Beam loss measurements during Injection into the Advanced Photon Source Upgrade storage ring

A fiber-optic (FO) beam loss montior (BLM) system, installed along the booster to storage ring (BTS) trasnport line has been useful in identifying loss locations employing time-of-flight (TOF) analysis. The BTS BLM TOF system is comprised of a pair of rad-hard, fused-silica FO cables running along either side of the BTS line at beam elevation. In the initial configuration, we measured losses at both the upstream (US) and downstream (DS) ends of the FO cable pair. However, losses further DS along the septum and injection kicker set are also of interest. We therefore added a 20-m-length, multi-strand fused-silica FO cable bundle, replacing the DS outer FO radiator input. Thus, three of the detectors are configured at the US end of their respective FO radiators. The US detector location provides lower signal but improved spatial resolution over the DS. Loss location identification has been accomplished by inserting YAG screen flags at different positions along the BTS. We present results from studies and operations.