[en] The Radio Frequency Quadrupole Accelerator (RFQ) has found wide application, not only as the preinjector linac for new high energy light ion accelerators but also in a variety of other projects. Progress in development has made ion linacs practical for medical and industrial applications including radiation therapy, isotope and neutron production, material modification and ion beam diagnostic. The paper discusses various projects together with applications in science where RFQs serve as stand-alone tools, for example for the calibration of detectors, as decelerators or as small compact beam sources for atomic physics and materials research. (Author) 7 figs., 40 refs

[en] A simple model of RFQ channel is proposed. The model represents the periodic chain of twin point charges with a screw symmetry axis and alternating sign of the charges. For this approach the expressions both for longitudinal and azimuthal potential harmonics are determined in closed forms. The relationship of model parameters with RFQ geometry is defined. The results of calculations for different vane shapes are given including idealized electrodes and electrodes with extremely large modulation

[en] Two Heavy Ion RFQs have been built for the UNILAC at GSI, a new high charge state injector (HLI) and a prototype of a new high current injector (HSI). Both can be seen as branches of actual RFQ development. The HLI-RFQ accelerates U²⁸⁺ ions from an ECR-ion source from 2.5keV/u to 300keV/u with a high duty cycle of now 25% at an operating frequency of 108.5MHz. The Spiral-RFQ for the HSI accelerator accepts low energy (2.2keV/u), high current (25 mA) beams with low charge states (U²⁺, Xe⁺) at an operating frequency of 27 MHz. Results of structure development and beam experiments for both structures are discussed which can be seen as model for the first crucial part of a RFQ for low charged radioactive beams concerning low frequency operation, high duty factor and beam dynamics properties

[en] A 2 MeV, 110 mA, 10% duty, 201.25 MHz RFQ has been designed for the Basic Technology Accelerator (BTA) by Japan Atomic Energy Research Institute. In this report, the design parameters, LEBT study, acceleration efficiency correction due to the two-dimensional vane-tip machining, frequency tuning of the vane-end region and thermal considerations are presented. (Author) 9 refs. 8 figs., tab

[en] Short communication

[en] Radio Frequency Quadrupole (RFQ) structures are well suited to accelerate all kinds of ions at low particle energies with high transmission efficiency even at high beam currents. Like other rf-accelerators they normally have a fixed velocity profile and corresponding fixed input and output energies per nucleon of the accelerated ions. But - due to the strong transverse focusing - the RFQ-accelerators can also capture and transport very efficiently ions with energies and specific charge states even far away from the design values. Results of calculations will be presented and compared to measurements

[en] The PEFP (Proton Engineering Frontier Project) RFQ Accelerator was constructed to accelerate 20-mA CW Proton beam from 50 ke V to 450 ke V. This 350- MHz RFQ is to form with one 98-cm cavity. It is essential that the field distribution meets the design requirement in order to minimize the beam losses. The results of experimental studies on RF characteristics of a four vane RFQ cavity was obtained. A mode separation and field distribution have been obtained with a loop coupler. The tuning procedure was performed by employing the bead-pulling technique. In this technique a metal bead was suspended on a nylon line and drawn through the four quadrants near the RFQ's outer wall. Sixteen Aluminum slug tuners distributed along the outer walls tuned the RFQ. By tuning the positions of 16 slug tuners, a uniform field distribution within errors a few percent both longitudinally and azimuthally were achieved in this RFQ

[en] The Ground Test Accelerator (GTA) uses a radio-frequency quadrupole (RFQ) to bunch and accelerate a 35 keV input beam to a final energy of 2.5 MeV. Most measured parameters of the GTA RFQ agreed with simulated predictions. The relative shape of the transmission versus the vane-voltage relationship and the Courant-Snyder (CS) parameters of the output beam's transverse and longitudinal phase spaces agreed well with predictions. However, the transmission of the RFQ was significantly lower than expected. Improved simulation studies included image charges and multipole effects in the RFQ. Most of the predicted properties of the RFQ, such as input matched-beam conditions and output-beam shapes were unaffected by these additional effects. However, the comparison of measured with predicted absolute values of transmitted beam was much improved by the inclusion of these effects in the simulations. The comparison implied a value for the input emittance that is consistent with measurements

[en] Over the last several years the RFQ has proved to be a very flexible low-energy accelerator for bunching and accelerating both low- and high-current beams. It uses low-voltage dc injectors, has excellent bunching properties and high transmission efficiency. Applications include injectors for higher energy machines, such as drift-tube linacs, cyclotrons, or synchrotrons. The RFQ can also be used alone for applications that require a fixed-energy beam. 41 references, 4 figures, 2 tables

[en] This paper discusses the conceptual design of an Ultrafine Particle Radio Frequency Quadrupole (UFP-RFQ) accelerator. The results indicate that it is possible to accelerate 1 μm radius Al particles to velocities around 100 km/s in 100 m RFQ length. This accelerator can provide variable output particle velocity, with capability of handling different particle materials with different sizes. There are scientific, industrial and space applications in the collisions of such particles with targets