Booster Activation History

These pages present Booster activation data collected during access periods since June 2001. The data camprises LSM measurements of dose rates at fixed points around Booster ring. Where possible each measurement is made at contact with the surface of the beam pipe. However at the RF stations the measurements are made at 1 foot from the cavity surface.

Since these radiation surveys take place at varying times after the beam has been shut off, an attempt has been made to correct for the varying amounts cooldown. To determine the size of the corrections we attempted to measure cooldown rates during an extended shut down from Jan 13 to Jan 27, 2003. The results from each measurement location were normalized to provide an average of one. The average and RMS of each set of measurements was then plotted against the number of hours since the beam had been shut off. To this data we added a long timescale measurement which was derived from activation measurements made at the start and end of the long shutdown in 2003. These results were fitted with both a single and a double exponential. The data and fits are shown here. For the double exponential fit, the half life of 54Mn (303 days) was used for the longer lived decay term. However, equally good fits could be obtained using either 57Co (282 days) or 22Na (2.6 years). The best fit required a half life of 5.6 days for the second term which is very close to the half life of 18F (5.7 days). Thus we use 5.7 days for the second term. The parameters of the double exponential fit were used to apply a cooldown correction to the activation data. The correction factors scale the data to what we would expect after a one hour cool down. Note, however, that the cooldown rate is quite slow and hence this correction is not particularly important.

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