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A generic finite state machine framework for the ACNET control system

Description: A significant level of automation and flexibility has been added to the ACNET control system through the development of a Java-based Finite State Machine (FSM) infrastructure. These FSMs are integrated into ACNET and allow users to easily build, test and execute scripts that have full access to ACNET's functionality. In this paper, a description will be given of the FSM design and its ties to the Java-based Data Acquisition Engine (DAE) framework. Each FSM is part of a client-server model with … more
Date: October 1, 2009
Creator: Carmichael, L. & Warner, A.
Partner: UNT Libraries Government Documents Department
open access

Experimental study of slow-rate transition crossing in AGS

Description: The nonlinear momentum-compaction factor {alpha}{sub 1} has been obtained in the AGS by measuring transition energies at different radial orbits using a low-intensity slow-ramped Au{sup 77+} beam. The beam loss during the transition crossing is found to increase with increasing rf voltage, and to decrease with increasing ramping rate, which indicates that the effect of chromatic nonlinearity (Johnson effect) dominates the transition crossing. The experimental measurement of beam loss agrees ver… more
Date: August 1, 1994
Creator: Wei, J.; Warner, A. & Ahrens, L.
Partner: UNT Libraries Government Documents Department
open access

Cryogenic loss monitors with FPGA TDC signal processing

Description: Radiation hard helium gas ionization chambers capable of operating in vacuum at temperatures ranging from 5K to 350K have been designed, fabricated and tested and will be used inside the cryostats at Fermilab's Superconducting Radiofrequency beam test facility. The chamber vessels are made of stainless steel and all materials used including seals are known to be radiation hard and suitable for operation at 5K. The chambers are designed to measure radiation up to 30 kRad/hr with sensitivity of a… more
Date: September 1, 2011
Creator: Warner, A. & Wu, J.
Partner: UNT Libraries Government Documents Department
open access

Development of a machine protection system for the Superconducting Beam Test Facility at Fermilab

Description: Fermilab's Superconducting RF Beam Test Facility currently under construction will produce electron beams capable of damaging the acceleration structures and the beam line vacuum chambers in the event of an aberrant accelerator pulse. The accelerator is being designed with the capability to operate with up to 3000 bunches per macro-pulse, 5Hz repetition rate and 1.5 GeV beam energy. It will be able to sustain an average beam power of 72 KW at the bunch charge of 3.2 nC. Operation at full intens… more
Date: September 1, 2011
Creator: Warner, A.; Carmichael, L.; Church, M.; Neswold, R. & /Fermilab
Partner: UNT Libraries Government Documents Department
open access

Optimization of electron cooling in the Recycler

Description: Antiprotons in Fermilab's Recycler ring are cooled by a 4.3 MeV, 0.1A DC electron beam (as well as by a stochastic cooling system). The paper describes electron cooling improvements recently implemented: adjustments of electron beam line quadrupoles to decrease the electron angles in the cooling section and better stabilization and control of the electron energy.
Date: April 1, 2009
Creator: Shemyakin, A.; Burov, A.; Carlson, K.; Prost, L. R.; Sutherland, M. & Warner, A.
Partner: UNT Libraries Government Documents Department
open access

Beam profile diagnostics for the Fermilab medium energy electron cooler

Description: The Fermilab Recycler ring will employ an electron cooler to store and cool 8.9 GeV antiprotons. The cooler will be based on a Pelletron electrostatic accelerator working in an energy-recovery regime. Several techniques for determining the characteristics of the beam dynamics are being investigated. Beam profiles have been measured as a function of the beam line optics at the energy of 3.5 MeV in the current range of 10{sup -4}-1 A, with a pulse duration of 2 {micro}s. The profiles were measure… more
Date: July 1, 2005
Creator: Warner, A.; Kazakevich, Grigory M.; Nagaitsev, S.; Tassotto, G.; /Fermilab; Gai, W. et al.
Partner: UNT Libraries Government Documents Department
open access

The design and implementation of the machine protection system for the Fermilab electron cooling facility

Description: The Fermilab Recycler ring employs an electron cooler to store and cool 8.9-GeV antiprotons. The cooler is based on a 4.3-MV, 0.1-A, DC electrostatic accelerator for which current losses have to remain low ({approx}10{sup -5}) in order to operate reliably. The Machine Protection System (MPS) has been designed to interrupt the beam in a matter of 1-2 {micro}s when losses higher than a safe limit are detected, either in the accelerator itself or in the beam lines. This paper highlights the variou… more
Date: May 1, 2009
Creator: Warner, A.; Carmichael, L.; Carlson, K.; Crisp, J.; Goodwin, R.; Prost, L. et al.
Partner: UNT Libraries Government Documents Department
open access

OTR measurements and modeling of the electron beam optics at the E-cooling facility

Description: Optics of the electron beam accelerated in the Pelletron, intended for the electron cooling of 8.9 GeV antiprotons in the Fermilab recycler storage ring, has been studied. The beam profile parameters were measured under the accelerating section using Optical Transition Radiation (OTR) monitor. The monitor employs a highly-reflective 2 inch-diameter aluminum OTR-screen with a thickness of 5 {micro}m and a digital CCD camera. The measurements were done in a pulse-signal mode in the beam current r… more
Date: November 1, 2005
Creator: Warner, A.; Burov, Alexey V.; Carlson, K.; Kazakevich, G.; Nagaitsev, S.; Prost, L. et al.
Partner: UNT Libraries Government Documents Department
open access

Magnetic field measurement and compensation in the Recycler Electron Cooler

Description: Cooling of 8.9-GeV/c antiprotons in the Recycler Electron Cooler requires a round 4.34-MeV electron beam with a small angular spread propagating through a 20-m long cooling section. To confine the electron beam tightly and to keep its total transverse angles below 0.2 mrad the cooling section is immersed in a solenoidal field of 50-200 G. The field was measured with a compass-based sensor (transversal) and a hall-probe (longitudinal) after installation of the solenoids into the Recycler tunnel.… more
Date: September 1, 2005
Creator: Tupikov, V.; Kazakevich, Grigory M.; Kroc, T. K.; Nagaitsev, S.; Prost, L.; Shemyakin, A. et al.
Partner: UNT Libraries Government Documents Department
open access

Supermassive Black Holes and the Strong Field Limit of General Relativity

Description: The energy driving a quasar or active galactic nucleus (AGN) is thought to come from the accretion of gas on to a supermassive black hole at the center of the host galaxy. Evidence for this has been hard to find, but the extremely broad iron line observed in the X-ray spectrum of one particular AGN (the Seyfert galaxy known as MCG-6-30-15) may well be the calling card of a supermassive black hole. A new model-independent approach to analyzing these intriguing X-ray emissions extracts more infor… more
Date: August 1, 2000
Creator: Zurek, Wojciech; Miller, Warner A.; Pariev, Vladimir & Bromley, Benjamin
Partner: UNT Libraries Government Documents Department
open access

Status of high energy electron cooling in FNAL's Recycler Ring

Description: Electron cooling of 8 GeV antiprotons at Fermilab's Recycler storage ring is now routinely used in the collider operation. It requires a 0.1-0.5 A, 4.3 MeV DC electron beam to increase the longitudinal phase-space density of the circulating antiproton beam. This paper discusses the latest status of the electron cooler and its mode of operation within the context of Fermilab's accelerator complex. In addition, we will show preliminary results that demonstrate electron cooling of the transverse p… more
Date: September 1, 2006
Creator: Prost, Lionel R.; Burov, A.; Carlson, K.; Gattuso, C.; Hu, M.; Nagaitsev, S. et al.
Partner: UNT Libraries Government Documents Department
open access

Optics of electron beam in the Recycler

Description: Electron cooling of 8.9 GeV/c antiprotons in the Recycler ring (Fermilab) requires high current and good quality of the DC electron beam. Electron trajectories of {approx}0.2 A or higher DC electron beam have to be parallel in the cooling section, within {approx}0.2 mrad, making the beam envelope cylindrical. These requirements yielded a specific scheme of the electron transport from a gun to the cooling section, with electrostatic acceleration and deceleration in the Pelletron. Recuperation of… more
Date: November 1, 2005
Creator: Burov, Alexey V.; Kazakevich, G.; Kroc, T.; Lebedev, V.; Nagaitsev, S.; Prost, L. et al.
Partner: UNT Libraries Government Documents Department
open access

Time in quantum geometrodynamics

Description: Standard techcniques of canonical gravity quantization on the superspace of 3-metrics are known to causc insurmountable difficulties in the description of time evolution. We forward a new quantization procedure on the superspace of true dynamic variables - geometrodynamic quantization. The procedure takes into account the states that are off shell with respect to the constrainls and thus circumvents the notorious problems of time. In this approach, quantum geometrodynamics, general covariance, … more
Date: January 1, 2002
Creator: George, Nathan D.; Gentle, Adrian P.; Kheyfets, Arkady & Miller, Warner A.
Partner: UNT Libraries Government Documents Department
open access

Performance of the Fermilab's 4.3 MeV electron cooler

Description: A 4.3 MeV DC electron beam is used to cool longitudinally an antiproton beam in the Fermilab's Recycler ring. Cooling capabilities of the electron beam are characterized by the drag rate that was measured at various conditions. Fitting the results with a formula for non-magnetized cooling gives electron parameters that agree within a factor of 2 with independently measured electron beam properties.
Date: June 1, 2006
Creator: Shemyakin, A.; Burov, Alexey V.; Carlson, K.; Hu, M.; Kroc, T.; Leibfritz, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Enhanced Computational Infrastructure for Data Analysis at the DIII-D National Fusion Facility

Description: The DIII-D National Team consists of about 120 operating staff and 100 research scientists drawn from 9 U.S. National Laboratories, 19 foreign laboratories, 16 universities, and 5 industrial partnerships. This multi-institution collaboration carries out the integrated DIII-D program mission which is to establish the scientific basis for the optimization of the tokamak approach to fusion energy production. Presently, about two-thirds of the research physics staff are from the national and intern… more
Date: July 1, 1999
Creator: Schissel, D. P.; Peng, Q.; Schachter, J.; Tepstra, T. B.; Casper, T. A.; Freeman, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Electron cooling of 8-GeV antiprotons at Fermilab's Recycler: Results and operational implications

Description: Electron cooling of 8 GeV antiprotons at Fermilab's Recycler storage ring is now routinely used in the collider operation. It requires a 0.1-0.5 A, 4.3 MeV dc electron beam and is designed to increase the longitudinal phase-space density of the circulating antiproton beam. This paper briefly describes the characteristics of the electron beam that were achieved to successfully cool antiprotons. Then, results from various cooling force measurements along with comparison to a nonmagnetized model a… more
Date: May 1, 2006
Creator: Prost, L.R.; Broemmelsiek, D.; Burov, Alexey V.; Carlson, K.; Gattuso, C.; Hu, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Experimental demonstration of relativistic electron cooling

Description: We report on an experimental demonstration of electron cooling of high-energy antiprotons circulating in a storage ring. In our experiments, electron cooling, a well-established method at low energies (< 500 MeV/nucleon), was carried out in a new region of beam parameters, requiring a multi-MeV dc electron beam and an unusual beam transport line. In this letter we present the results of the longitudinal cooling force measurements and compare them with theoretical predictions.
Date: November 1, 2005
Creator: Nagaitsev, S.; Broemmelsiek, D.; Burov, Alexey V.; Carlson, K.; Gattuso, C.; Hu, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Attainment of a high-quality electron beam for Fermilab's 4.3 MeV cooler

Description: The recent demonstration of electron cooling of antiprotons in the Recycler ring required a stable 4.3 MeV electron beam with a DC current of hundreds of mA and an angular spread in the cooling section of a fraction of a mrad. This paper describes the achieved parameters of the Fermilab cooler's electron beam and details of operation.
Date: November 1, 2005
Creator: Shemyakin, A.; Burov, Alexey V.; Carlson, K.; Hu, M.; Kazakevich, G.; Kramper, B. et al.
Partner: UNT Libraries Government Documents Department
open access

Commissioning of Fermilab's electron cooling system for 8-GeV antiprotons

Description: A 4.3-MeV electron cooling system [1] has been installed at Fermilab in the Recycler antiproton storage ring and is currently being commissioned. The cooling system is designed to assist accumulation of 8.9-GeV/c antiprotons for the Tevatron collider operations. This paper reports on the progress of the electron beam commissioning effort as well as on detailed plans of demonstrating the cooling of antiprotons.
Date: May 1, 2005
Creator: Nagaitsev, S.; Broemmelsiek, D.; Burov, A.; Carlson, K.; Gattuso, C.; Hu, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Antiproton cooling in the Fermilab Recycler Ring

Description: The 8.9-GeV/c Recycler antiproton storage ring is equipped with both stochastic and electron cooling systems. These cooling systems are designed to assist accumulation of antiprotons for the Tevatron collider operations. In this paper we report on an experimental demonstration of electron cooling of high-energy antiprotons. At the time of writing this report, the Recycler electron cooling system is routinely used in collider operations. It has helped to set recent peak luminosity records.
Date: December 1, 2005
Creator: Nagaitsev, S.; Bolshakov, A.; Broemmelsiek, D.; Burov, Alexey V.; Carlson, K.; Gattuso, C. et al.
Partner: UNT Libraries Government Documents Department
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