# GENERAL

#### JPL Scientist Garners Award

John Dick, the JPL Project Scientist for the Superconducting Microwave
Oscillator (SUMO) flight experiment, received this year's European Time
and Frequency Award. The award, granted every two years by the French
Society of Microtechnology and Chronometry, recognizes exceptional
contributions either for fundamental advances or for present or future
applications. Dick was granted the award for "contributions in the
fields of atomic frequency standards physics, of cryogenic oscillator
technologies, and of low noise electronics and measurements systems.\"
He received a cash award and a limited-edition original print and
certificate.

## EDUCATION and OUTREACH

FUTURE FLIGHT PROGRAM - ISSA PHASE I/II/III

**[DYNAMX Team Describes New Type of High Resolution
Thermometers]{.underline}**

A detailed paper entitled \"PdMn and PdFe: New Materials for Temperature
Measurement Near Two Kelvins\" by B. J. Klemme\*, M.J. Adriaans+, P. K.
Day+, D. A. Sergatskov\*, T. L. Aselage#, and R. V. Duncan\*
(\*University of New Mexico; +Jet Propulsion Laboratory; #Sandia
National Laboratories) will appear in the July, 1999 issue of the
Journal of Low Temperature Physics. This new class of high-resolution
thermometry has been developed for fundamental physics experiments, both
ground-based, and in orbit. These thermometers may be subjected to great
extremes in temperature, humidity, and pressure without damaging the
thermometric elements, which is a definite advantage over conventional
materials for high-resolution thermometry. These materials have been
used in ground-based experiments on the Critical Dynamics in
Microgravity Experiment (DYNAMX), and they are being prepared for use
with the space version of this experiment.

**[Summer Student Will Develop Lower Temperature Thermometers for
EXACT]{.underline}**

Ms. Terri Yu has joined the EXACT (Experiments Along Coexistence near
Tricriticality) team on a Summer Undergraduate Research Fellowship
(SURF). Ms. Yu just completed her freshman year at the Massachusetts
Institute of Technology. She will be helping the EXACT team this summer
to develop high resolution thermometers with nanokelvin temperature
resolution over the temperature range from 0.5K to 1K. This work will
extend the temperature range that can be studied using such high
accuracy thermometry. Previously developed nanokelvin resolution
thermometers work only at higher temperatures, from about 1.7K to 3.3K.

ISSUES AND CONCERNS

SCIENCE HIGHLIGHTS

FUNDAMENTAL PHYSICS

**[Thesis Work Studies Nucleation of Non-equilibrium
Phases]{.underline}**

Charles Elbaum of Brown University reports that Timothy A. Johnson has
completed his doctoral thesis and fulfilled all the requirements for the
Ph.D. degree. His thesis title is \"Out of Equilibrium Nucleation in the
Solidification of Helium.\" In his investigations he found that the
solid emerging from the liquid, when the pressure is raised above the
melting curve, is often not the one expected from the known, equilibrium
bulk phase diagram. The conditions and processes by which this
out-of-equilibrium phenomenon occurs have been studied as a function of
temperature and pressure. The results reveal that the long-held,
classical models of nucleation do not apply to the case under study.
Other models are being explored.

This study relates to NASA\'s program of microgravity research in at
least two ways:

1\) It provides new information on first order phase transitions and
provides the impetus to explore the effects of gravity on the phenomena
observed.

2\) It offers guidance to the possible use of nucleation of metastable
phases, with special properties, in other areas (e.g. materials science,
life sciences\...)

**[Laser Cooling Experiment Measures Zero Point Motion]{.underline}**

Wolfgang Ketterle of MIT reports that the following description of their
article in Physical Review Letters appeared in PHYSICS NEWS UPDATE, The
American Institute of Physics Bulletin of Physics News (Number 433 June
15, 1999) by Phillip F. Schewe and Ben Stein.

ZERO-POINT MOTION IN A BOSE-EINSTEIN CONDENSATE has been quantitatively
measured for the first time, allowing researchers, in effect, to study
matter at a temperature of absolute zero. According to quantum
mechanics, objects cooled to absolute zero do not freeze to a complete
standstill; instead they jiggle around by some minimum amount. MIT
researchers (Wolfgang Ketterle, 617-253-6815) measured such \"zero-point
motion\" in a sodium BEC, a collection of gas atoms that are
collectively in the lowest possible energy state (Update 233). According
to Ketterle, \"the condensate has no entropy and behaves like matter at
absolute zero.\" The MIT physicists measured the motion (or lack
thereof) by taking advantage of the fact that atoms absorb light at
slightly lower (higher) frequencies if they are moving away from
(towards) the light. To determine these Doppler shifts (100 billion
times smaller than those of moving galaxies), the researchers used a
technique known as Bragg scattering. In this technique, atoms absorb
photons at one energy from a laser beam and are stimulated by a second
laser to emit a photon at another energy which can be shifted upward or
downward depending on the atoms\' motion towards or away from the
lasers. Measuring the range in energies of the emitted photons allowed
the researchers to determine the range of momentum values in the
condensate. Multiplying this measured momentum spread (delta p) by the
size of the condensate (delta x) gave an answer of approximately h-bar
(Planck\'s constant divided by 2 pi)\--the minimum value allowed by
Heisenberg\'s uncertainty relation and quantum physics. While earlier
BECs surely harvested this zero-point motion, previous measurements of
BEC momentum spreads were done with exploding condensates having
energies hundreds of times larger than the zero-point energy. (J.
Stenger et al., Physical Review Letters, 7 June 1999.)