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Apparatus for XRay Measurements at Very High PressureE. A. Perez—Albuerne, K. F. Forsgren, and H. G. Drickamer Citation: Review of Scientific Instruments 35, 29 (1964); doi: 10.1063/1.1718703 View online: http://dx.doi.org/10.1063/1.1718703 View Table of Contents: http://scitation.aip.org/content/aip/journal/rsi/35/1?ver=pdfcov Published by the AIP Publishing Articles you may be interested in Instrument for x-ray magnetic circular dichroism measurements at high pressures Rev. Sci. Instrum. 78, 083904 (2007); 10.1063/1.2773800 High precision powder xray diffraction measurements at high pressures Rev. Sci. Instrum. 61, 2571 (1990); 10.1063/1.1141918 Measurements of xray diffraction for liquid metals under high pressure Rev. Sci. Instrum. 60, 2425 (1989); 10.1063/1.1140736 High Pressure—High Temperature, XRay Diffraction Apparatus Rev. Sci. Instrum. 35, 175 (1964); 10.1063/1.1718773 Apparatus for XRay Patterns of the High Pressure Modifications of Ice Rev. Sci. Instrum. 7, 82 (1936); 10.1063/1.1752086
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THE REVIEW OF SCIENTIFIC INSTRUMENTS VOLUME 35. NUMBER 1 JANUARY 1964
Apparatus for X-Ray Measurements at Very High Pressure*
E. A. PEREZ-ALBUERNE, K. F. FORSGREN, AND H. G. DRICKAMER
Department of Chemistry and Chemical Engineering and Materials Research Laboratory, University of Illinois, Urbana, Illinois
(Received 5 August 1963; and in final form, 16 September 1963)
An apparatus has been developed which permits x-ray powder patterns to be obtained to over 500 kilobars pressure. The apparatus is derived in part from the supported tapered piston electrical resistance apparatus in use in this laboratory, but the x rays are transmitted through a thin layer of LiH with suitable platinum collimation. The pressures are established by measuring the change of lattice parameter of a suitable marker mixed with the sample. These changes are then compared with volume changes obtained in shock wave work. Usual markers used to date include silver, rhodium, and palladium. Typical data for sample pressure versus average applied pressure for these metals are given. Also included is the change in lattice parameter with pressure for CsCI to 500 kilobars. The results are compared with the extrapolation of Bridgman's data.
A HIGH pressure x-ray cell has been developed which pennits measurements on simple substances to pres
sures as high as 500 kilobars. The experimental method is in part derived from previous high pressure optical and electrical methods used in this laboratory! and in part from other high pressure x-ray work.2 •3 The high pressure x·ray literature to 1961 is reviewed by Jamieson and Lawson.2 A more recent technique for high pressures is discussed by the same authors.3 Hall et al.4 have recently published still another development.
The present apparatus consists of a cell, a press, an x-ray source, and a detection system. The essentially different feature is the cell. Figure 1 shows an exploded view. The cell body consists of four pieces: (1) an outer jacket with a i-in. entrance hole and a i-in. slot milled to cover 1800
angle for the scattered radiation, (2) an inner jacket with a a\-in. entrance hole and a 332-in. slot, (3) a ring slotted for entering and scattered beams which threads into (2), and (4) a flat ring which threads into (2) and abuts against (3). The types of materials used for all parts and all important dimensions are summarized in Table I. As an be seen from the table, cells with two dimensions of piston are used. The t-in. piston cell gives better lines with a lower pressure range than the i-in. cell.
The pistons are grade 999 Carboloy, work hardened as in the electrical apparatus. They have an 180 taper and a 0.04S-in. flat. Pertinent dimensions are shown in Table 1. Pyrophyllite disks are machined to fit the taper precisely and are sanded to leave exactly a 0.04S-in. hole in the center. The sample containing disk is the most important feature and is shown in detail in Fig. 2. It consists'of a
* This work was supported in part by the U. S. Atomic Energy Commission and in part by the Petroleum Research Fund of the American Chemical Society.
1 H. G. Drickamer and A. S. Balchan in Modern Very High Pressure Techniques, edited by R. H. Wentorf, Jr. (Butterworths Scientific Publications Ltd., London, 1962).
I J. C. Jamieson and A. W. Lawson in Modern Very High Pressure Techniques, edited by R. H. Wentorf, Jr. (Butterworths Scientific Publications Ltd., London, 1962).
3 J. C. Jamieson and A. W. Lawson, J. Appl. Phys. 33, 776 (1962). 4 H. T. Hall and J. D. Barnett, Final Report OOR Project 2723-C.
29
O.OlS-in.-thick layer of pressure-fused LiH containing (1) suitable platinum collimation, (2) a O.090-in.-diam central disk of 85% boron-15% LiH, and (3) the sample to be studied.
The platinum collimators are lightly glued to a flat piston. There are three parts to the collimation. (a) The entering beam is collimated by means of 0.016-in.-diam platinum wire, glued lightly to the flat piston at a distance of 0.060 in. from the center and with an opening of 0.025 in. (b) X rays are prevented from bypassing the sample by a 0.016-in.-diam platinum wire with central part flattened to 0.005 in. thick and cut down to 0.018 in. high. The
STCCl JACKET
PYROPHILLITE SAMPLE ~ Pf:LLETS
CONTAININC DISk --&....-;;:: ~ THREAOEO~ ~
INSERT ~ §lJ
FIG. 1. Exploded view of x-ray cell.
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30 PEREZ-ALBUERNE, FORSGREN, AND DRICKAMER
TABLE I. Materials and dimensions for x-ray cell (all dimensions are in inches).
t Cell ! Cell
Outer jacket
Material AISI4340 AISI4340 Hardness 42-44R.C. 42-44 R.C.
o.d. 2.255 2.255 Ld. 1.744 1.496
Height ! ! Diameter of
entrance hole t t Height of slot .! t •
Inner Jacket
Material Crucible Labelle HT Crucible Labelle HT Hardness 49-51 R.C. 49-51 R.C.
o.d. 1.7500 1.500 Threads 1-1-24 TPI !-28TPI
Height 3 .a .- • Diameter of entrance hole 3 -h 12
Height of slot 3 3 12 12
Rings
Material Crucible Labelle Crucible Labelle HT steel HT steel
Hardness 50-52 R.c. 50-52 R.C. i.d. 0.8755 0.5005
Threads 11-24 TPI !-28 TPI Height .a .a
8 • Inlet slot 0.040XO.020 high 0.040XO.015 high Height of outlet
slot 0.020 O.ot5
Pistons
Material Grade 999 Carboloy Grade 999 Carboloy Length It It Diameter 0.875 0.500 Taper 18° 18° Flat diameter 0.045 0.045
Jackets
o.d. 11 Ii i.d. 0.870 0.497 Height *
!l. • LiHLoad 110-120 mg 30-35 mg
central spacing is 0.014 to 0.015 in. (c) The exit beam is removed through a channel between two 0.016-in.-diam wires lightly glued to the flat piston so that the ends lie just outside the O.090-in. central circle. The distance
LiH
LiH
Fw. 2. Detail of LiH disk.
between the wires is 0.015 to 0.017 in. at the center and 0.060 in. at the outside of the half-inch pistons (0.090 in. at the outside edge of the i-in. pistons). The collimation around the sample is particularly important. It is absolutely necessary to insure that none of the boron mixture discussed below remains fused above or below the 0.005-in.-thick sections of platinum on either side of the sample.
(2) Two half-disks of pyrophyllite of 0.090-in. diameter and 0.015 in. thick are placed around the center collimators. LiH is added (for amounts see Table I). The flat piston is inserted in the cell so that the pellet can be formed above the slot. The material is pressed to an average pressure of 6 to 8 kilobars using a second flat piston.
(3) The pyrophyllite in the center is removed quantitatively and two semicircular disks of 85% boron and 15% LiH are inserted. The boron-LiH disks are made by pressing 4.5 mg of the mixture into a 0.090-in.-diam hole in a flat piece of pyrophylIite. The pyrophyllite is initially 0.025 in. thick. The material is repressed to 10 to 14 kilobars with the fiat pistons. Boron has much better friction than LiH. The mixture fuses much better than pure boron and permits subsequent operations to be performed much more reproducibly.
(4) Using a guide carefully machined to fit the cylinder, a 0.015-in. hole is drilled at the center for the sample. As discussed below, the sample generally contains a marker and may be diluted with boron. It is inserted through the guide into the hole a little at a time, tamping each loading in place.
Some samples are prefused into pellets and one or more of these are forced into the hole for the sample. The proper dilution of the sample and the best detailed method of inserting it is a matter which requires considerable experience for each new material. Mter the sample is inserted, the entire disk is repressed with flat pistons to 16.5 kilobars average pressure.
(5) The flat pistons are removed, the tapered pyrophyllite pellets are inserted, and, using appropriate shims on the bottom piston, the disk is pressed until it is opposite the slot. (Actually it is usually placed 0.002 to 0.004 in. above the center to allow for deformation of the bottom piston.) The cell is now put in the press which is identical with the press used for optical work! except that provision is made for detection around a maximum angle of 135°. The press is carefully centered above a Phillips goniometer for use in one of the two detection methods discussed below.
The source is a Philips molybdenum target tube (with 0.004-in. zirconium filter) in a portable tube mount which can be accurately positioned from run to run. Two detection systems are used. The outside cell diameter is the same as the 57.3-mm powder camera, so a film may be wrapped on the outside and exposed for a time determined by experience (t to 4 h). More usually, a photomultiplier
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HIGH PRESSURE X-RAY MEASUREMENTS 31
X-RAY TUBE
MOUNTINC
SCINTILLATION COUNTER
SCI NTI LLATION COUNTER
J BRA55TU~
o FIG. 3. Experimental arrangement. c;::=~~=---ROTATINC ARM
X-RAY TUBE MOUNTINC
(bl OETAIL OF CELL ARRANCEMENT
(Ql OVER-ALL VIEW
detector is used mounted on the goniometer. The geometry is shown in Fig. 3. The electronic system is standard. This latter system is advantageous as only the region of a few strong peaks on the sample and on the marker need be scanned so that the time at anyone pressure is markedly reduced.
As mentioned above, the sample is usually studied in the presence of a marker (a material of known compressibility) so that the pressure can be determined. Since samples vary over wide ranges of compressibility and since they occupy a significant fraction of the central section, it is necessary to determine pressures at each applied force for each new material. Silver, rhodium, and palladium have been generally used as markers to date, but other materials will also prove useful. These materials were selected because they have cubic close packed structure and are unlikely to undergo phase transitions, because they have favorable characteristics for use with molybdenum radiation, and because their densities as a function of pressure have previously been determined by shock wave measurements.5,6
It is not the purpose of this paper to discuss results extensively. A few data are given to illustrate the range and reproducibility of the technique. Figures 4 to 6 show the average applied pressure on the piston versus pressure on the sample for silver, rhodium, and palladium. The sample pressures were obtained from the measured change in lattice parameter and the volume changes obtained in shock wave measurements as listed in Table II. The lines used were generally the (111), (200), (220), and (311) lines.
5 M. H. Rice, R. G. McQueen, and J. M. Walsh in Solid State Physics, edited by F. Seitz and D. Turnbull (Academic Press Inc., New York, 1958), Vol. 6.
6 R. G. McQueen and S. P. Marsh, J. Appl. Phys. 31,1253 (1960).
No consistant variation in lattice parameter was obtained from different lines. The samples were diluted with boron, the usual sample containing 20 to 50% of the material being studied.
Several points can be noted from the curves. In all cases the maximum pressure range is somewhat over 500 kilobars. In all cases the slope of the sample pressure versus applied pressure curve is markedly less at high pressure than at low. (The straight lines drawn through different parts of the data are to indicate the general slopes in
500
400
200
100
24 28
FIG. 4. Pressure on sample (from change of lattice parameter) vs average applied pressure--silver.
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32 PEREZ-ALBUERNE, FORSGREN, AND DRICKAMER
500
400
°
/ /
o/.
4 8 ~ ~ m ~ a APPLIED PRESSURE (KBARS)
FIG. 5. Pressure on sample (from change of lattice parameter) vs average applied pressure-rhodium.
different regions. No linear calibration is used.) With the use of a marker in studying any new material it is not necessary that loadings be absolutely reproducible, but one sees that the degree of reproducibility is reasonable. As a matter of fact, although there is a significant difference in compressibility for the three metals, the three curves of pressure versus applied force are rather similar.
Figure 7 shows fractional change in lattice parameter versus pressure for CsCl. Most data were taken with a
Ul II: « III ,S W II: :::> ell ell W a: 11.
I o 4
o
•
I •
I
612162024 APPLIED PRESSURE (KBARS)
28
FIG. 6 Pressure on sample (from change of lattice parameter) vs average applied pressure-palladium.
T ABLE II. P-V data used in establishing pressure."
VIVo P(kilobars) Ag Rh Pd
0 1.0000 1.0000 1.0000 100 0.9273 0.9680 0.9507 150 0.9012 0.9541 0.9308 200 0.8788 0.9413 0.9140 250 0.8594 0.9294 0.8990 300 0.8420 0.9181 0.8862 350 0.8262 0.9077 0.8743 400 0.8122 0.8978 0.8636 450 0.7987 0.8884 0.8536 500 0.7866 0.8797 0.8444 600 0.7640 0.8641 0.8280
• From data of Ref. 5 and 6. interpolated to 20°e.
silver marker, but one run was made with rhodium, and several to modest pressure with molybdenum. The data are quite reproducible. A detailed discussion of these results, along with other alkali halide data, will be presented elsewhere. However, it is of interest to point out that the dotted curve represents an extrapolation of Bridgman's data,1 using a Murnaghan-type equationS of the form
p= 24.4[(V /VO)6.14_1], (1)
where p is in kilo bars. Our results show slightly less compressibility in the low
pressure region and a significantly greater compressibility at high pressure. The total compression at the highest point represents a volume 57.2% of the atmospheric volume, so that relatively high pressures can be reached with compressible materials.
Some effort has been made to run two markers together in a single load. To pressures of over 300 kilo bars the
did'
1.0Ir--r--r--.---,...----.--r--r--,...---,.--.--...,.......,
II 0.91 \
0.91 \
0.9<
0.9<
0.9<
0.88
0.84
o
'\ '\ .s
\<>1 ~.
~ ......... . ),~
•• A ••
A
EQ. (I)
Aq MARKER Rh MARKER Mo MARKER
'h":--... i 00_ I .""'-- __ .0 ••
o
100 200 300 400 PRESSURE rKBARSl
FIG. 7. Fractional change in lattice parameter vs pressure-CsC!.
500
7 P. W. Bridgman, Proc. Am. Acad. Arts and Sci. 76, 1 (1945). 8 F. D. Murnaghan, Finite Deformation of an Elastic Solid (John
Wiley & Sons, Inc., New York, 1951).
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HIGH PRESSURE X-RAY MEASUREMENTS 33
pressures obtained from different markers in the same load were the same. This result, and the fact that CsCl compressibilities obtained with different markers were the same, indicate a high degree of internal consistency for the shock wave data, at least for the substances we have studied.
As can be seen from Figs. 4 to 6, the average appEed pressure never exceeded 30 kilobars. The pistons apparently seldom if ever break on application of pressure, but always on release. While there is some problem of deformation of the inner ring after long times at high pressure, there is no problem of extrusion of LiH or of breakage of the cell. The limiting factor is the cutting off of the x rays
THE REVIEW OF SCIENTIFIC INSTRUMENTS
due to bowing of the flats. The piston tips, when recoverable, are dented several thousandths of an inch, and the reversible deformation must be considerably more. It might be possible to extend the pressure range by replacing the tips by suitably ground diamonds. For some experiments the added expense might be warranted by the possible extension of the pressure range.
The authors wish to thank J. C. Jamieson of the University of Chicago for the helpful discussions, and W. B. Daniels of Princeton University for useful suggestions. R. L. Clendenen collaborated in the latter phases of the development of the cell. The patient and careful machine work of W. W. Demlow was invaluable.
VOLUME 35. NUMBER 1 JANuARY 1964
Magnetization and a Superconducting Solenoid*
PAUL R. ARONt
Lawrence Radiation Laboratory, University of California, Berkeley, California
(Received 19 August 1963; and in final form, 9 October 1963)
The relationship of the magnetization of Nb-250/0 Zr superconducting alloy and the magnetic field of a solenoid constructed of this material is discussed. Measurements of the magnetic field as a function of current, induced magnetic moment, history-dependent remanent moment, and other related properties are described. An approximate method of computing the magnitudes of these effects is discussed and the results are shown to agree with measurements. The coil critical current Ie is related to the short sample Ie, and the discrepancy is discussed in terms of the magnetization of Nb-Zr.
INTRODUCTION
IN 1961 Kunzlerl and others2 demonstrated the existence of superconducting materials with high critical fields
associated with high transport currents. Since that time there has been a concerted effort to construct magnets with volumes and fields appropriate for research in physics. Published and unpublished reports indicate that a large measure of success has been achieved. Magnets with fields as high as 68 kG over a diameter of ! in. have been reported.a Magnets of lower fields (40 to 50 kG) but of larger diameter (2.5 to 5 in:) have also been described.4•5
It would seem appropriate, then, to ask detailed questions
* Work done under the auspiecs of the U. S. Atomic Energy Commission.
t Present address: NASA, Lewis Research Center, Cleveland, Ohio. 1 J. E. Kunzler, E. Buehler, F. S. L. Hsu, and J. H. Wernick,
Phys. Rev. Letters 6, 39 (1961). 2 T. G. Berlincourt, R. R. Hake, and D. H. Leslie, Phys. Rev.
Letters 6, 671 (1961). 3 J. E. Kunzler in Proceedings of the 1961 International Conference
on High Magnetic Felds (M.LT. Press and John Wiley & Sons, Inc., New York, 1962), p. 574.
4 J.K. Hulm, M. J. Fraser, H. Riemersma, A. J. Venturino, and R. A. Wien in Proceedings of the 1961 International Conference on High Magnetic Fields (M.LT. Press and John Wiley & Sons, Inc., New York, 1962), p. 332.
5 R. C. Wolgast, H. P. Hernandez, P. R. Aron, H. C. Hitchcock, K. A. Solomon, Advan. Cryog. Eng. 8 (1963).
as to the nature of the field in the magnet. For example: how does it depend on the current, or what is the spatial distribution of the field in the bore of the magnet? This investigation was undertaken in an attempt to reveal the magnitude of the deviations of the magnetic field from classical behavior. The deviations to be discussed result from the nature of the magnetization of the superconductor.
Figure 1 shows typical behavior in the M -H plane of a long cylindrical sample of class II superconducting heavily cold-worked alloy, Nb-2S%Zr, in a magnetic field parallel to its axis. Several features should be noted. First, there is the region of apparent perfect diamagnetic behavior,6 which extends to 470 G, where flux begins to enter. Then the magnetization follows a roughly parabolic curve until at about 8 kG a flux jump occurs. This is a discontinuity in the magnetization curve that is associated with the evolution of heat,7 presumably as the result of eddy current losses in the normal regions of what must be a kind of intermediate-state structure. Then the behavior is repeated with varying deviation from the )l= 1 line until a field
• H. C. Hitchcock, Lawrence Radiation Laboratory, Berkeley, California, (private communication, 1963).
7 Y. B. Kim, C. F. Hempstead, and A. R. Strnad, Phys. Rev. Letters 9, 306 (1962).
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