PREFACE
The original Conceptual Design Report was submitted to the BNL-AGS Program Advisory Committee in October 1994. It was presented to the Physics Advisory Committee in April 1995 with the result that BRAHMS received full scientific approval from them. The present report is intended to provide an update of the October 1994 version, indicating specifically the consequences and advantages of the decision to site BRAHMS at the 2-O'clock area. Thus, much of the discussion of problems specific to the 4-O'clock location (such as the R-F interference) are no longer germane. We have retained the original text for Chapter 5, but have expanded the description of the 2-O'clock area (Section 5.7) in order to indicate more clearly just how BRAHMS fits into that location. Significant advantages, as well as specifics of shielding and general operation, are enumerated. Additional tests of the Prototype Rich Detector (referenced at the end of Appendix A) are particularly encouraging. Measurements with a pure C4F10 radiator confirm the predicted imaging capabilities of the device, and result in the estimate N_0=100 +- 10 cm**-1. This is quite close to the expected Figure-of-Merit based on manufacturers specifications. This work is supported in part by the U.S. Department of Energy, Division of Basic Energy Sciences under Contract No. DE-AC02-76CH00016.