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Optics of High-Energy Beams

Description: Many of the experiments now being conducted on high-energy accelerators requires the use of beams of charged secondary particles. It is worth while at this time to attempt to summarize information about some of the most useful methods of setting up such beams. We are not concerned here with the primary beam of the accelerator. Rather, they assume that a target is struck by the primary beam and that it is desired to form a beam from the secondary charged particles that emerge from collisions within the target. The simplest system of forming this beam of secondary particles involves the use of magnetic fields only. In most cases it is desirable to obtain a beam of particles of known magnetic rigidity, or momentum. The bulk of this article is addressed to this problem. Some comments are also made about the use of electric fields in conjunction with magnetic fields. The inclusion of electric fields allows the separation of a beam of known momentum into its various components according to the velocities of the particles, hence according to the masses of the particles. These are referred to as ''separated beams''.
Date: May 1, 1960
Creator: Chamberlain, Owen
Partner: UNT Libraries Government Documents Department

Search for Ultra High-Energy Neutrinos with AMANDA-II

Description: A search for diffuse neutrinos with energies in excess of 10{sup 5} GeV is conducted with AMANDA-II data recorded between 2000 and 2002. Above 10{sup 7} GeV, the Earth is essentially opaque to neutrinos. This fact, combined with the limited overburden of the AMANDA-II detector (roughly 1.5 km), concentrates these ultra high-energy neutrinos at the horizon. The primary background for this analysis is bundles of downgoing, high-energy muons from the interaction of cosmic rays in the atmosphere. No statistically significant excess above the expected background is seen in the data, and an upper limit is set on the diffuse all-flavor neutrino flux of E{sup 2} {Phi}{sub 90%CL} < 2.7 x 10{sup -7} GeV cm{sup -2}s{sup -1} sr{sup -1} valid over the energy range of 2 x 10{sup 5} GeV to 10{sup 9} GeV. A number of models which predict neutrino fluxes from active galactic nuclei are excluded at the 90% confidence level.
Date: November 19, 2007
Creator: Collaboration, IceCube; Klein, Spencer & Ackermann, M.
Partner: UNT Libraries Government Documents Department

Tables of Two U$sup 235$ Fission Spectra

Description: The U/sup 235/ fission spectrum is tabulated as a function of energy for two analytic representations. The table contains the distribution functions, their first derivatives, and their first integrals up to 10 Mev. (auth)
Date: October 1, 1957
Creator: Howerton, R. J.; Bengston, J. & French, S. J.
Partner: UNT Libraries Government Documents Department

2 MW upgrade of the Fermilab Main Injector

Description: In January 2002, the Fermilab Director initiated a design study for a high average power, modest energy proton facility. An intensity upgrade to Fermilab's 120-GeV Main Injector (MI) represents an attractive concept for such a facility, which would leverage existing beam lines and experimental areas and would greatly enhance physics opportunities at Fermilab and in the U.S. With a Proton Driver replacing the present Booster, the beam intensity of the MI is expected to be increased by a factor of five. Accompanied by a shorter cycle, the beam power would reach 2 MW. This would make the MI a more powerful machine than the SNS or the J-PARC. Moreover, the high beam energy (120 GeV) and tunable energy range (8-120 GeV) would make it a unique high power proton facility. The upgrade study has been completed and published. This paper gives a summary report.
Date: June 4, 2003
Creator: Chou, Weiren
Partner: UNT Libraries Government Documents Department

POLIDENT: A Module for Generating Continuous-Energy Cross Sections from ENDF Resonance Data

Description: POLIDENT (POint LIbraries of Data from ENDF/B Tapes) is an AMPX module that accesses the resonance parameters from File 2 of an ENDF/B library and constructs the continuous-energy cross sections in the resonance energy region. The cross sections in the resonance range are subsequently combined with the File 3 background data to construct the cross-section representation over the complete energy range. POLIDENT has the capability to process all resonance reactions that are identified in File 2 of the ENDF/B library. In addition, the code has the capability to process the single- and multi-level Breit-Wigner, Reich-Moore and Adler-Adler resonance formalisms that are identified in File 2. POLIDENT uses a robust energy-mesh-generation scheme that determines the minimum, maximum and points of inflection in the cross-section function in the resolved-resonance region. Furthermore, POLIDENT processes all continuous-energy cross-section reactions that are identified in File 3 of the ENDF/B library and outputs all reactions in an ENDF/B TAB1 format that can be accessed by other AMPX modules.
Date: October 20, 2000
Creator: Dunn, M.E.
Partner: UNT Libraries Government Documents Department


Description: The operating principle of the tandem Van de Graaff accelerator is discussed. The use and operation of the 4.5Mev Van de Graaff generator are described. An upper limit was set for the observed mean life of the first excited atate of Ca/sup 43/ and a lower limit was set for the partial mean life for decay by E2 transition from the same state. Groups of delayed neutrons from N/sup 17/ precursors were observed at energies of 1.225 and 0.425 Mev, corresponding to BETA decay to 3/2- atates in Oil in agreement with the shell model. An investigation is reported of the fragmentation of benzene and ethylene with high-energy electrons. The plasma research program is described. The major research described is an experimental study of basic propenties of plasmas produced in homogeneous high-frequency electric fields at low pressure. The doublet splittings in He/sup 5/, N/sup 15/, and Oil (closed shells plus or minus one nucleon) are adequately explained in terms of the combination of the second- order effect due to the tensor force and the firat-order effect due to the L-S potential. (For preceding pericd see ANL-6235.) (W.L.H.)
Date: October 31, 1961
Partner: UNT Libraries Government Documents Department

Global Infrasonic Monitoring of Large Bolides.

Description: Using recent infrasonic data (1995-2001) and older infrasonic data recorded by AFTAC (1960-1974), we have refined our estimates of the global influx rate (cumulative influx) of large bolides with sufficient strength to deeply penetrate the atmosphere (below {approx} 50 km). The number of bolides arriving as a function of their initial source energy has been estimated from a least-squares curve-fit of our database of 19 bolides (for a source energy > 0.053 kt) with the resulting values and an estimate of the associated statistical counting errors: 30.3{+-} 6 bolides at {ge}0.1 kt, 5.8{+-} 2 at {ge}1 kt and 0.84{+-} 0.25 at {ge}15 kt. In this work we also used these estimates to infer the recurrence interval for energy levels slightly outside the original source energy range, The Tunguska bolide of 1908 ({approx}10 Mt) is a prime example of a previously observed body of great interest. Almost regardless of how we analyze the recent data, the conclusion is that bolides with Tunguska type energy levels should reoccur on the average every 120{+-}10 years.
Date: January 1, 2001
Creator: ReVelle, D. O. (Douglas O.)
Partner: UNT Libraries Government Documents Department


Description: In specifying the magnets for an accelerator, one must be able to determine the aperture required by the beam. In some machines, in particular FFAGs, there is a significant variation in the closed orbit and beta functions over the energy range of the machine. In addition, the closed orbit and beta functions may vary with the longitudinal position in the magnet. It is necessary to determine a magnet aperture which encloses the beam ellipses at all energies and all positions in the magnet. This paper describes a method of determining the smallest circular aperture enclosing an arbitrary number of midplane-centered ellipses.
Date: September 14, 2004
Creator: BERG,S. J.
Partner: UNT Libraries Government Documents Department

What can we expect from future accelerators

Description: This talk covers a general but highly subjective overview of the expectation for new accelerator development. An updated version of the Livingston chart demonstrates the exponential growth in time of the equivalent laboratory energy of accelerators. A similar Livingston chart pertaining only to electron-positron colliders shows an exponential growth but in the past only one technology - electron-positron storage rings - have been responsible for this development. The question addressed is whether the type of exponential growth reflected by these two charts can be sustained in the future.
Date: June 1, 1984
Creator: Panofsky, W.K.H.
Partner: UNT Libraries Government Documents Department


Description: We present new results of searches for neutrino point sources in the northern sky, using data recorded in 2007-08 with 22 strings of the IceCube detector (approximately one-fourth of the planned total) and 275.7 days of livetime. The final sample of 5114 neutrino candidate events agrees well with the expected background of atmospheric muon neutrinos and a small component of atmospheric muons. No evidence of a point source is found, with the most significant excess of events in the sky at 2.2 {sigma} after accounting for all trials. The average upper limit over the northern sky for point sources of muon-neutrinos with E{sup -2} spectrum is E{sup 2} {Phi}{sub {nu}{sub {mu}}} < 1.4 x 10{sup -1} TeV cm{sup -2}s{sup -1}, in the energy range from 3 TeV to 3 PeV, improving the previous best average upper limit by the AMANDA-II detector by a factor of two.
Date: May 14, 2009
Creator: Collaboration, IceCube & Klein, Spencer
Partner: UNT Libraries Government Documents Department

Multi-year search for a diffuse flxu of muon neutrinos with AMANDA-II

Description: A search for TeV-PeV muon neutrinos from unresolved sources was performed on AMANDA-II data collected between 2000 and 2003 with an equivalent livetime of 807 days. This diffuse analysis sought to find an extraterrestrial neutrino flux from sources with non-thermal components. The signal is expected to have a harder spectrum than the atmospheric muon and neutrino backgrounds. Since no excess of events was seen in the data over the expected background, an upper limit of E{sup 2}{Phi}{sub 90%C.L.} < 7.4 x 10{sup -8} GeV cm{sup -2} s{sup -1} sr{sup -1} is placed on the diffuse flux of muon neutrinos with a {Phi} {proportional_to} E{sup -2} spectrum in the energy range 16 TeV to 2.5 PeV. This is currently the most sensitive {Phi} {proportional_to} E{sup -2} diffuse astrophysical neutrino limit. We also set upper limits for astrophysical and prompt neutrino models, all of which have spectra different than {Phi} {proportional_to} E{sup -2}.
Date: April 13, 2008
Creator: Collaboration, IceCube; Klein, Spencer; Achterberg, A. & Collaboration, IceCube
Partner: UNT Libraries Government Documents Department

Search for high-energy muon neutrinos from the"naked-eye" GRB080319B with the IceCube neutrino telescope

Description: We report on a search with the IceCube detector for high-energy muon neutrinos from GRB080319B, one of the brightest gamma-ray bursts (GRBs) ever observed. The fireball model predicts that a mean of 0.12 events should be detected by IceCube for a bulk Lorentz boost of the jet of 300. In both the direct on-time window of 66 s and an extended window of about 300 s around the GRB, there was no excess found above the background. The 90% C.L. upper limit on the number of track-like events from the GRB is 2.7, corresponding to a muon neutrino fluence limit of 9.0 x 10{sup -3} erg cm{sup -2} in the energy range between 145 TeV and 2.1 PeV, which contains 90% of the expected events.
Date: February 1, 2009
Creator: Collaboration, IceCube & Abbasi, R.
Partner: UNT Libraries Government Documents Department

Search for Point Sources of High Energy Neutrinos with Final Data from AMANDA-II

Description: We present a search for point sources of high energy neutrinos using 3.8 years of data recorded by AMANDA-II during 2000-2006. After reconstructing muon tracks and applying selection criteria designed to optimally retain neutrino-induced events originating in the Northern Sky, we arrive at a sample of 6595 candidate events, predominantly from atmospheric neutrinos with primary energy 100 GeV to 8 TeV. Our search of this sample reveals no indications of a neutrino point source. We place the most stringent limits to date on E{sup -2} neutrino fluxes from points in the Northern Sky, with an average upper limit of E{sup 2}{Phi}{sub {nu}{sub {mu}}+{nu}{sub {tau}}} {le} 5.2 x 10{sup -11} TeV cm{sup -2} s{sup -1} on the sum of {nu}{sub {mu}} and {nu}{sub {tau}} fluxes, assumed equal, over the energy range from 1.9 TeV to 2.5 PeV.
Date: March 6, 2009
Creator: Collaboration, IceCube & Klein, Spencer
Partner: UNT Libraries Government Documents Department


Description: The main purpose of Chemistry Division personnel in using the Bevatron will be to learn as much as possible about nuclear reactions in the Bev energy range using the radiochemical approach. The type and extent of these experiments will depend greatly on the beam intensity. Significant results can be obtained at 10{sup 6} or 10{sup 7} protons per pulse, but it is highly desirable that this figure ultimately be raised to 10{sup 10} or greater.
Date: March 29, 1954
Creator: Hyde, Earl K.
Partner: UNT Libraries Government Documents Department

Observation of high energy atmospheric neutrinos with antarctic muon and neutrino detector array

Description: The Antarctic Muon and Neutrino Detector Array (AMANDA) began collecting data with ten strings in 1997. Results from the first year of operation are presented. Neutrinos coming through the Earth from the Northern Hemisphere are identified by secondary muons moving upward through the array. Cosmic rays in the atmosphere generate a background of downward moving muons, which are about 10{sup 6} times more abundant than the upward moving muons. Over 130 days of exposure, we observed a total of about 300 neutrino events. In the same period, a background of 1.05 x 10{sup 9} cosmic ray muon events was recorded. The observed neutrino flux is consistent with atmospheric neutrino predictions. Monte Carlo simulations indicate that 90 percent of these events lie in the energy range 66 GeV to 3.4 TeV. The observation of atmospheric neutrinos consistent with expectations establishes AMANDA-B10 as a working neutrino telescope.
Date: May 7, 2002
Creator: Ahrens, J.; Andres, E.; Bai, X.; Barouch, G.; Barwick, S.W.; Bay, R.C. et al.
Partner: UNT Libraries Government Documents Department