[en] An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis

No abstract available

[en] Three prototype cavities for the side-coupled accelerating structure of Fermilab's Linac Upgrade have been powered. The cavities operate at a nominal maximum surface electric field of 37--42 MV/m and have been run at close to 60 MV/m at 805 MHz. This paper will present the experience accumulated on x-ray production and RF breakdown frequency. We will try to compare our data with others' experiences with high surface electric fields. 5 refs., 3 figs

[en] The 805 MHz Side-coupled cavity modules for the Fermilab 400 MeV linac upgrade have been conditioned to accept full power. The sparking rate in the cavities and in the side-cells has been reduced to acceptable levels. It required approximately 40 x 10⁶ pulses for each module to achieve an adequately low sparking rate. This contribution outlines the commissioning procedure, presents the sparking rate improvements and the radiation level improvements through the commissioning process and disc the near-online commissioning plans for this accelerator

[en] The two H = 84 stacking/buching cavities in the P-bar Accumulator Storage Ring operating at 52.812 MHz are required for beam stability to have a Z/n = 350 each. The cavities are operated in two modes: in a long pulse high power mode (250 ms every 2.1 s) to stack and bunch the beam in normal P-bar Source operation, and in a CW mode at moderate power level for aperture diagnostic studies. Furthermore, future internal target experiments in the Accumulator require this to be accomplished over a frequency range of -18%. The above require that the Q-swamping technique be broadband and robust. This has been accomplished by magnetic field loop coupling and electric field capacitive coupling of EM fields from the high Q cavity to external high power water cooled 50 ohm coaxial loads. The tuning has been accomplished by movable large metal slugs, two per cavity

[en] In order to increase the beam capture efficiency of Argonne's heavy-ion linac to over 70%, a single cavity harmonic buncher has been designed as a replacement for the existing fundamental frequency buncher. Because the beam line space between the 1.5-MeV Xe⁺₁ preaccelerator and first accelerating cavity is at a premium, especially in the tunnel area near the preaccelerator, a single-cavity design was undertaken. In addition, to further conserve access space, the cavity was designed to fit directly beneath the beam line. The cavity is designed to resonate at the fundamental linac frequency of 12.5 MHz and its first harmonic, 25 MHz. This was accomplished by nesting the 25-MHz resonant section inside the larger 12.5-MHz resonant section. Both sections are heavily capacitively loaded, folded coaxial lines with two 0.008-m accelerating gaps per section. The cavity was designed using a transmission line model taking account of the capacitances of each discontinuity and by use of the RF cavity computer program Superfish. The transit time factor for the cavity gaps was calculated using the computer program Poisson and are 0.44 for the 25-MHz section and 0.70 for the 12.5 MHz section. The transit time factors are poor because of the large linac aperture of 0.049 m

[en] In synchrotrons for ion beam fusion one needs a small bucket area to limit the longitudinal emittance, a small synchrotron frequency to avoid synchrobetatron resonance, a large bunching factor to reduce space charge tune depression, and a high synchronous voltage to complete acceleration without ion-ion collisions. It is proposed to use a trigometric series approximation to a new shed-like waveform to replace the usual pure sine wave (fundamental). The shed waveform divides the interval (O,2π) into two parts with a crossing in between. The right portion contains the particles and is linear, while the left portion is merely an area dump. A fit to a shed with three properly phased sine waves is demonstrated to give almost as good results as the original. In the present application a fundamental frequency range 12.5 to 50.0 MHz is required. Four cavities and four rf systems are utilized to produce the fundamental and two harmonics up to 150 MHz. The frequency range limit of a cavity is imposed by properties of the ferrite, voltage requirement, and the operating frequency. Each cavity covers a factor of 3 in frequency. A dropping down scheme is described so that a single cavity may be used in more than one range

[en] The results for a number of ohmic heating (OH) coil arrangements which will allow the reduction of the major radius of Experimental Power Reactor (EPR) tokamaks will be given. In each case the results are compared, at least indirectly, to the reference case, which has the OH solenoid inside the central core of the reactor. The goal for the alternate geometries studied was to stay within the requirements imposed by the EPR conditions on the plasma and to produce as much or more OH V-s as the reference case

[en] The high energy portion of the Fermilab 400 MeV Linac is made of high gradient (37 MV/meter surface field) side-coupled cavity section which were conditioned over a 10 month period before their installation in August of 1993. We have continued to monitor the conditioning of these cavities since that time while the cavities have been operation, and those results are presented here. The sparking rate and the X-ray production are measured and compared with the 1992/1993 pre-operational and 1993/1994 early operational measurements. These rates are consistent with a continued diminishing of these phenomena. Predictions and spark management strategies presented in earlier reports are evaluated in light of present experiences. We also have been measuring the sparking rate within this structure with and without our 50 mA peak beam. We find that the sparking rate is 20% higher with beam in the accelerator

[en] Standard operating procedures are presented for the vacuum, cryogenic, and electronic systems of a polarized proton target. The systems are comprised of (1) a target cryostat; (2) a ⁴He pumping system; (3) a ³He pumping system; (4) a microwave system; (5) a magnet and power supply; (6) a computerized polarization monitor; and (7) miscellaneous auxiliary equipment