Production of diamond using intense heavy ion beams at the FAIR facility and application to planetary physics

Abstract

Diamonds are supposedly abundantly present in different objects in the Universe including meteorites, carbon-rich stars as well as carbon-rich extrasolar planets. Moreover, the prediction that in deep layers of Uranus and Neptune, methane may undergo a process of phase separation into diamond and hydrogen, has been experimentally verified. In particular, high power lasers have been used to study this problem. It is therefore important from the point of view of astrophysics and planetary physics, to further study the production processes of diamond in the laboratory. In the present paper, we present numerical simulations of implosion of a solid carbon sample using an intense uranium beam that is to be delivered by the heavy ion synchrotron, SIS100, that is under construction at the Facility for Antiprotons and Ion Research (FAIR), at Darmstadt. These calculations show that using our proposed experimental scheme, one can generate the extreme pressure and temperature conditions, necessary to produce diamonds of mm³ dimensions.

Figure 1

Carbon phase diagram (P–T), showing the area accessible using the FAIR facility. For comparison, the isentrope of Uranus (green line), the Earth geotherm (light blue line) and the compression path of a single shock (blue line) using the SESAME database, are included.

Figure 2

Overview of the FAIR (red) and GSI (blue) accelerator complex. The HED target station is located in a multi-purpose fully-shielded building: the APPA cave. CBM Compressed Baryonic Matter experiment, NUSTAR NUclear STructure Astrophysics and Reactions, PANDA antimatter research. APPA Atomic, Plasma Physics and Applications.

Figure 3

Beam–target set up of the LAPLAS scheme using an annular focal spot.

Figure 4

Cross sectional view of the LAPLAS target.

Figure 5

Beam–target set up of the LAPLAS scheme using a circular focal spot.

Figure 6

Initial target density distribution generated by BIG2 code.

Figure 7

Target physical conditions generated by the BIG2 code at t = 100 ns, sample radius R${}_{\mathit{si}}$ = 0.5 mm, outer target radius, R${}_o$ = 5 mm, target length = 7 mm, bunch intensity = 3 × 10¹¹ uranium ions, bunch length = 200 ns, ion energy = 2 GeV/u, (a) specific energy, (b) temperature, (c) pressure and (d) density.

Figure 8

Same as in Fig. 6, but at t = 200 ns (end of the ion bunch).

Figure 9

Density vs radius at different times at the middle of the axis.

Figure 10

Achieved physical conditions at t = 270 ns.

Figure 11

Achieved density, temperature and pressure profiles at t = 270 ns, (a) along radius at the middle of the axis and (b) along the axis (r = 0).

Figure 12

Density, temperature and pressure along axis at t = 270 ns, (a) target length = 3 mm, (b) target length = 4 mm, (c) target length = 5 mm and (d) target length = 6 mm.

Figure 13

(top) Schematic of the proposed set up for on-axis radiographic imaging using a laser-driven X-ray source, and (bottom) simulated radiographic images of (a) the initial target, (b) after compression at a time of 270 ns, and (c) central lineouts at both probe times.