Temperature measurement of high-energy-density matter generated by intense heavy ion beam

Intense heavy ion beams are an excellent tool to create large-volume samples of high energy density (HED) matter with fairly uniform physical conditions. Experimental study of matter under extreme conditions of density, temperature and pressure is of considerable interest to fundamental research in the fields of plasma physics, atomic physics, astrophysics, geophysics as well as for the inertial fusion research and its applications. Recently, a series of HED physics experiments with heavy ion beams have been carried out at the GSI-Darmstadt. In these experiments, metallic targets of macroscopic volumes were heated by intense heavy ion beams uniformly and quasi-isochorically, thereby generating high-density, high-entropy states. The heated target material was expanding isentropically, passing through many interesting physical states located in the region of boiling curve, two-phase liquid-gas and the critical point. Most of the heavy ion beam energy is deposited within 120 ns which gives a possibility of appearance of intermediate meta-stable superheated liquid states. The fundamental thermo-dynamical properties of the target were measured during the heating as well as the expansion phases. The main subject of this work is the dynamic temperature measurement of the target material in the HED physics experiments with intense heavy ion beams. In the course of this work a fast multi-channel radiation pyrometer has been developed and successfully employed in experimental campaigns. The pyrometer allows measurement of brightness temperatures at 12 wavelengths with a nanosecond temporal resolution and the micrometer spatial resolution. The brightness temperatures are obtained from analysis of the Planck radiation in visible and near-infrared spectral regions. The absolute radiation emission recorded by the pyrometer at different wavelengths allow also determination of the physical temperature using different models of spectral emissivity. In the performed HED physics experiments with heavy ion beams target temperatures varying from 1000 K to 12000 K were measured for the first time. Different materials showed different behavior of hydrodynamic expansion, clearly seen on the pyrometer records. In addition to temperature measurements, measurements of target expansion dynamics have been carried out using a backlighting/shadowgraphy system based on a streak camera. Expansion velocities up to 2600 m/s have been registered for lead and up to 1700 m/s for tungsten targets. This work presents the first experimental results on temperature measurement in HED physics experiments with intense heavy ion beams. The developed fast multichan-nel pyrometer is indispensable for the present and the future HED physics experiments at GSI. The new experimental data, …