124267104
DISCUSSION OF POSSIBLE USES OF RF BEAM STRUCTURE IN COUNTER EXPERIMENTS AT NAL.
122023821
Measurement of the double-spin asymmetry ALL for inclusive multi-γ pair production with 200 GeV/c polarized proton beam and polarized proton target
The invariant double-differential cross section, E1E2d6 delta/dp(1)3dp(2)3, and the double-spin asymmetry, A(LL), for inclusive multi-gamma pair production in which gamma-rays came from neutral mesons were measured with a 200 GeV/c longitudinally-polarized proton beam and a longitudinally-polarized proton target. Most of the multi-gamma pairs comes from two-jet type events which are sensitive to partonic interaction. The A(LL) values were found to be consistent with zero. The invariant double-differential cross section for inclusive pi0pi0 production was also measured. These measured cross sections are consistent with LUND Monte Carlo simulations. Using the LUND Monte Carlo simulation package with the Carlitz-Kaur model of spin dependent distribution functions of valence quarks, the A(LL) values have been compared with theoretical predictions of gluon polarization, DELTAG/G. The results put restrictions on the size of DELTAG/G in the region of 0.05 less-than-or-similar-to x less-than-or-similar-to 0.35.
126003037
The Meson Area at 1000-GeV
124083721
SOME ASPECTS OF TARGETING SYSTEMS FOR A SLOW EXTRACTED BEAM AT THE AGS.
53129380
Ground-water activation from the upcoming operation of MI40 beam absorber
During the course of normal operation, a particle accelerator can produce radionuclides in the adjacent soil and in the beam line elements through the interactions of accelerated particles and/or secondary particles produced in the beam absorbers, targets, and sometimes elsewhere through routine beam losses. The production and concentration of these radionuclides depends on the beam parameters such as energy, intensity, particle type, and target configuration. The radionuclides produced in the soil can potentially migrate to the ground water. Soil activation and migration to the ground water depends on the details of the local hydrogeology. Generally, very few places such as the beam stops, target stations, injection and extraction sectors can have high enough radiation fields to produce radionuclides in the soil outside the enclosures. During the design, construction, or an upgrade in the intensity of existing beams, measures are taken to minimize the production of activated soil. The only leachable radionuclides known to be produced in the Fermilab soil are {sup 3}H, {sup 7}Be , {sup 22}Na, {sup 45}Ca and {sup 54}Mn and it has been determined that only {sup 3}H, and {sup 22}Na, because of their longer half lives and greater leachabilities, may significantly impact ground water resources.In themore » past, Fermilab has developed and used the Single Resident Well Model (SRWM) to estimate the ground water activation. Recently, the Concentration Model (CM), a more realistic method which depends on the site hydrogeology has been developed to decide the shielding requirements of the high radiation sites, and to calculate the ground water activation and its subsequent migration to the aquifer. In this report, the concentration of radionuclide released to the surface waters and the aquifer around the MI40 beam absorber are calculated. Subsequently, the ultimate limit on the primary proton beam intensity to be aborted on the Main Injector beam absorber is determined.« less
124689502
A POSSIBLE SPECTROMETER FOR ACCOMPLISHING A SECONDARY BEAM SURVEY AT NAL.
123487894
The small angle tile calorimeter in the DELPHI experiment
Abstract The Small angle TIle Calorimeter (STIC) provides calorimetric coverage in the very forward region of the DELPHI experiment at the CERN LEP collider. The structure of the calorimeters, built with a so-called “shashlik” technique, gives a perfectly hermetic calorimeter and still allows for the insertion of tracking detectors within the sampling structure to measure the direction of the showering particle. A charged-particle veto system, composed of two scintillator layers, makes it possible to trigger on single photon events and provides e–γ separation. Results are presented from the extensive studies of these detectors in the CERN testbeams prior of installation and of the detector performance at LEP.
117135799
Physics with the MAC detector
New results, obtained during the previous year at the PEP colliding beam rings with the MAC detector at a center of mass energy of 29 GeV, are presented.
109609645
Chelonia : A self-healing, replicated storage system
Chelonia is a novel grid storage system designed to fill the requirements gap between those of large, sophisticated scientific collaborations which have adopted the grid paradigm for their distributed storage needs, and of corporate business communities gravitating towards the cloud paradigm. Chelonia is an integrated system of heterogeneous, geographically dispersed storage sites which is easily and dynamically expandable and optimized for high availability and scalability. The architecture and implementation in term of web-services running inside the Advanced Resource Connector Hosting Environment Dameon (ARC HED) are described and results of tests in both local -area and wide-area networks that demonstrate the fault tolerance, stability and scalability of Chelonia will be presented. In addition, example setups for production deployments for small and medium-sized VO's are described.
128147551
Searches for the SM Higgs boson at LEP with s**(1//2) <= 189-GeV
12181544
PROTOTYPE TESTS FOR A VERTEX CHAMBER
We describe the design parameters for a pressurized drift chamber under construction for use with the MAC detector at PEP to operate within 3 cm of the beam line. The chamber is constructed of 7 mm diameter tubes of aluminized mylar with wall thickness of 0.10 mm. The tracking device incorporating these tubes is particularly simple to construct and can be configured so that any malfunctioning tube cau be remotely disconnected without affecting overall og erations. Resolution studies made in a SLAC test beam with a prototype over a wide range of gases and operating conditions are reported. The resolutions obtained were in the 10-40 micron range. It was found that the chamber could be operated satisfactorily, using heavily quenched gases, at high pressures (~4 atm) and operating voltages of ~4 kV in a mode for which saturated streamers were initiated with high efficiency by single electrons. Single electron gains for this mode were -108. The streamers were confined to a region of the wire with dimension of the order of a few hundred microns and count rates in excess of lo4 Hz/cm could be sustained with low dead-times. Further studies are in progress on chamber lifetimes with a variety of gas Elliogs. For our specific application this is of particular importance as the vertex chamber is expected to run in regions of high radiation backgrounds. As was expected for a chamber with extended cathodes, lifetimes were good. Actual lifetimes observed to date with our tube configurations have ranged from 0.05 coul/cm integrated current on the anode for 50:50 argon-isobutane to ~1 coul/cm for a mix of 49% A: 50% CO2: 1% C&. The results of these tests show our design goals to be achievable. Additionally they provide a basis on which to design high precision tracking devices particularly in applications where the device is to be operated in regions of difficult physical access or high ambient radiation levels.