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Metallurgical examination of the LAMPF beam stop

Conference · · Trans. Am. Nucl. Soc.; (United States)
OSTI ID:7142377

The Clinton P. Anderson Los Alamos Meson Physics Facility (LAMPF) provides physicists with 800-MeV protons and secondary particles with which to perform nuclear physics and other experiments. The secondary particles are generated by the interaction of the proton beam with graphite targets in the experimental area. Passage through these targets and those of the isotope production facility reduces the proton energy to approx. 500 MeV and spreads the beam out. At the face of the beam stop, the beam is believed to have a roughly Gaussian profile, with a full-width at half-maximum of approx. 60 mm. Allowing for beam attenuation in upstream targets, the power deposition in the beam stop is approx. 375 kW. In this paper, we report the results of metallographic examination of a beam stop that was used at LAMPF for approx. 3 yr. Examination of the copper plates and the Alloy 718 front plate shows that while both materials have become less ductile, only the copper plates have been sufficiently embrittled (along the grain boundaries) to lead to the breakup of the plates. The integrity of the beam stop system depends primarily on the condition of the front plate, which is the area of the pressure vessel most exposed to radiation damage. The tensile properties of the Alloy 718 sample tested indicate that the front plant of the beam stop should remain intact at similar proton doses. At present beam currents, this requires replacement of the beam stop approximately every 2 yr.

Research Organization:
Los Alamos National Lab., NM (USA)
OSTI ID:
7142377
Report Number(s):
CONF-8711195-
Journal Information:
Trans. Am. Nucl. Soc.; (United States), Journal Name: Trans. Am. Nucl. Soc.; (United States) Vol. 55; ISSN TANSA
Country of Publication:
United States
Language:
English