TEMPERATURE RISE MEASUREMENTS FOR A SIMPLE MERCURY TARGET EXPOSED TO PROTON BEAMS

摘要

A specially designed and instrumented mercury target vessel was used to evaluate the energy distribution resulting from the interaction of a proton beam with a mercury target. The information obtained will be used to validate computer models being used to design the Spallation Neutron Source (SNS) target. The tests were performed at the Los Alamos Neutron Science Center Weapons Neutron Research facility in Los Alamos, New Mexico, in August 2000. In the SNS, intense thermal shock loads are expected to cause an enormous rate of temperature rise (～10{sup}7 K/s), resulting in pressure waves in the mercury that may lead to large stresses on the thin walls of the mercury vessel. To guide the mercury target design and to benchmark the computer design codes, the energy deposition was measured throughout the target. Three types of sensors were used to measure the temperatures: type K thermocouples, FISO Fabry-Perot sensors, and phosphor thermometry sensors. Part of the purpose of the experiments was to evaluate the FISO and thermographic phosphor sensors for use in a proton beam environment. Both sensors performed well, although the FISO sensors proved to be somewhat fragile. The 800-MeV beam deposited protons at levels of 2.84 H 10{sup}13, 1.48 H 10{sup}13, and 7.22 H 10{sup}12 protons per pulse. The vessel was 97.3 mm (3.83 in.) in diameter and 203 mm (8 in.) long. The peak temperature rise was approximately 10 K for the highest energy deposition.