CEC Abstracts in PDF format (as of 7/3/07) - CEC-ICMC 2013

CEC 2007 - Abstracts
C1-Q-06 Piezo-Hydraulic Actuation for Driving High
Frequency Miniature Split-Stirling Pulse Tube
Cryocoolers
I. Garaway, G. Grossman, Technion - Israel Institute
of Technology.
In recent years piezoelectric actuation has been identified as a
promising means of driving miniature Stirling devices. It supports
miniaturization, has a high power to volume ratio, can operate at
almost any frequency, good electrical to mechanical efficiencies, and
potentially has a very long operating life. The major drawback of
piezoelectric actuation, however, is the very small displacements that
this physical phenomenon produces. This study shows that by
employing valve-less hydraulic amplification, an oscillating pressure
wave can be created that is sufficiently large to drive a high frequency
miniature pulse tube cryocooler (as high as 350 Hz in our
experiments, and perhaps higher). Beyond the direct benefits
derived from using piezoelectric actuation there are further benefits
derived from using the piezo-hydraulic arrangement with membranes.
Due to the incompressibility of the hydraulic fluid the actuator may be
separated from the main body of the cryocooler by relatively large
distances with almost no detrimental effects, and the complete lack of
rubbing parts in the power conversion processes makes this type of
cryocooler extremely robust. The design and experimental device
along with some test results will be presented.
C1-Q-07 Demonstration of a superconducting detector
cooled by electron-tunneling refrigerators
J.N. Ullom, J.A. Beall, W.D. Duncan, F. Finkbeiner,
G.C. Hilton, K.D. Irwin, D.R. Schmidt, L.R. Vale,
NIST; N.A. Miller, G.C. O`Neil, NIST/University of
Colorado Boulder; D.J. Benford, J.A. Chervenak,
S.H. Moseley, R.F. Silverberg, NASA GSFC; T.C.
Chen, Global Science and Technology.
We have successfully cooled a Transition-Edge Sensor (TES) using
thin-film, solid-state refrigerators based on Normal metal/
Insulator/Superconductor (NIS) tunnel junctions. The cooling
mechanism is the preferential tunneling of the highest energy (hottest)
electrons through the biased NIS junctions. We describe the cooling
performance, temperature noise, and energy resolution of the NIScooled
TES. In particular, we show that the NIS refrigerators
introduce no detectable noise in the TES operation. We also describe
ongoing efforts to improve the cooling performance of NIS
refrigerators and the ease with which they can be coupled to usersupplied
payloads. NIS refrigerators can cool from temperatures near
0.3 K to below 0.1 K. The calculated power dissipation to cool 1,000
thin-film sensors is 1-10 microWatts. Combining a pumped He-3
system with NIS refrigerators provides a compact, lightweight
alternative to adiabatic demagnetization refrigerators and dilution
refrigerators.
Wednesday, 07/18/07 Plenary
8:00am - 9:00am
C2-A Wednesday Plenary Session
Wednesday, 07/18/07 Oral
9:00am - 10:30am
C2-B He II Heat Transfer and Fluid
Mechanics - II
C2-B-01 An experimental study of He II two-phase flow
in a long horizontal pipe
M. Takahashi, T. Kuriyama, T. Yazawa, I. Watanabe,
K. Nakayama, Toshiba Corp.; Y. Ota, T. Okamura,
Tokyo Tech.
Superconductor cavities used in linear collider are cooled below 2K in
superfluid helium to enhance the generated electric field. In some
linear collider such as planned in the International Linear Collider
project (ILC), the cryogenic system will have a considerably long
horizontal pipe, more than hundred meters, in which two-phase
superfluid helium flows. One of the key issue for the cryogenic design
is the gradient of the liquid level in the pipe. It should be designed as
small as possible to cause the dry-out at somewhere of the pipe. We
have developed a test apparatus of He II two-phase flow in a long
pipe. The apparatus is comprised mainly of a He II vessel, a twophase
flow pipe with 4 m in length and 32 mm in diameter, and some
cavity vessels. Instead of cavities, electric heaters gave the thermal
load. The gradient of the liquid level as a function of the load was
measured by using two level meters. The experimental results were
compared to numerical results.
C2-B-02 Experimental facility for comparison of high
Reynolds number turbulence in both HeI and HeII : first
results
B. Rousset, M. Bon Mardion, D. Communal, F.
Daviaud, P. Diribarne, B. Durbrulle, A. Forgeas, A.
Girard, P. Roussel, CEA; C. Baudet, Y. Gagne, P;
Thibault, UJF; B. Castaing, ENS; B. Hebral, P.
Roche, CNRS.
Turbulence SuperFluid (TSF) project will use cryogenic liquid helium
for the fundamental study of turbulent phenomena. For this purpose
we have carried out an experiment of passive grid turbulence which is
able to work in HeI as well as in HeII. The flow of liquid helium will
be generated by a cold Barber and Nichols circulating pump, whereas
helium flow temperature is kept constant by means of a heat
exchanger immersed in a saturated bath, which mainly evacuates the
heat due to friction.
This experiment will use the CEA Grenoble refrigerator (nominal
capacity of 400 Watt at 1.8 K) to remove the heat due to pressures
losses in this high Reynolds number experiment. In order to solve the
Kolmogorov scale associated with such high flow local
instrumentation (e.g. sub-micrometer anemometer) was developed.
Use of this local and fragile instrumentation in a quasi industrial
environment arises some difficulties we discussed here while the
solutions adopted are also described.
Finally, first results obtained both in superfluid and in normal helium
are presented. For this last case, a permanent mass flow rate of few
hundreds of g/s was achieved.
C2-A-01 The COBE Mission: How Cryogenics is
Revolutionizing Astronomy and Astrophysics
J. Mather, NASA/Goddard Space Flight Center.
The development of deep cooling for space science applications has
enabled an extraordinary series of discoveries in astrophysics, ranging
from infrared astronomy to X-ray astronomy and tests of general
relativity to observations of the Big Bang itself. I will describe the
instrument package and the cooling concepts used on the Cosmic
Background Explorer satellite, and the scientific results that led to the
Nobel Prize in Physics for 2006. The James Webb Space Telescope,
now in preparation for launch in 2013, will use both radiative and
active cooling to extend the science of the Hubble Space Telescope
and the Spitzer Space Telescope. I will discuss the cooling concepts
for these missions and others, and speculate on the future of
cryogenics in space science.
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