118107314
Tunneling beyond the Fermilab site
An accelerator that crosses the Fermilab site boundary must have a minimum effect on the surrounding environment and the people residing in the area. Unobstructed public access should be allowed above the ring except in relatively few areas such as the injection, dump, and experimental regions. The accelerator should be a benign and unobtrusive neighbor not only when it is completed but also in the construction period. For these reasons underground tunneling for all or most of the ring seems attractive. In this note we look into some questions raised by tunneling beyond the Fermilab site. Most of our discussion is of general applicability. However, we will use as examples two specific ring configurations. The examples have not been optimized from the point of view of physics output or accelerator technology but are just specific examples which allow us to study questions of tunneling. One is a ring of 5 km radius (5 TeV) tangent to the Tevatron and entirely east of the Fox River and fed by a beam from the Tevatron which crosses under the river. We assume that each of these machines will have 100 beam fills per year and we scale the maximum intensities with themore » accelerator radii. Thus we assume that there will be 1.0 E14 protons in each beam of the 20 TeV machine and 2.5 E13 for the 5 TeV machine.« less
118121131
USE OF THE 3.5-MRAD BEAM FOR ELECTRONS.
123662576
Observation of a likely example of the decay of a charmed particle produced in a high energy neutrino interaction
Abstract In a study of neutrino interactions occurring in nuclear emulsion, an event has been found that is most readily interpreted as the decay of a charmed particle with lifetime a few times 10 −13 s.
120981188
LARGE-ANGLE PION--PROTON ELASTIC SCATTERING AT HIGH ENERGIES.
124689502
A POSSIBLE SPECTROMETER FOR ACCOMPLISHING A SECONDARY BEAM SURVEY AT NAL.
124267104
DISCUSSION OF POSSIBLE USES OF RF BEAM STRUCTURE IN COUNTER EXPERIMENTS AT NAL.
110552488
Complete distributed computing environment for a HEP experiment: experience with ARC-connected infrastructure for ATLAS
Computing and storage resources connected by the Nordugrid ARC middleware in the Nordic countries, Switzerland and Slovenia are a part of the ATLAS computing Grid. This infrastructure is being commissioned with the ongoing ATLAS Monte Carlo simulation production in preparation for the commencement of data taking in 2008. The unique non-intrusive architecture of ARC, its straightforward interplay with the ATLAS Production System via the Dulcinea executor, and its performance during the commissioning exercise is described. ARC support for flexible and powerful end-user analysis within the GANGA distributed analysis framework is also shown. Whereas the storage solution for this Grid was earlier based on a large, distributed collection of GridFTP-servers, the ATLAS computing design includes a structured SRM-based system with a limited number of storage endpoints. The characteristics, integration and performance of the old and new storage solutions are presented. Although the hardware resources in this Grid are quite modest, it has provided more than double the agreed contribution to the ATLAS production with an efficiency above 95% during long periods of stable operation.
122512473
Linear interpolation of histograms
A prescription is defined for the interpolation of probability distributions that are assumed to have a linear dependence on a parameter of the distributions. The distributions may be in the form of continuous functions or histograms. The prescription is based on the weighted mean of the inverses of the cumulative distributions between which the interpolation is made. The result is particularly elegant for a certain class of distributions, including the normal and exponential distributions, and is useful for the interpolation of Monte Carlo simulation results which are time-consuming to obtain. ( 1999 Elsevier Science B.V. All rights reserved.
119294334
A comment on estimating sensitivity to neutrino mass hierarchy in neutrino experiments
Recently it has been proposed, in the context of experiments designed to resolve the neutrino mass hierarchy, to use the average posterior probability of one of the hypotheses as a measure of sensitivity of future experiments. This has led to sensitivity estimates that are drastically lower than common conventions. We point to the fact that such estimates can be severely misleading: the probability that an experiment would actually produce a result similar to the average value can be in fact negligibly small. We emphasize again the simple relation between median significance and the likelihood ratio evaluated with the ``Asimov'' data set, which can be used to express experimental sensitivity in Bayesian terms as well.
119941628
Prospects for the Standard Model Higgs Boson Search in the LEP 2000 Run
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.