external instru- high magnetic fields, high pressure,
2007, to be held at ORNL. The first
ment buildings for the CNCS – Cold and low temperature simultaneous-
goal of this meeting is to increase in-
Neutron Chopper Spectrometer and ly), and combining characterization
techniques (x-ray and neutron) on
the same instrument. Third, there is
Figure 3. This UV image is used
an opportunity to acquaint new
to assess optical alignment of
users with capabilities of some of the
neutron guide sections of the
VULCAN engineering diffrac- major techniques used at SNS and
tometer. Note the continuous
HFIR through small workshops.
smooth lines from the corners
More information on this combined
with no breaks or jumps where
user meeting, including registration,
glass sections meet.
Image credit: Marc Shoemak- agenda, and lodging, can found at
er/ORNL.
http://neutrons.ornl.gov or by email
to neutronusers@ornl.gov.
A.E. Ekkebus
terest and awareness of the impor-
VULCAN – Engineering Diffrac-
Neutron Scattering Science Division
tant scientific research challenges
tometer is scheduled for completion
Oak Ridge National Laboratory
that are being addressed at these
in summer 2007.
Judges come to Lawrence Berkeley National Lab to learn
about Science
In late March, 55 state and federal involving novel scientific evidence. Technology Adjudication Resource
judges came to Lawrence Berkeley They toured the Advanced Light Center (ASTAR), a non-profit corpo-
National Laboratory for a week-long Source, focusing on its protein and ration that seeks to improve the ca-
conference designed to give the cellular imaging capabilities. pacities of the nation’s courts in re-
judges an orientation to the emerg- They also toured a nanotechnology solving highly technical cases.
ing fields of nanotechnology, syn- research center, met with Berkeley Judges who attended the conference
thetic biology, and environmental Lab Director Chu and several other were certified by ASTAR and will
biotechnology, and enhance their Lab scientists, isolated DNA frag- provide case-related leadership later
ability to preside over complex cases ments and examined spectroscopy this year at the group’s national con-
images, and dissected imaginary ferences.
cases involving nanoparticles, ra- ASTAR’s mission over the next two
dionuclide releases, and bioremedia- years is to provide an orientation on
tion. “They came to Berkeley Lab be- the fundamentals of emerging scien-
cause we are known as the center for tific disciplines to every court juris-
science, and they need to know how diction in the U.S.
science works”, says Terry Hazen, a
microbial ecologist in the Earth Sci- D. Krotz
ences Division who has helped Communications Department
judges bone up on the fundamentals Lawrence Berkeley National Lab
of science for the past eight years. phone: (510) 486-4019
Hazen organized the March 25 to fax: (510) 486-6641
March 30 conference under the aus- DAKrotz@lbl.gov
Judges get an orientation to emerging scientific
pices of the Advanced Science &
fields from Lab microbial ecologist Terry Hazen.
Vol. 12 n. 2 July 2007 • NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE
35