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On the calibration of TEVATRON beam position and intensity monitors used in E778

Description: In the second run of E778 two sets of electronics were used to record the motion of the center of mass of the beam. The first, the standard Fermilab Beam Position Monitor (BPM) front end, gives direct horizontal, vertical and intensity signals. The second is a peak sensing circuit which gives signals from the separate plates of two horizontal and one vertical pickup. This note addresses the question of calibration of the signals from the standard Tevatron beam position (HF42 and HF44 in the cas… more
Date: May 1, 1988
Creator: Merminga, L.; Gerig, R. & Peggs, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Energy spread from rf amplitude and phase errors

Description: The energy spread in the beam due to rf amplitude and phase errors is calculated for multiple passes and off-crest operation. Effects of the slow phase errors and feedback systems are included in the calculation. If an rms energy spread requirement is to be met, a final formula gives the tradeoff between slow and fast phase errors and amplitude errors. Phase and amplitude stability requirements are derived for CEBAF IR DEMO FEL (free electron laser).
Date: July 1, 1996
Creator: Merminga, L. & Kraft, G. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Energy stability in a high average power FEL

Description: Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs. Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, or, when coupled to M{sub 56}, phase oscillations. Both effects change the beam induced voltage in the cavities and can lead to unstable variations of the accelerating field. Stability analysis for small perturbations from equilibrium is performed and threshold currents … more
Date: December 31, 1995
Creator: Merminga, L. & Bisognano, J.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Energy spread from rf amplitude and phase errors

Description: The energy spread in the beam due to rf amplitude and phase errors is calculated for multiple passes and off-crest operation. Effects of the slow phase errors and feedback systems are included in the calculation. If an rms energy spread requirement is to be met, a final formula gives the tradeoff between slow and fast phase errors and amplitude errors. Phase and amplitude stability requirements are derived for CEBAF IR DEMO FEL (free electron laser).
Date: July 1, 1996
Creator: Merminga, L. & Kraft, G.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Energy stability in recirculating, energy-recovering linacs in the presence of a FEL

Description: Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs (free electron lasers). Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, or, when coupled to M{sub 56}, phase oscillations. Both effects change the beam induced voltage in the cavities and can lead to unstable variations of the accelerating field. An analytical model which includes amplitude and phase feedback, has been… more
Date: July 1, 1996
Creator: Merminga, L.; Bisognano, J. & Delayen, J. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Energy stability in recirculating, energy-recovering linacs in the presence of a FEL

Description: Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs (free electron lasers). Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, or, when coupled to M{sub 56}, phase oscillations. Both effects change the beam induced voltage in the cavities and can lead to unstable variations of the accelerating field. An analytical model which includes amplitude and phase feedback, has been… more
Date: July 1, 1996
Creator: Merminga, L.; Bisognano, J. & Delayen, J.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Beam breakup in a microtron

Description: In a microtron, the path length change from pass to pass is a fixed multiple of the RF wavelength, and the accelerating system can be reasonably well approximated as a single cavity. Under such circumstances it is possible to derive an analytical formula for the multipass beam breakup threshold current. The threshold current determined by numerical simulations agrees very well with the formula for a machine with a small number of passes. The analytic formula can serve as a useful guide in exami… more
Date: June 1, 1997
Creator: Yung, B.C. & Merminga, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Higher-Order-Modes and beam breakup simulations in the Jefferson Lab FEL recirculating linac

Description: Measurements were performed of the frequencies and external Q's of the first two Higher-Order Mode (HOM) dipole passbands in the eight superconducting cavities of the cryomodule used in the recirculating linac of the driver accelerator of Jefferson Lab's IR FEL. Anomalous high-Q resonances were found, which could lead to beam instabilities at currents close to the operating current of the machine. These results led to more detailed simulations of its beam breakup (BBU) behavior. The analysis in… more
Date: August 1, 1998
Creator: Merminga, L. & Campisi, R.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Energy stability in recirculating, energy-recovering linacs

Description: Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs. Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, or, when coupled to M{sub 56}, phase oscillations. Both effects change the beam induced voltage in the cavities and can lead to unstable variations of the accelerating field. Stability analysis for small perturbations from equilibrium is performed and threshold currents … more
Date: July 1, 1996
Creator: Merminga, L.; Bisognano, J.J. & Delayen, J.R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Rf system modeling for the high average power FEL at CEBAF

Description: High beam loading and energy recovery compounded by use of superconducting cavities, which requires tight control of microphonic noise, place stringent constraints on the linac rf system design of the proposed high average power FEL at CEBAF. Longitudinal dynamics imposes off-crest operation, which in turn implies a large tuning angle to minimize power requirements. Amplitude and phase stability requirements are consistent with demonstrated performance at CEBAF. A numerical model of the CEBAF r… more
Date: December 31, 1995
Creator: Merminga, L.; Fugitt, J.; Neil, G. & Simrock, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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An Energy Recovery Electron Linac-on-Proton Ring Collider

Description: Electron-proton colliders with center of mass energies between 14 GeV and 30 GeV and luminosities at the 10{sup 33} level have been proposed recently as a means for studying hadronic structure [1]. Electron beam polarization appears to be crucial for the majority of experiments. Two accelerator design scenarios have been examined in detail: colliding rings [2] and recirculating linac-on-ring [3]. Although the linac-on-ring scenario is not as well understood as the ring-ring scenario, comparable… more
Date: March 1, 2001
Creator: Merminga, L.; Krafft, G. & Lebedev, V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A design and performance analysis tool for superconducting RF systems

Description: Superconducting rf systems are usually operated with continuous rf power or with rf pulse lengths exceeding 1 ms to maximize the overall wall plug power efficiency. Typical examples are CEBAF at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) and the TESLA Test Facility at DESY. The long pulses allow for effective application of feedback to stabilize the accelerating field in presence of microphonics, Lorentz force detuning, and fluctuations of the beam current. In this paper… more
Date: May 1, 1997
Creator: Schilcher, T.; Simrock, S. N.; Merminga, L. & Wang, D. X.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Beam breakup simulations for the Jefferson Lab FEL upgrade

Description: As the Jefferson Lab Free Electron Laser steadily approaches its goal of producing 1 kW of IR radiation at 5 mA of beam current at 42 MeV, plans are being considered for possible upgrade scenarios, which will extend the IR power output and allow generation of UV radiation. The upgrade scenario presently considered will bring the beam current to 10 mA and increase the energy to values close to 200 MeV. These parameters will most likely be realized in a machine configuration with a single recircu… more
Date: April 1, 1999
Creator: Campisi, I.E.; Douglas, D.; Merminga, L. & Yunn, B.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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RF Control Requirements for the CEBAF Energy Upgrade Cavities

Description: The 6 GeV CEBAF accelerator at Jefferson Lab is arranged in a five-pass racetrack configuration, with two superconducting radio frequency (SRF) linacs joined by independent magnet transport arcs. It is planned to increase the accelerator energy to eventually support 12 GeV operations. To achieve this, a new 7-cell superconducting cavity is being built to operate at an average accelerating gradient of 12.5 MV/m with an external Q of 2.2 x 10{sup 7}. The present RF system, composed of an analog c… more
Date: August 1, 2000
Creator: Hovater, C.; Delayen, J.; Merminga, L.; Powers, T. & Reece, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Specifying HOM-Power Extraction in a High Average Current Short Bunch Length SRF Environment

Description: High average current, short bunch length beams in superconducting cavities can excite significant amounts of higher-order mode (HOM) power. The fraction that is dissipated in the cavity walls is of primary relevance as it can potentially limit the peak and average current due to the finite cryogenic capacity. A model has been developed which estimates the amount of power dissipated on the walls based on the dependence of the cavity's quality factor Q on frequency, due to BCS losses, and an anal… more
Date: August 1, 2000
Creator: Merminga, L.; Krafft, G.; Leemann, C.; Sundelin, R. & Bisognano, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A low-cost, Nist-traceable, high performance dielectric resonator Master Oscillator

Description: The current CEBAF Master Oscillator (MO) uses a quartz-based 10 MHz reference to synthesize 70 MHz and 499 MHz, which are then distributed to each of the klystron galleries on site. Due to the specialized nature of CEBAF's MO requirements, it has been determined that an in-house design and fabrication would provide a cost-effective alternative to purchasing or modifying vendor equipment. A Global Positioning System (GPS) disciplined, Direct Digital Synthesis (DDS) based MO is proposed which inc… more
Date: May 1, 1999
Creator: Doolittle, L.R.; Hovater, C.; Merminga, L.; Musson, J. & Wiseman, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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An energy recovery electron linac-on-ring collider

Description: We present the design of high-luminosity electron-proton/ion colliders in which the electrons are produced by an Energy Recovering Linac (ERL). Electron-proton/ion colliders with center of mass energies between 14 GeV and 100 GeV (protons) or 63 GeV/A (ions) and luminosities at the 10{sup 33}(per nucleon) level have been proposed recently as a means for studying hadronic structure. The linac-on-ring option presents significant advantages with respect to: (1) spin manipulations (2) reduction of … more
Date: September 14, 2000
Creator: Merminga, L.; Krafft, G. A.; Lebedev, V. A. & Ben-Zvi, Ilan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Issues in Acceleration of A Muon Beam for a Neutrino Factory

Description: We have developed a concept for acceleration of a large phase-space, pulsed muon beam from 190 MeV to 50 GeV as part of a collaborative study of the feasibility of a neutrino factory based on in-flight decay of muons. The muon beam's initial energy spread was {approximately}20% and each bunch has the physical size of a soccer ball. Production of the muons will be quite expensive, so prevention of loss due to scraping or decay is critical. The former drives the system to large apertures and the … more
Date: June 1, 2001
Creator: Delayen, J.; Douglas, D.; Harwood, L.; Lebedev, V.; Leemann, C. & Merminga, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The CEBAF beam loss sensors

Description: The CEBAF beam can burn through the vacuum wall in approximately 100 {mu}s. The authors have developed an inexpensive beam loss sensor that will unambiguously detect a true beam loss and shut off the beam within this time without tripping on moderate interference from other sources. They have incorporated a full system test into the system, with provision for direct replacement of faulty sensors without adjustment. They describe the sensors, the signal processing design, system test results, an… more
Date: May 1, 1993
Creator: Perry, J.; Woodworth, E.; Merminga, L.; Simrock, S.; May, R. & Stapleton, G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High Average Current Effects in Energy Recovery Linacs

Description: Energy Recovery Linacs (ERLs) can be used as high efficiency driver accelerators for Free Electron Lasers, synchrotron radiation light sources and colliders. Energy recovery has been successfully demonstrated up to 5 mA of average current in the Jefferson Lab 1.7 kW IRFEL. Future designs call for much higher average currents of order 100 mA. A number of phenomena can potentially limit the performance of ERLs at these high currents. These effects include single and multibunch Beam Breakup, Highe… more
Date: June 1, 2001
Creator: Merminga, L.; Campisi, I.E.; Douglas, D.; Krafft, G.; Preble, J. & Yunn, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Beam current limitations in the Jefferson Lab FEL: Simulations and analysis of proposed beam breakup experiments

Description: A series of beam experiments is being planned in the Jefferson Lab FEL driver accelerator in order to study multi-pass beam breakup instabilities in the machine and to test the predictions of the numerical code TDBBU. The tests are extensions of previously performed or proposed experiments, and will be considerably more sensitive with the present configuration. The experiments will include: (a) observing the onset of instabilities by lowering the threshold current through manipulation of the be… more
Date: April 1, 1999
Creator: Campisi, I. E.; Douglas, D.; Hovater, C.; Krafft, G. A.; Merminga, L. & Yunn, B. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Driver Accelerator Design for the 10 KW upgrade of the Jefferson Lab IR FEL

Description: An upgrade of the Jefferson Lab IR FEL [1] is now under construction. It will provide 10 kW output light power in a wavelength range of 2--10 {micro}m. The FEL will be driven by a modest sized 80--210 MeV, 10 mA energy-recovering CW superconducting RF (SRF) linac. Stringent phase space requirements at the wiggler, low beam energy, and high beam current subject the design to numerous constraints. These are imposed by the need for both transverse and longitudinal phase space management, the poten… more
Date: August 1, 2000
Creator: Douglas, D.; Benson, S.V.; Krafft, G. A.; Li, R.; Merminga, L. & Yunn, B.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Operation of the CEBAF Linac with High Beam Loading

Description: The superconducting RF, CW CEBAF accelerator will use a pair of antiparallel 400 MeV linacs connected by recirculation arcs for nominal 4 GeV in five passes. Single-pass, high power testing of the first linac has been conducted during the months preceding the conference. The RF control system [1] has been designed to control cavity gradient and phase under a wide range of gradients and significant beam loading. At full beam current, accelerating gradient is approximately equal to accelerating v… more
Date: May 1, 1993
Creator: Merminga, L.; Bisognano, J. J.; Hovater, C.; Krafft, G. A.; Simrock, S. N. & Kubo, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Energy Recovery Linac (ERL) as a Driver for X-ray Producing Insertion Devices

Description: Storage rings have served well as x-ray sources, achieving continued increases in flux and brightness. While further improvements in performance may still be expected, the performance of these machines is circumscribed by radiation fluctuations and by the Touschek effect. The practical effect of the radiation fluctuations is to limit the minimum 6D emittance of the rings in general, particularly the bunch length. Through limiting the lifetime, the Touschek effect also limits the charge density … more
Date: June 1, 2001
Creator: Tigner, M.; Bazarov, Ivan; Bilderback, D.; Gruner, S.; Padamsee, H.; Krafft, G. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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