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Radiation shielding for the Main Injector collimation system

Description: The results of Monte Carlo radiation shielding studies performed with the MARS15 code for the Main Injector collimation system are presented and discussed. A Proton Plan was developed recently at Fermilab for the benefit of the existing neutrino programs as well as to increase anti-proton production for the Tevatron programs [1]. As a part of the plan, the intensity of proton beams in the Main Injector (MI) should be increased by means of slip-stacking injection. In order to localize beam loss associated with the injection, a collimation system was designed [2] that satisfies all the radiation and engineering constraints. The system itself comprises a primary collimator and four secondary ones to which various masks are added. It is assumed that beam loss at the slip-stacking injection is equal to 5% of total intensity which is 5.5 x 10{sup 13} protons per pulse [2]. As far as pulse separation is 2.2 seconds, one has (5.5 x 10{sup 13}/2.2) x 0.05 = 1.25 x 10{sup 12} protons interacting per second with the primary collimator. In the paper the geometry model of the corresponding MI region and beam loss model are described. The model of the region was built by means of the MAD-MARS Beam Line Builder (MMBLB) [3] using results of the collimation studies [2]. The results of radiation shielding calculations performed with the MARS15 code [4] are presented.
Date: December 1, 2007
Creator: Rakhno, Igor
Partner: UNT Libraries Government Documents Department

Diagnostic beam absorber in Mu2e beam line

Description: Star density, hadron flux, and residual dose distributions are calculated around the {mu}2e diagnostic beam absorber. Corresponding surface and ground water activation, and air activation are presented as well.
Date: March 1, 2011
Creator: Rakhno, Igor
Partner: UNT Libraries Government Documents Department

beam loss scenarios for MuCool Test Area

Description: The MuCool Test Area (MTA) is an intense primary beam facility derived directly from the Fermilab Linac to test heat deposition and other technical concerns associated with the liquid hydrogen targets, gas-filled RF cavities, and other apparatus being developed to cool intense, large-emittance muon beams. In this study the results of Monte Carlo modeling of several beam loss scenarios are presented. The MTA facility was designed to test targets and other muon cooling apparatus using the intense Fermilab Linac beam. The requested intensity of the proton beam for the MTA is essentially full Linac capability, or 1.6 x 10{sup 13} protons per pulse and an energy of 400 MeV. Two modes of operation will be supported in the MuCOOL beamline: one mode for emittance measurements (and beamline studies) and a second mode for MTA experiments. Maximum beam intensity for these two modes is: 9.6 x 10{sup 15} protons/hr - 600 beam pulses/hour of full Linac beam pulse intensity (1.6 x 10{sup 13} protons/pulse) to the emittance beam absorber and 9.6 x 10{sup 14} protons/hour - 60 beam pulses/hour of full Linac beam pulse intensity to experiments in the MTA experimental hall. This extremely high intensity implies careful investigation into and application of proper shielding materials and configuration in order to satisfy the following two requirements: (i) to reduce the instantaneous dose rate outside of the experimental enclosure to prescribed levels appropriate for the area considered; (ii) to ensure the civil construction of the hall is capable of additional shielding and, further, that the weight of the shielding is commensurate with the loading specifications of the enclosure, notably the ceiling. A number of scenarios for beam loss at different locations were studied in order to determine the maximum beam intensity which is in compliance with the existing shielding. The modeling was ...
Date: August 1, 2010
Creator: Rakhno, Igor; Johnstone, Carol & /Fermilab
Partner: UNT Libraries Government Documents Department

Optimization Studies for Radiation Shielding of a Superconducting RF Cavity Test Facility

Description: Test facilities for high-gradient superconducting RF cavities must be shielded for particle radiation, which is generated by field emitted electrons in the cavities. A major challenge for the shielding design is associated with uncertainty in modeling the field emission. In this work, a semi-empirical method that allows us to predict the intensity of the generated field emission is described. Spatial, angular and energy distributions of the generated radiation are calculated with the FISHPACT code. The Monte Carlo code MARS15 is used for modeling the radiation transport in matter. The detailed distributions of the generated field emission are used for studies with 9-cell 1.3 GHz superconducting RF cavities in the Fermilab Vertical Cavity Test Facility. This approach allows us to minimize the amount of shielding inside cryostat which is an essential operational feature.
Date: July 9, 2010
Creator: Ginsburg, Camille M.; Rakhno, Igor & /Fermilab
Partner: UNT Libraries Government Documents Department

Radiation shielding for the Fermilab Vertical Cavity Test Facility

Description: The results of radiation shielding studies for the vertical test cryostat VTS1 at Fermilab performed with the codes FISHPACT and MARS15 are presented and discussed. The analysis is focused on operations with two RF cavities in the cryostat. The vertical cavity test facility (VCTF) for superconducting RF cavities in Industrial Building 1 at Fermilab has been in operation since 2007. The facility currently consists of a single vertical test cryostat VTS1. Radiation shielding for VTS1 was designed for operations with single 9-cell 1.3 GHz cavities, and the shielding calculations were performed using a simplified model of field emission as the radiation source. The operations are proposed to be extended in such a way that two RF cavities will be in VTS1 at a time, one above the other, with tests for each cavity performed sequentially. In such a case the radiation emitted during the tests from the lower cavity can, in part, bypass the initially designed shielding which can lead to a higher dose in the building. Space for additional shielding, either internal or external to VTS1, is limited. Therefore, a re-evaluation of the radiation shielding was performed. An essential part of the present analysis is in using realistic models for cavity geometry and spatial, angular and energy distributions of field-emitted electrons inside the cavities. The calculations were performed with the computer codes FISHPACT and MARS15.
Date: March 1, 2010
Creator: Ginsburg, Camille; Rakhno, Igor & /Fermilab
Partner: UNT Libraries Government Documents Department

Shielding Studies for Superconducting RF Cavities at Fermilab

Description: A semi-empirical method that allows us to predict intensity of generated field emission in superconducting RF cavities is described. Spatial, angular and energy distributions of the generated radiation are calculated with the FISHPACT code. The Monte Carlo code MARS15 is used for modeling the radiation transport in matter. A comparison with dose rate measurements performed in the Fermilab Vertical Test Facility for ILC-type cavities with accelerating gradients up to 35 MV/m is presented as well.
Date: July 20, 2010
Creator: Ginsburg, Camille; Rakhno, Igor & /Fermilab
Partner: UNT Libraries Government Documents Department

Radiation damage due to electromagnetic showers

Description: Radiation-induced damage due to atomic displacements is essential to correctly predict the behavior of materials in nuclear reactors and at charged-particle accelerators. Traditionally the damage due to hadrons was of major interest. The recent increased interest in high-energy lepton colliders gave rise to the problem of prediction of radiation damage due to electromagnetic showers in a wide energy range--from a few hundred keV and up to a few hundred GeV. The report describes results of an electron- and positron-induced displacement cross section evaluation. It is based on detailed lepton-nucleus cross sections, realistic nuclear form-factors and a modified Kinchin-Pease damage model. Numerical data on displacement cross sections for various target nuclei is presented.
Date: May 1, 2008
Creator: Rakhno, Igor; Mokhov, Nikolai; Striganov, Sergei & /Fermilab
Partner: UNT Libraries Government Documents Department

Simulation of nucleon elastic scattering in the MARS14 code system

Description: Correct modeling of nucleon elastic scattering is of special importance in many applications at high energy accelerators, such as deep penetration, beam loss and collimation studies. In present paper, the work performed to update the MARS elastic scattering model at E < 5 GeV is described. Modern evaluated nuclear data as well as fitting formulae are used in the new model. For protons as projectiles, Coulomb scattering and Coulomb-nuclear interference are taken into account in addition to nuclear elastic scattering. Comparisons with experimental angular distributions and calculations by means of other codes are presented.
Date: November 26, 2001
Creator: Rakhno, Igor L.; Mohkov, N.; Sukhovitski, E. & Chiba, S.
Partner: UNT Libraries Government Documents Department

Radiation shielding calculations for MuCool test area at Fermilab

Description: The MuCool Test Area (MTA) is an intense primary beam facility derived directly from the Fermilab Linac to test heat deposition and other technical concerns associated with the liquid hydrogen targets being developed for cooling intense muon beams. In this shielding study the results of Monte Carlo radiation shielding calculations performed using the MARS14 code for the MuCool Test Area and including the downstream portion of the target hall and berm around it, access pit, service building, and parking lot are presented and discussed within the context of the proposed MTA experimental configuration.
Date: May 26, 2004
Creator: Rakhno, Igor & Johnstone, Carol
Partner: UNT Libraries Government Documents Department

Fermilab Main Injector Collimation Systems: Design, Commissioning and Operation

Description: The Fermilab Main Injector is moving toward providing 400 kW of 120 GeV proton beams using slip stacking injection of eleven Booster batches. Loss of 5% of the beam at or near injection energy results in 1.5 kW of beam loss. A collimation system has been implemented to localize this loss with the design emphasis on beam not captured in the accelerating RF buckets. More than 95% of these losses are captured in the collimation region. We will report on the construction, commissioning and operation of this collimation system. Commissioning studies and loss measurement tools will be discussed. Residual radiation monitoring of the Main Injector machine components will be used to demonstrate the effectiveness of these efforts.
Date: May 1, 2009
Creator: Brown, Bruce; Adamson, Philip; Capista, David; Drozhdin, A.I.; Johnson, David E.; Kourbanis, Ioanis et al.
Partner: UNT Libraries Government Documents Department

Design and commissioning of Fermilab's vertical test stand for ILC SRF cavities.

Description: As part of its ILC program, Fermilab is developing a facility for vertical testing of SRF cavities. It operates at a nominal temperature of 2K, using a cryoplant that can supply LHe in excess of 20g/sec and provide bath pumping capacity of 125W at 2K. The below-grade cryostat consists of a vacuum vessel and LHe vessel, equipped with magnetic shielding to reduce the ambient magnetic field to <10mG. Internal fixed and external movable radiation shielding ensures that exposure to personnel is minimized. The facility features an integrated personnel safety system consisting of RF switches, interlocks, and area radiation monitors.
Date: June 1, 2007
Creator: Ozelis, Joseph P.; Carcagno, Ruben; Ginsburg, Camille M.; Huang, Yuenian; Norris, Barry; Peterson, Thomas et al.
Partner: UNT Libraries Government Documents Department

Design, Installation, and Initial Commissioning of the MTA Beamline

Description: A new experimental area designed to develop, test and verify muon ionization cooling apparatus using the 400-MeV Fermilab Linac proton beam has been fully installed and is presently being commissioned. Initially, this area was used for cryogenic tests of liquid-hydrogen absorbers for the MUCOOL R&D program and, now, for high-power beam tests of absorbers, high-gradient rf cavities in the presence of magnetic fields (including gas-filled cavities), and other prototype muon-cooling apparatus. The experimental scenarios being developed for muon facilities involve collection, capture, and cooling of large-emittance, high-intensity muon beams--{approx}10{sup 13} muons, so that conclusive tests of the apparatus require full Linac beam, which is 1.6 x 10{sup 13} p/pulse. To support the muon cooling facility, this new primary beamline extracts and transports beam directly from the Linac to the test facility. The design concept for the MuCool facility is taken from an earlier proposal [1], but modifications were necessary to accommodate high-intensity beam, cryogenics, and the increased scale of the cooling experiments. Further, the line incorporates a specialized section and utilizes a different mode of operation to provide precision measurements of Linac beam parameters. This paper reports on the technical details of the MuCool beamline for both modes.
Date: May 1, 2010
Creator: Moore, Craig; /Fermilab; Anderson, John; /Fermilab; Garcia, Fernanda; /Fermilab et al.
Partner: UNT Libraries Government Documents Department