Radionuclides in the Cooling Water Systems for the NuMi Beamline and the Antiproton Production Target Station at Fermilab

TL;DR

This study measured radionuclide levels in Fermilab's cooling water systems, revealing how materials and deionizers influence radionuclide presence, which is crucial for radiation safety and system maintenance.

Contribution

It provides detailed measurements of radionuclides in cooling water systems at Fermilab, highlighting the impact of deionizers on radionuclide removal and residual activity estimation.

Findings

Radionuclide levels vary with materials in contact with water.

Deionizers significantly reduce 7Be residual activity.

Residual 7Be activity is about 5% without deionizers.

Abstract

At the 120-GeV proton accelerator facilities of Fermilab, USA, water samples were collected from the cooling water systems for the target, magnetic horn1, magnetic horn2, decay pipe, and hadron absorber at the NuMI beamline as well as from the cooling water systems for the collection lens, pulse magnet and collimator, and beam absorber at the antiproton production target station, just after the shutdown of the accelerators for a maintenance period. Specific activities of {\gamma} -emitting radionuclides and 3H in these samples were determined using high-purity germanium detectors and a liquid scintillation counter. The cooling water contained various radionuclides depending on both major and minor materials in contact with the water. The activity of the radionuclides depended on the presence of a deionizer. Specific activities of 3H were used to estimate the residual rates of 7Be. The estimated residual rates of 7Be in the cooling water were approximately 5% for systems without deionizers and less than 0.1% for systems with deionizers, although the deionizers function to remove 7Be from the cooling water.