STP956

    Operating Experience at the Los Alamos Spallation Radiation Effects Facility at LAMPF

    Published: Jan 1987


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    Abstract

    Operation of a new irradiation facility at the beam stop (Target Station A-6) at the Clinton P. Anderson Los Alamos Meson Physics Facility (LAMPF) began in May 1985. The facility is now fully operational. A closed-loop water system, a closed-loop helium system, remote handling procedures for activated materials, experiment change-out procedures, and experiment control equipment are all in place.

    Experience dictated a change in irradiation capsules from a system that used metal seals to a system that is completely welded. The seals were found to be unreliable and difficult to replace by remote means.

    Several materials have been irradiated in the direct 760-MeV proton beam. Material property changes as well as helium production in a variety of materials are being investigated.

    A special sample holder that can accommodate transmission electron microscopy (TEM) specimens, isolate them from the cooling medium, maintain fixed temperature, and retain essentially a stressfree state has been developed. Remote handling retrieval of these specimens is being developed.

    Activation foil measurements are being made to determine the secondary particle flux and spectrum (charged particles and neutrons) that result from interaction of the direct proton beam with targets at the beam stop. Twelve independent irradiation ports, each with an irradiation volume of 0.12 by 0.25 by 0.50 m, are available for exposing material to this particle flux, primarily neutrons. Two irradiations were completed in this area during the period May through December 1985. The neutron spectrum here resembles a fission spectrum with the addition of neutrons in the MeV energy range (high-energy tail). The maximum neutron flux is about 6 × 1017 n/m2 s at one of the 12 ports and drops by a factor of about 10 as a minimum at another of the 12 ports.

    Three independent ports for proton irradiations are in place. Each has an irradiation volume of about 150 cm3. The proton beam has a Gaussian intensity profile; the maximum proton flux at the center of the beam is 1.2 × 1014 protons/cm2 · s. The beam spot has a diameter of approximately 5 cm at 2σ. Four irradiations were completed in this area during the period May through December 1985.

    Keywords:

    protons, spallation neutrons, irradiation facility, irradiation techniques, Los Alamos Meson Physics Facility (LAMPF)


    Author Information:

    Sommer, WF
    Associate group leader, senior technician, and senior designer, Los Alamos National Laboratory, Los AlamosNM,

    Lohmann, W
    Research scientist and engineer, KFA Jülich GmbH, Jülich,

    Graf, K
    Research scientist and engineer, KFA Jülich GmbH, Jülich,

    Taylor, IK
    Associate group leader, senior technician, and senior designer, Los Alamos National Laboratory, Los AlamosNM,

    Chavez, RM
    Associate group leader, senior technician, and senior designer, Los Alamos National Laboratory, Los AlamosNM,


    Paper ID: STP25687S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP25687S


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