Physics Division 1996 to 1998
Physics Division 1996 to 1998The two primary and related activities of this group of the Physics Division are the WA98 experiment at CERN and the construction of the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory (BNL). The ORNL High-Energy (nuclear) Reactions Group (HERG) plays key roles in both of these large collaborative ventures, and HERG staff members are in leadership positions in both experiments. Terry Awes continues as Spokesman of WA98, which is the last of the "WA" series of heavy-ion CERN experiments (WA80, WA93, and WA98), in which ORNL has participated since their inception in January 1984. In PHENIX, Glenn Young continued as Deputy Spokesman. Glenn also continues to have responsibility for all PHENIX "on-line" systems, including front-end electronics, trigger, and on-line computing, although with the approach of first running of PHENIX, considerable responsibility for on-line installation and commissioning has been handed to BNL and Nevis personnel. Ken Read is subsystem manager for the mechanics of the PHENIX muon identifier; Vince Cianciolo is subsystem manager for the electronics of the muon identifier; Terry Awes is subsystem manager for the lead-glass EM Calorimeter (EMCal); and Paul Stankus is subsystem manager for all electronics for EMCal.
This reporting period represents the peak of analysis activity for the WA98 experiment. The third and final run with heavy ions was performed in October-November 1996, just at the start of the range of this report. The 1996 run was very productive, and the data appear to be of high quality. Both tracking arms were finally present for the second half of the 1996 run. Analysis activities are in full swing, with ten papers in preparation, submitted, or published. Following the 1995 run, efforts focused on the implementation of a second tracking arm. The commissioning of the second arm was also important for PHENIX prototype and "checkout" activities, since the "pad-chambers" of the second arm were PHENIX prototypes. The time-of-flight system and the Kurchatov-Muenster-ORNL 10,000-module lead-glass detector, commissioned in 1994, have both since been transported to PHENIX, rearranged and commissioned on site at BNL, and installed into PHENIX.
The acceleration of PHENIX activities continued, and most resources of the group are being dedicated to this effort. ORNL led construction and installation of the muon identifier subsystem, which was completed in September 1998. Close collaboration continues with the Instrumentation and Controls Division on a number of PHENIX front-end electronics projects; ORNL is responsible for half of the front-end electronics systems in PHENIX. ORNL staff members are also involved in the lead glass portion of the electromagnetic calorimeter which, as mentioned above, has been moved from CERN and reinstalled in PHENIX. The large number of ORNL responsibilities in PHENIX have placed a considerable strain on the manpower resources of the section. Three younger staff members on term appointments were added to help meet commitments (F. Bellaiche and Y. Efremenko on the muon identifier and S. Belikov on EMCal electronics).
During this reporting period a new exploratory project, supported with Laboratory discretionary funds, was initiated in collaboration with the University of Tennessee (UT) under the leadership of Yuri Efremenko. Its purpose is to search for neutrio oscillations, using the intense flux of neutrinos which will be produced from the production targets of the Spallation Neutron Source (SNS). A search with more than an order of magnitude better sensitivity than previous ones becomes possible at the SNS. The evidence presented during 1998 by the Super Kamiokande experiment for flavor oscillation of atmospheric muon neutrinos makes the case for accelerator-based searches quite compelling. This effort has since resulted in formation of a collaboration known as ORLaND, headed by Professor Frank Avignone of the University of South Carolina. A proposal has been developed and submitted to ORNL management for review during FY 1999. Submission of a proposal to DOE's Office of High Energy and Nuclear Physics for construction and operation of the experiment is planned subsequently. The SNS itself was approved and construction began during FY 1998.