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Measurements of charged two-particle exclusive states in photon-photon interactions

Description: A description is given of an experiment performed at the PEP electron-positron storage ring, using the DELCO detector, to measure the formation of charged particle pairs from interactions of pairs of virtual photons radiated from the colliding electron beams. The final states which are measured are electron-positron pairs, charged pion pairs, charged kaon pairs, and proton pairs. Electron-positron pairs are separated from other data by use of gas Cerenkov counters. The shapes of all kinematic distributions are found to agree with predictions of quantum electrodynamics. These data also are used as an accurate normalization for subtraction of the muon-pair background and for measurement of the cross sections of the three hadronic channels. Pion pairs are measured in the mass range from 0.6 to 2.0 GeV, where production of the f (1270) resonance is observed to interfere with significant continuum production. The continuum is well described by single-pion exchange, allowing a measurement of the f two-photon partial width of 3.47 +- 0.37 keV. No a priori assumption is made about the ratio of helicity amplitudes, and the phenomenological model used in fitting the data is constrained to satisfy elastic unitarity. If unitarity is not required, then the fitted partial width is a factor of 0.83 lower than the quoted value. The Q/sup 2/ dependence of the cross section is found to be consistent with predictions of the Generalized Vector Dominance Model. Kaon pairs and proton pairs are identified by time-of-flight measurements. Kaon pairs are measured in the mass range from 1.3 to 2.0 GeV, where production of the f' (1520) resonance is observed. The ratio of the f and f' two-photon partial widths is found to be consistent with SU(3) quark model predictions with a mixing angle of 28 +- 4 degrees. Twenty-three proton pairs are observed.
Date: March 1, 1986
Creator: Johnson, R.P.
Partner: UNT Libraries Government Documents Department

Stochastic stacking without filters

Description: The rate of accumulation of antiprotons is a critical factor in the design of p anti p colliders. A design of a system to accumulate higher anti p fluxes is presented here which is an alternative to the schemes used at the CERN AA and in the Fermilab Tevatron I design. Contrary to these stacking schemes, which use a system of notch filters to protect the dense core of antiprotons from the high power of the stack tail stochastic cooling, an eddy current shutter is used to protect the core in the region of the stack tail cooling kicker. Without filters one can have larger cooling bandwidths, better mixing for stochastic cooling, and easier operational criteria for the power amplifiers. In the case considered here a flux of 1.4 x 10/sup 8/ per sec is achieved with a 4 to 8 GHz bandwidth.
Date: December 1, 1982
Creator: Johnson, R.P. & Marriner, J.
Partner: UNT Libraries Government Documents Department

Pbar Source Group summary

Description: Maxium antiproton accumulation rates have been investigated. A scheme is outlined which would accumulate more than 7E8 pbars/s ina form suitable for a peak luminosity of more than 0.5E33 /(s*cm**2) in a single SSC ring. This scheme utilizes only moderate extrapolations of present technology. Each of the stages in the accumulation process has been investigated in some detail with the same calculational tools as have been used in the CERN and Fermilab pbar sources. The results of these calculations and possibilities for improvements are discussed.
Date: January 1, 1984
Creator: Johnson, R.P. & Simpson, J.
Partner: UNT Libraries Government Documents Department

LMFBR safety: Interim test report for the characterization of released particle tests conducted at INEL during FY 1979. [Deposition from sodium plume]

Description: Two additional atmospheric sodium release tests were jointly conducted by ESG and ARL at INEL. These tests were conducted under very stable (Pasquill E and G) meteorological conditions where the natural humidity content was high (47 and 96% RH). Sufficient experimental data was obtained on Test 7 to quantitatively qualify the formation of Na/sub 2/CO/sub 3/ in the open atmosphere from primary sodium combustion products. These data show that a maximum concentration of approx. 60% Na/sub 2/CO/sub 3/ is reached with the plume 100 meters from the release point. This concentration increases slightly as the plume is dispersed beyond 2400 meters. The available particle fallout data is consistent with predictions.
Date: February 8, 1979
Creator: Johnson, R.P. & Nelson, C.T.
Partner: UNT Libraries Government Documents Department

Interim Storage Facility decommissioning. Final report

Description: Decontamination and decommissioning of the Interim Storage Facility were completed. Activities included performing a detailed radiation survey of the facility, removing surface and imbedded contamination, excavating and removing the fuel storage cells, restoring the site to natural conditions, and shipping waste to Hanford, Washington, for burial. The project was accomplished on schedule and 30% under budget with no measurable exposure to decommissioning personnel.
Date: March 15, 1985
Creator: Johnson, R.P. & Speed, D.L.
Partner: UNT Libraries Government Documents Department

Aerospace Safety Program: summary report

Description: Projects in support of the Aerospace Nuclear Safety Program are summarized. The objective of the program was to evaluate the radiological safety of SNAP systems and to develop methods and designs to assure that safety. Projects summarized are analyses and experiments for determining: (1) the disintegration of reactors reentering the atmosphere; (2) the burnup of fuel elements reentering the atmosphere, including ablation and dispersal of particles; (3) reactor criticality conditions and the assurance of subcriticality in water; (4) the behavior of reactors in transient power operation; (5) the nuclear behavior of reactors on impact with the earth and in handling accidents; (6) the assurance of shutdown at the end of the power production lifetime; (7) risks by various exposure modes from different methods of reactor disposal; and (8) thermophysical properties of SNAP fuel materials. (auth)
Date: July 30, 1973
Creator: Otter, J. M.; Buttrey, K. E. & Johnson, R. P.
Partner: UNT Libraries Government Documents Department

Control and initial operation of the Fermilab BO low. beta. insertion

Description: The operation of the Fermilab BO low ..beta.. insertion involves the coordinated control of the 4 strings of quadrupoles of the insertion itself along with several magnetic correction elements (20 dipoles for the closed orbit, 2 quad circuits for betatron tunes, 1 skew quad circuit for coupling, and 2 sextupole circuits for chromaticity). When the beam is stored at high energy, these elements must correct the errors induced by the strong superconducting quadrupoles of the insertion as the optics are smoothly changed from the fixed target configuration to the low ..beta.. state. The techniques and control programs for these manipulations and initial tests using a single coasting beam are described. 6 refs., 4 figs.
Date: June 1, 1985
Creator: Finley, D.A.; Johnson, R.P. & Willeke, F.
Partner: UNT Libraries Government Documents Department

Fermilab timeline generation system

Description: In this paper the technique used to control the relative timing and synchronization of the major accelerator systems at Fermilab is described. The various operating modes of the injector accelerators include fixed target and colliding beam operation in conjunction with simultaneous machine studies. For example, in a 60 second interval the conventional main Ring may be called upon to: (a) load the Tevatron with 12 high intensity Booster batches each containing 82 rf bunches at 150 GeV, (b) transfer a Booster batch at 8 GeV with 8 rf bunches to the Debuncher or Accumulator, (c) accelerate high intensity beam several times to 120 GeV for antiproton production, and (d) accelerate beam to 150 GeV for Main Ring studies. In the case of colliding beam operation, the different tasks can be even more varied. All this requires a simple, flexible means of coordination.
Date: June 1, 1985
Creator: Johnson, R.P.; Knopf, W.R. & Thomas, A.D.
Partner: UNT Libraries Government Documents Department

U. S. position paper on sodium fires, design and testing

Description: Sodium combustion phenomena and U.S. computer codes developed for sodium fires are discussed. Ways of preventing and mitigating sodium fires are described. Effects of sodium fires and spills on LMFBR structural materials, thermal insulation materials, and equipment/instrumentation are considered. (DLC)
Date: May 1, 1982
Creator: Hilliard, R.K.; Johnson, R.P. & Powers, D.A.
Partner: UNT Libraries Government Documents Department

A new Tevatron Collider working point near the integer

Description: It is well established that in hadron colliders the beam-beam interaction is more harmful in the presence of machine resonances of the form m{nu}{sub x} + n{nu}{sub y} = p, where {vert bar}m{vert bar} + {vert bar}n{vert bar} is the order of the resonance. Since the closest a resonance line can be to the integer stopband is 1/order, the closer the working point is to the integer, the fewer lower order resonances there are to enhance the beam-beam effects. A shift of the working point of the Tevatron from 19.4 to values near 19 and 20 has been studied. Problems with closed orbit control, dispersion matching, and matched low {beta} insertions were considered. An excellent solution for the B0 insertion was found which has an improved {beta}*. A new injection optics allows a transition to the low {beta} optics which is much easier than the one now used. Results from the first machine studies demonstrate the ability to control the orbit with tunes of 19.03 horizontal and 20.03 vertical. Further studies require the activation of additional quadrupole compensation circuits. 4 refs. , 2 figs.
Date: December 1, 1989
Creator: Johnson, R.P. & Zhang, P.
Partner: UNT Libraries Government Documents Department

Common mode noise on the main Tevatron bus and associated beam emittance growth

Description: Overlap of betatron tune frequencies with the power supply noise spectrum can cause transverse beam emittance growth in a storage ring. We have studied this effect for tunes near the integer, where the betatron frequency is low. By injecting noise onto the main power supply bus, it was determined that common mode noise was the dominant source of emittance growth. A noise suppression feed-back loop was then used to reduce the noise and the emittance growth. These experiments are described as are investigations of the common mode propagation along the Tevatron bus and measurements of the fields generated by common mode excitation of isolated Tevatron magnets. 3 refs., 4 figs.
Date: May 1, 1991
Creator: Zhang, P.; Johnson, R.P.; Kuchnir, M.; Siergiej, D. & Wolff, D.
Partner: UNT Libraries Government Documents Department

LMFBR safety: Task 10 - characterization of sodium fires and fission product

Description: The objectives of this project are to: develop a computer program for calculating two-dimensional, transient, natural convection phenomena such as those arising from various sodium spill accidents in Liquid Metal Fast Breeder Reactor (LMFBR) heat transfer equipment vaults, head compartments, containment buildings, and secondary heat transfer systems; develop experimental programs and conduct tests that will characterize the behavior of sodium, sodium oxide, fuel, fission product, and other aerosols as they might be generated by various postulated LMFBR accidents; determine by analysis and experiment the generation and transport of these aerosols; and determine the effects of an accident in an LMFBR involving fuel melting by contacting molten UO/sub 2/ (a fuel simulant) with stainless steel, sodium, concrete, and various sacrificial materials.
Date: January 1, 1977
Creator: Heisler, M.P.; Johnson, R.P.; Nelson, C.T.; Vaughan, E.U.; Guderjahn, C. & Eytel, L.
Partner: UNT Libraries Government Documents Department

LMFBR safety program. Quarterly technical progress report, October-December 1976

Description: Information related to sodium fires and fission products in LMFBR type reactors is presented concerning SOMIX code development; sodium jet dispersal tests; aerosol leakage; high temperature-concentration aerosol tests; aerosol source term size; and properties of high temperature fuel mixtures.
Date: February 25, 1977
Creator: Heisler, M.P.; Johnson, R.P.; Nelson, C.T.; Vaughan, E.U.; Guderjahn, C. & Eytel, L.
Partner: UNT Libraries Government Documents Department

Characterization of sodium fires and fission products. Task 10

Description: Objectives of this project are to: (1) Develop a computer program for calculating two-dimensional, transient, natural convection phenomena such as those arising from various sodium spill accidents in Liquid Metal Fast Breeder Reactor (LMFBR) heat transfer equipment vaults, head compartments, containment buildings, and secondary heat transfer systems. (2) Develop experimental programs and conduct tests that will characterize the behavior of sodium, sodium oxide, fuel, fission product, and other aerosols as they might be generated by various postulated LMFBR accidents. (3) Determine by analysis and experiment the generation and transport of these aerosols with respect to source (location, type, and configuration), release dispersal, agglomeration attentuation, and removal for the entire course of events associated with real and hypothetical accident conditions. (4) Determine the effects of an accident in an LMFBR involving fuel melting by contacting molten UO/sub 2/ (a fuel simulant) with stainless steel, sodium, concrete, and various sacrificial materials.
Date: January 1, 1977
Creator: Heisler, M.P.; Johnson, R.P.; Nelson, C.T.; Vaughan, E.U. & Guderjahn, C.
Partner: UNT Libraries Government Documents Department

Phase and Frequency Locked Magnetrons for SRF Sources

Description: Magnetrons are low-cost highly-efficient microwave sources, but they have several limitations, primarily centered about the phase and frequency stability of their output. When the stability requirements are low, such as for medical accelerators or kitchen ovens, magnetrons are the very efficient power source of choice. But for high energy accelerators, because of the need for frequency and phase stability - proton accelerators need 1-2 degrees source phase stability, and electron accelerators need .1-.2 degrees of phase stability - they have rarely been used. We describe a novel variable frequency cavity technique which will be utilized to phase and frequency lock magnetrons.
Date: May 1, 2009
Creator: Neubauer, M.; Johnson, R.P.; /Muons Inc., Batavia; Popovic, M.; Moretti, A. & /Fermilab
Partner: UNT Libraries Government Documents Department

Studies of a gas-filled helical muon beam cooling channel

Description: A helical cooling channel (HCC) can quickly reduce the six dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of solenoidal, helical dipole, and helical quadrupole magnetic fields to provide the focusing and dispersion needed for emittance exchange as the beam follows an equilibrium helical orbit through a continuous homogeneous absorber. The beam dynamics of a gas-filled helical muon beam cooling channel is studied by using Monte Carlo simulations. The results verify the cooling theory [1] of the helical magnet. The cooling performance has been improved by correcting chromatic aberration and the non-linear effects caused by the ionization energy loss process. With these improvements, a simulated cooling channel of 160 meters length has achieved a reduction of 6-dimensional (6D) phase space by a factor of 50,000.
Date: June 1, 2006
Creator: Yonehara, K.; /Fermilab; Derbenev, Y.; Lab, /Jefferson; Johnson, R.P.; Roberts, T.J. et al.
Partner: UNT Libraries Government Documents Department