Status Report for Experiment AD-4/ACE

The overall goal of the AD-4 Experiment is to study whether antiprotons might be a better tool for controlling localized cancer tumors than protons or heavy ions. This idea is based on four observations: 1. Compared with protons, the physical dose should be augmented near the end of range due to the additional energy deposited locally when antiprotons annihilate. 2. Some of the additional energy deposited results from low energy heavy ion recoils produced in the annihilation event, which are expected to exhibit a high biological efficiency. 3. Antiprotons deposit less energy than heavy ions in the entrance channel. 4. Pions and high-energy photons generated in the annihilation events can be used to detect in real time the exact location of the treatment. This report describes progress to date and highlights critical issues in combining independent measurements into on final meta analysis