Detecting cavitation in mercury exposed to a high-energy pulsed proton beam

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Journal of the Acoustical Society of America

DOI:https://doi.org/10.1121/1.3353095· OSTI ID:976043

Manzi, Nicholas J ^[1]; Chitnis, Parag V ^[1]; Holt, Ray G ^[1]; Roy, Ronald A ^[1]; Cleveland, Robin O ^[1]; Riemer, Bernie ^[1]; Wendel, Mark W ^[1]

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1. ORNL

The Oak Ridge National Laboratory Spallation Neutron Source employs a high-energy pulsed proton beam incident on a mercury target to generate short bursts of neutrons. Absorption of the proton beam produces rapid heating of the mercury, resulting in the formation of acoustic shock waves and the nucleation of cavitation bubbles. The subsequent collapse of these cavitation bubbles promote erosion of the steel target walls. Preliminary measurements using two passive cavitation detectors (megahertz-frequency focused and unfocused piezoelectric transducers) installed in a mercury test target to monitor cavitation generated by proton beams with charges ranging from 0.041 to 4.1 C will be reported on. Cavitation was initially detected for a beam charge of 0.082 C by the presence of an acoustic emission approximately 250 s after arrival of the incident proton beam. This emission was consistent with an inertial cavitation collapse of a bubble with an estimated maximum bubble radius of 0.19 mm, based on collapse time. The peak pressure in the mercury for the initiation of cavitation was predicted to be 0.6 MPa. For a beam charge of 0.41 C and higher, the lifetimes of the bubbles exceeded the reverberation time of the chamber (~300 s), and distinct windows of cavitation activity were detected, a phenomenon that likely resulted from the interaction of the reverberation in the chamber and the cavitation bubbles.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 976043
• Journal Information: Journal of the Acoustical Society of America, Journal Name: Journal of the Acoustical Society of America Journal Issue: 4 Vol. 127; ISSN 0001-4966; ISSN JASMAN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION
ACOUSTICS
BUBBLES
CAVITATION
HEATING
MERCURY
MONITORS
NEUTRON SOURCES
NEUTRONS
NUCLEATION
ORNL
PROTON BEAMS
SHOCK WAVES
SPALLATION
STEELS
TARGETS
TRANSDUCERS
acoustic
cavitation
detection
mercury
spallation
target