This document discusses the implications of various collective phenomena on the required performance of candidate lattices for the LBL 1 to 2 GeV Synchrotron Radiation Source. The performance issues considered include bunch length, emittance growth, and beam lifetime. In addition, the possible use of the 1 to 2 GeV Synchrotron Radiation Source as a high-gain FEL is explored briefly. Generally, the differences between lattices are minor. It appears that the most significant feature distinguishing the various alternatives will be the beam lifetime.

We have made preliminary neutron-capture cross-section calculations of the Hauser-Feshbach type for the isotopes /sup 144/Sm, /sup 145/Sm, and /sup 145/Pm to investigate the production of radioactive /sup 145/Pm by neutron capture on the stable isotope /sup 144/Sm. The calculations were made for incident neutron energies from 2.5 MeV to about 1/sup -4/ or 10/sup -5/ MeV, wherever the first unbound resonance was estimated to occur in each case. At that energy, the calculated value was reduced by a somewhat arbitrary factor, and the excitation function extended down to thermal energy using a (E/sub n/)/sup -1/2/ energy dependence. Since very large uncertainties are associated with the position and magnitude of the first unbound resonance and the subsequent extrapolation back to thermal energy, the cross sections in this low-energy region should not be considered more accurate than +- a factor of 10. For incident neutron energies above each step, the calculations represent an average through the separated and overlapping resonance regions and may be accurate to better than +- a factor of 2. 18 refs., 7 figs., 5 tabs.

The original microchannel plates have been damaged in the beam region. After an attempt to revive the plates by baking, the gain of the central 30mm is still reduced by approximately a factor of three. The plates appear to have been irreversibly damaged by being operated for an extended period of time at high gain with high debuncher beam currents. A new set of microchannel plates has been installed in the monitor. Because of a production error, the gap between the microchannel plate output and the anode wire plane was set at 15mm instead of 3mm. The high voltage divider allowed a maximum of 170 volts to be applied across this gap. Under the conditions at which the Monitor was being operated, the distribution of collected electrons from a single micro channel was spread over a large area. A collimated UV light source which had a FWHM of 3mm produced a profile with a FWHM of 22mm with an amplifier threshold supply voltage of 1.0 V and FWHM of 9mm with a threshold voltage of 5.0V. See Figure 1. When new microchannel plates were installed, the anode gap was reduced to 9.5mm, and the gap voltage was increased to 760V, …