arXiv subjects

D. Wildman

Publications and source records attributed to D. Wildman.

8 recordsLinked to original sources

arXiv2014

Perpendicularly Biased YIG Tuners for the Fermilab Recycler 52.809 MHz Cavities

For NOvA and future experiments requiring high intensity proton beams, Fermilab is in the process of upgrading the existing accelerator complex for increased proton production. One such improvement is to reduce the Main Injector cycle time, by performing slip stacking, previously done in the Main Injector, in the now repurposed Recycler Ring. Recycler slip stacking requires new tuneable RF cavities, discussed separately in these proceedings. These are quarter wave cavities resonant at 52.809 MHz with a 10 kHz tuning range. The 10 kHz range is achieved by use of a tuner which has an electrical length of approximately one half wavelength at 52.809 MHz. The tuner is constructed from 3 1/8 inch diameter rigid coaxial line, with 5 inches of its length containing perpendicularly biased, Al doped Yttrium Iron Garnet (YIG). The tuner design, measurements, and high power test results are presented.

physics.acc-ph↗

arXiv2014

Design and High Power Testing of 52.809 MHz RF Cavities for Slip Stacking in the Fermilab Recycler

For NOvA and future experiments requiring high intensity proton beams, Fermilab is in the process of upgrading the existing accelerator complex for increased proton production. One such improvement is to reduce the Main Injector cycle time, by performing slip stacking, previously done in the Main Injector, in the now repurposed Recycler Ring. Recycler slip stacking requires two new RF cavities operating at slightly different frequencies (df = 1260Hz). These are copper, coaxial, quarter wave cavities with R/Q =13 ohms. They operate at a peak gap voltage of 150 kV with 150 kW peak drive power (60% duty factor), and are resonant at 52.809 MHz with a 10 kHz tuning range. Two have been completed and installed. The design, high power test results, and status of the cavities are presented.

physics.acc-ph↗

arXiv2013

The Six-Cavity Test - Demonstrated Acceleration of Beam with Multiple RF Cavities and a Single Klystron

The High Intensity Neutrino Source (HINS) Six-Cavity Test has demonstrated the use of high power RF vector modulators to control multiple RF cavities driven by a single high power klystron to accelerate a non-relativistic beam. Installation of 6 cavities in the existing HINS beamline has been completed and beam measurements have started. We present data showing the energy stability of the 7 mA proton beam accelerated through the six cavities from 2.5 MeV to 3.4 MeV.

physics.acc-ph↗

arXiv2012

Status and specifications of a Project X front-end accelerator test facility at Fermilab

This paper describes the construction and operational status of an accelerator test facility for Project X. The purpose of this facility is for Project X component development activities that benefit from beam tests and any development activities that require 325 MHz or 650 MHz RF power. It presently includes an H- beam line, a 325 MHz superconducting cavity test facility, a 325 MHz (pulsed) RF power source, and a 650 MHz (CW) RF power source. The paper also discusses some specific Project X components that will be tested in the facility.

physics.acc-ph↗

arXiv2012

First high power pulsed tests of a dressed 325 MHz superconducting single spoke resonator at Fermilab

In the recently commissioned superconducting RF cavity test facility at Fermilab (SCTF), a 325 MHz, β=0.22 superconducting single-spoke resonator (SSR1) has been tested for the first time with its input power coupler. Previously, this cavity had been tested CW with a low power, high Qext test coupler; first as a bare cavity in the Fermilab Vertical Test Stand and then fully dressed in the SCTF. For the tests described here, the design input coupler with Qext ~ 106 was used. Pulsed power was provided by a Toshiba E3740A 2.5 MW klystron.

physics.acc-ph↗

arXiv2012

Experiences with the Fermilab HINS 325 MHz RFQ

The Fermilab High Intensity Neutrino Source program has built and commissioned a pulsed 325 MHz RFQ. The RFQ has successfully accelerated a proton beam at the RFQ design RF power. Experiences encountered during RFQ conditioning, including the symptoms and cause of a run-away detuning problem, and the first beam results are first reported.

physics.acc-ph↗

arXiv2008

Fast beam stacking using RF barriers

Two barrier RF systems were fabricated, tested and installed in the Fermilab Main Injector. Each can provide 8 kV rectangular pulses (the RF barriers) at 90 kHz. When a stationary barrier is combined with a moving barrier, injected beams from the Booster can be continuously deflected, folded and stacked in the Main Injector, which leads to doubling of the beam intensity. This paper gives a report on the beam experiment using this novel technology.

physics.acc-ph↗

arXiv2008

Experimental Studies of Compensation of Beam-Beam Effects with Tevatron Electron Lenses

Applying the space-charge forces of a low-energy electron beam can lead to a significant improvement of the beam-particle lifetime limit arising from the beam-beam interaction in a high-energy collider [1]. In this article we present the results of various beam experiments with electron lenses, novel instruments developed for the beam-beam compensation at the Tevatron, which collides 980-GeV proton and antiproton beams. We study the dependencies of the particle betatron tunes on the electron beam current, energy and position; we explore the effects of electron-beam imperfections and noises; and we quantify the improvements of the high-energy beam intensity and the collider luminosity lifetime obtained by the action of the Tevatron Electron Lenses.

physics.acc-ph↗