Hydrodynamic Penetration of High Power Particle Beams
Abstract
A high power particle beam that dwells on a target can produce hydrodynamic effects if the energy deposition exceeds a threshold needed to vaporize the target (typically a few kJ/g). If lateral hydrodynamic expansion causes decompression during the pulse, the beam can penetrate much farther than expected. By combining the MARS energy deposition code with 2- and 3-D hydrodynamic codes (MESA and SPHINX) we have calculated the effects of high power beams in abnormal situations. A 20 TeV proton beam with σ_x=σ_y=2 mm, 4×10^14 ppp, 290μs,which strikes the face of a 4×7×800 cm graphite block, simulating a beam dump, creates a hole that expands laterally at 0.02cm/μs and longitudinally at 10cm/μs . If the beam is scanned across the face of the block at >=1mm/μs the beam moves into fresh material fast enough that there is no additional penetration beyond the static range. Proton interactions with a scraper were simulated with a σ_x=σ_y=0.2 mm beam propagating 1 or 2σ from a steel slab. A low density groove propagates parallel to the beam in the steel at about 60cm/μs, creating temperatures of 7000^circC and pressures of 25 kbar. Simulation of a superconducting magnet section produces similar temperatures and densities in the blowoff. Energy deposition in the superconducting coils reaches 25 J/g by 6μs and the beam tube reaches 1500^circC. These calculations illucidate abnormal scenarios to be avoided in accelerator design.
- Publication:
-
APS April Meeting Abstracts
- Pub Date:
- April 1998
- Bibcode:
- 1998APS..APR.D1705W