Activation Products from Copper and Steel Samples Exposed to Showers Produced by 8 GeV Protons Lost in the Fermilab Main Injector Collimation System

TL;DR

This study investigates residual radioactivity in copper and steel samples exposed to proton showers in Fermilab's Main Injector, identifying additional isotopes and comparing measurements with simulation models to predict long-term radiation concerns.

Contribution

It provides new activation data for materials near the Fermilab collimation system and improves isotope identification for residual radiation prediction.

Findings

Identification of additional radioactive isotopes

Comparison of measurements with MARS15 simulations

Implications for long-term radiation management

Abstract

In conjunction with efforts to predict residual radiation levels in the Fermilab Main Injector, measurements of residual radiation were correlated with the time history of losses. Detailed examination suggested that the list of radioactive isotopes used for fitting was incomplete. We will report on activation studies of magnet steel and copper samples which we irradiated adjacent to the Fermilab Main Injector collimation system. Our results identified several additional radioactive isotopes of interest. The MARS15 studies using a simplified model are compared with measurements. The long half-life isotopes will grow in importance as operation stretches to a second decade and as loss rates rise. These studies allow us to predict limits on these concerns.