CP620, Shock Compression of Condensed Matter - 2001
edited by M. D. Furnish, N. N. Thadhani, and Y. Horie
© 2002 American Institute of Physics 0-7354-0068-7/02/$ 19.00
TEMPERATURE CONTROLLED VESSEL FOR EQUATION OF
STATE MEASUREMENTS
Ted D. Rupp1, Russell J. Gehr1, David B. Stahl2, Stephen A. Sheffield2, and
David L. Robbins2
*Honeywell Federal Manufacturing & Technologies/New Mexico, Los Alamos, NM 87544*
Dynamic Experimentation Division, Los Alamos National Laboratory, Los Alamos, NM 87545
Abstract. We have designed and constructed a vessel capable of heating and cooling hazardous
samples used in the laser-driven miniflyer experiments. For cooling, either liquid or gaseous nitrogen
may be used. For heating, an electric element is used. The accessible temperature range is -100 °C to
300 °C. O-ring containment seals in the inner containment vessel establish temperature limits. The
outer level of containment uses copper gaskets and commercial vacuum components. The vessel may
be operated with a gas atmosphere or a vacuum. Temperature is monitored using two thermocouples,
one on the heater and one on the inner containment vessel. A controller module monitors one
thermocouple to reach and maintain the desired temperature. Using this vessel we can perform
equation of state or spall strength measurements on hazardous materials in different phases or near
solid-solid or solid-liquid phase transitions. Initial data taken with this system will be presented.
a shock wave propagating through the heated
material can induce a phase change. Investigation
of these material properties requires a temperature
control vessel that can safely contain the hazardous
material.
INTRODUCTION
The dynamic behavior of materials can be
strongly dependent on the material temperature. [14] In experiments involving shock waves, such as
spall strength and equation of state measurements,
this is especially true near phase transformations.
[1,2] The pressure change due to the shock can
induce a phase change, altering the material
properties as the shock wave passes. For example,
the spall strength drops precipitously at
temperatures above 90% of a metal's melt
temperature. [1,2] To witness this and other effects
it is necessary to control the material temperature.
Hazardous materials such as actinides typically
have one or more solid-solid phase transitions. [5]
At atmospheric pressure most of these transitions
occur at very high temperatures. However, for
several actinides a transition is accessible at high
pressure and moderate temperatures. In these cases
* This work was supported by the NNSA Enhanced Surveillance
Campaign through contract DE-ACO4-01AL66850.
FIGURE 1. Picture of the temperature control vessel.
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Secondary containment is accomplished with
commercial vacuum components. A 6-way cube
for 4 l/2 inch conflat flanges is used as the main
body of the vessel. The temperature control unit,
manufactured by Thermionics Northwest Inc.,
attaches to the top opening of the cube. Two
sapphire viewports, one each for the pump and
probe beams, cover opposite side openings. These
viewports are specified for both vacuum and
overpressure up to 100 psig. Thus, the sample may
be heated with an atmosphere present in the vessel
without concerns of breaking the viewport seal.
This situation is necessary for hazardous samples;
contamination could occur if primary containment
failed and a vacuum pump pulled the atmosphere
out of the vessel. Therefore experiments on
hazardous samples are done in an atmosphere. The
remaining cube openings are used for vacuum
connections, sample insertion, or are blanked off.
The temperature controller heats the sample using
an electric heater and cools the sample using liquid
or gaseous nitrogen flowing through the unit. Heat
transfer between the temperature controller and the
inner vessel is achieved at one face only. Therefore
there are two thermocouples available to monitor
the temperature, one at the heater interface and one
on the side of the inner vessel. The temperature
controller unit monitors one thermocouple and a
user-selectable program drives the electric heater so
that the approach to the preset temperature level
does not significantly overshoot or undershoot.
Since the built-in thermocouples do not come
into direct contact with the target material, it was
necessary to investigate the relation between the
thermocouple readings and the actual target foil
temperature. For these tests, an extra thermocouple
was mounted against the target foil. The windows
on the probe side of the target had holes drilled
through them so the thermocouple could be epoxied
in place. A vacuum flange with thermocouple wire
throughputs was used to connect the thermocouple
to an external meter. The temperature of the target
was compared with the temperatures recorded by
the two thermocouples during heating and cooling
cycles to determine the time required to reach
equilibrium. Tests were performed in vacuum and
at atmospheric pressure.
Two target materials were used for the tests:
copper and bismuth, each in a foil approximately
100 micrometers thick. Copper was chosen for its
We have developed a temperature controlled
vessel for use with the laser-driven miniflyer setup.
[6] (See Fig. 1.) In the miniflyer system a 3 mm
diameter, 0.05 to 0.10 mm thick flyer is launched at
high velocity by a single shot laser. The flyer
impacts a target foil, inducing a shock wave. The
front surface velocity of the target is monitored
using dual velocity interferometers to determine
spall strength or equation of state. Given the small
size of the flyer, the target material is typically 0.10
to 0.20 mm thick and 15 mm in diameter.
EXPERIMENTAL
(a)
T
K
li__JNV
i;
"
S \0-ring
o
L^^>
^ grooves
Jr
55
Windows
Target Foil
Flyer Assembly
Windows
FIGURE 2. a) Inner containment vessel, b) Target stacking
arrangement.
To safely confine hazardous materials during a
dynamic experiment, the temperature controlled
vessel requires two levels of containment. Primary
containment is accomplished with an inner vessel.
(See Fig. 2a.) This chamber is made of copper for
efficient heat conduction. It consists of two pieces
that screw together. To provide adequate seals,
there are three o-rings: two o-rings seal the front
and rear windows to the chamber and one o-ring
seals the two pieces of the chamber together. Glass
or thick PMMA windows are used to contain debris
generated during the experiment. The pump laser is
sufficiently energetic to pulverize the flyer substrate
window, creating glass dust. In addition, it is
possible to achieve flyer velocities that break
through the target material. Thus the probe side
windows may be required to stop the flyer while
maintaining the seal. For these reasons two
windows are used on both sides of the vessel. (See
Fig. 2b.)
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high thermal conductivity, 401 W/m°K, and as one
of the materials commonly used in our setup.
Bismuth was chosen for its extremely low thermal
conductivity: 7.9 W/m°K. In addition to being a
worst-case scenario, this conductivity is similar to
those of uranium and other actinides.
an atmosphere the heater element reaches
temperature more slowly, and the inner vessel and
target foil temperatures closely follow the heater
temperature. The probable cause of this difference
is the addition of conductive heating due to the
atmosphere.
In an atmosphere both the copper and the bismuth
targets achieved thermal equilibrium at the 250 °C
setting in approximately 35 minutes. For the
copper foil the actual temperature attained was
258 °C, which is slightly higher than the desired
temperature. For the bismuth target the actual
temperature attained was 240 °C. This is lower
than the copper target due to the low thermal
conductivity of bismuth (7.9 W/m°K). In both
cases the rate of heating is sufficient to perform
several experiments in one day.
RESULTS AND DISCUSSION
(a)
•
«
*
D
o
O
0
10
20
30
Heater in air
Inner vessel in air
Target foil in air
Heater in vacuum
Inner vessel in vacuum
Target foil in vacuum .
40
50
60
•
•
•
n
o
O
time [min]
250
(b)
Cooler in dry N2
Inner vessel in dry N2
Target foil in dry N2
Cooler in vacuum
Inner vessel in vacuum
Target foil in vacuum
200
150
Heater in air
Inner vessel in air
Target foil in air
Heater in vacuum
Inner vessel in vacuum
Target foil in vacuum .
100
I 50
0
0
10
20
30
40
50
(a)
0
10
20
30
40
50
60
70
time [min]
60
20
time [min]
FIGURE 3. Measured temperature of the heater, the side-wall
of the inner vessel, and the target foil for (a) copper and (b)
bismuth foils, with a temperature goal of 250 °C.
*
*
*
n
o
(b)
0
-20
-40
-60
Cooler in air
Inner vessel in air
Target foil in air
Cooler in vacuum
Liner vessel in vacuum
Target foil in vacuum •
!
The results of the heating tests for copper and
bismuth targets are shown in Fig. 3. From room
temperature the targets were heated to 250 °C. This
temperature was chosen based on the melting
temperature of bismuth, 271 °C. The maximum
current used to drive the electric heater was set
between 6.0 and 6.5 amps. This causes the
-80
-100
-120
IDDD
0
10
20
30
40
50
60
a
D
70
time [min]
FIGURE 4. Measured temperature of the heater, the side-wall of
the inner vessel, and the target foil for (a) copper and (b) bismuth
foils, with a temperature goal of -100 °C.
temperature to rise quickly, but not rapidly enough
to damage the system.
From Fig. 3 it is evident that there are significant
differences between heating in a vacuum and
heating in an atmosphere. In a vacuum, the heater
element rapidly attains the desired temperature, but
the inner vessel and the target foil temperatures rise
much more slowly and do not reach their goal. In
The results for cooling the copper and bismuth
foils, shown in Fig. 4, are similar to the heating
tests: the cooling element achieves temperature
more rapidly in vacuum, but the inner vessel and
target foil do not achieve the desired temperature.
In a dry nitrogen atmosphere the cooling element
cools more slowly, but the inner vessel and target
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foil cool more rapidly and reach equilibrium in
under 40 minutes. Note in this case that the inner
vessel and target foil maintain similar temperatures,
but do not follow the cooling element temperature.
In addition, they do not reach the same temperature
as the cooler, but stabilize approximately 10
degrees warmer. With the cooling element at
-110 °C, the target foil reaches -100 °C.
Once again the bismuth foil takes longer to
achieve equilibrium than does the copper foil. The
time difference is relatively small, and in each case
the foil achieves equilibrium in well under one
hour.
It is important to note that the difference in
reported temperature between the thermocouple on
the side of the inner vessel and the thermocouple on
the target foil is less than 2%. Therefore it is
possible to know the target foil temperature by
monitoring the inner vessel thermocouple.
1
CONCLUSIONS
We have demonstrated a new temperature control
vessel for dynamic experimentation on hazardous
samples. The two levels of containment designed
into the vessel ensure that hazardous material
cannot escape to create contamination.
The
temperature control system is capable of setting the
sample temperature between -100 °C and 300 °C.
Starting at room temperature, the controller can
achieve the desired temperature in less than 1 hour.
Including time to return the sample to near room
temperature after the test, this implies that up to
four experiments can be performed in a single day.
We have performed temperature-dependent
equation of state measurements on bismuth foils.
The preliminary data shows the boundaries of the
solid I, II, and III phases, and the solid-liquid
transition, in agreement with the known phase
diagram of bismuth.
139 °C
200
8
In the two highest temperature experiments, at
207 °C and 230 °C, the measured shock did not
attain high pressures. At these temperatures, the
solid-liquid phase transition is accessible. [7] Our
preliminary conclusion is that the shock wave
propagates much slower in the liquid and therefore
is overtaken by the relief wave.
100
50
0
0.0
0.2
0.4
0.6
REFERENCES
0.8
time [|is]
1. Kanel G.I., Razorenov S.V., Bogatch A., Utkin A.V.,
Fortov V.E., and Grady D.E., J. Appl. Phys. 79, 83108317(1996).
FIGURE 5. Equation of state measurements as a function of
temperature on bismuth foils.
2. Razorenov S.V., Bogatch A.A., Kanel G.I., Utkin
A.V., Fortov V.E., and Grady D.E, in Shock
Compression of Condensed Matter - 7997, AIP, New
York, 1997, pp. 447-450.
3. Gu Z. and Jin X., in Shock Compression of
Condensed Matter - 1997, AIP, New York, 1997, pp.
467-470.
4. Gu Z., Jin X., and Gao G, J. Mail Sci. 35, 2347-2351
(2000).
5. Young D.A., Phase Diagrams of the Elements,
Equation of state measurements were performed
on bismuth foils at temperatures between -90 °C
and 230 °C. At these temperatures and at pressures
below 4 GPa, bismuth has four different solid
phases, as well as the liquid phase. Analysis of the
initial data shows at least one solid-solid phase
transition in all of the low temperature shots. The
pressure at which this transition occurs decreases
slowly with increasing temperature, in agreement
with the bismuth phase diagram. [5] This is the
solid I to solid III phase transition, which is weakly
dependent on temperature. In addition, a second,
lower-pressure phase transition is evident in the
shots at 22 °C and 139 °C. This is the solid I to
solid II phase transition, which is strongly
temperature dependent.
University of California Press, Los Angeles, 1991.
6. Stahl D.B., Gehr R.J., Harper R.W., Rupp T.D.,
Sheffield S.A., and Robbins D.L., in Shock
Compression of Condensed Matter - 7999, AIP, New
York, 1999, pp. 1087-1090.
7. Asay J.R., J. Appl Phys. 45,4441-4452 (1974).
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