Measurement of an equation-of-state point for molybdenum at very high pressure

Conference · Thu Jan 01 04:00:00 EST 1976

OSTI ID:7128701

Ragan, III, C E; Silbert, M G; Diven, B C

A shock was generated by rapidly fission heating a slab of /sup 235/U by exposing it to neutrons at approximately 1 m from a nuclear explosion and allowing it to expand into an adjacent sample of the material to be studied. A point on the molybdenum equation of state was determined at a pressure of 2.0 TPa (20 Mbar) by measuring directly both the shock velocity and the particle velocity behind the shock. The shock velocity was obtained by measuring the transit time of the planar shock between positions at two depths in the molybdenum. This time interval was determined by observing the light flashes produced when the shock reached free surfaces located at the two depths. The particle velocity was obtained by observing the Doppler shifts of six neutron resonances in the neutron energy region from 200 to 800 eV in the moving, shocked molybdenum. The pressure and density derived from this pair of velocity measurements, made to an accuracy of +- 5 percent, are 20 Mbar and 25 g-cm/sup -3/, respectively. This experiment represents the first direct determination of a point on the equation-of-state of any material in this pressure region, and the resulting data point is in good agreement with theoretical estimates. It appears that errors in both the shock velocity and the particle velocity can be reduced to approximately +- 2 percent in an improved measurement, resulting in a well-defined point on the equation of state for molybdenum, which can be used as a standard in future impedance-matching experiments.

• Research Organization: Los Alamos Scientific Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 7128701
• Report Number(s): LA-UR-76-2286; CONF-761127-4
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
BARYONS
DOPPLER EFFECT
ELEMENTARY PARTICLES
ELEMENTS
EQUATIONS
EQUATIONS OF STATE
FERMIONS
HADRONS
METALS
MOLYBDENUM
NEUTRONS
NUCLEONS
REFRACTORY METALS
RESONANCE NEUTRONS
SHOCK WAVES
TRANSITION ELEMENTS
VELOCITY
VERY HIGH PRESSURE