Beam dynamics studies on the ISAC RFQ at TRIUMF

Koscielniak, Shane; Laxdal, Robert; Lee, R.; Root, L.

doi:10.1109/pac.1997.749942

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…The particles that survive these output cuts are recorded and used to map out the corresponding input admittance of the machine. Although a wide variety of cases has been considered and is reported elsewhere [17,18], here we present two indicative cases using 200 and 100 MHz rf and describe the important trends in machine performance.…”

Section: Simulations Of Longitudinal Dynamicsmentioning

confidence: 99%

FFAGS for rapid acceleration

Johnstone

Koscielniak

2003

Nuclear Instruments and Methods in Physics Research Section A:

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When large transverse and longitudinal emittances are to be transported through a circular machine, extremely rapid acceleration holds the advantage that the beam becomes immune to nonlinear resonances because there is insufficient time for amplitudes to build up. Uncooled muon beams exhibit large emittances and require fast acceleration to avoid decay losses and would benefit from this style of acceleration. The approach here employs a fixed-field alternating gradient or FFAG magnet structure and a fixed frequency acceleration system. Acceptance is enhanced by the use only of linear lattice elements, and fixed-frequency rf enables the use of cavities with large shunt resistance and quality factor.

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Section: Simulations Of Longitudinal Dynamicsmentioning

confidence: 99%

FFAGS for rapid acceleration

Johnstone

Koscielniak

2003

Nuclear Instruments and Methods in Physics Research Section A:

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“…This is because the beam required by the RFQ is highly convergent (28 mrad), and a short final quad avoids the beam being overly large in the second-tolast quad in the direction of defocusing in the final quad. The matching section and the shapes of the electrodes at the RFQ entrance were optimized together [4]. Laplace's equation was solved for a given electrode shape, particles were tracked to find the acceptance ellipses, an optimal matching section was designed as described above by minimizing the 3 rd order quad aberrations; then a new RFQ configurationwas calculated again and the procedure repeated.…”

Section: Optics Modulesmentioning

confidence: 99%

60 keV beam transport line and switch-yard for ISAC

Baartman

Welz²

Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167)

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The ISAC project under construction at TRIUMF [1] is to consist of radioactive ion sources, a high resolution mass separator, a low-energy (60 keV) experimental area, RFQ and DTL linacs to reach 1.5 MeV per atomic mass unit (amu), and a high-energy experimental area. Additionally, there will be a stable off-line source primarily for commissioning the linacs but also for use by the low-energy experimental program. The transport line which connects these elements therefore includes a switch which allows either the radioactive beam to supply the low energy area simultaneously with the off-line source supplying the RFQ, or the radioactive beam supplying beam to the RFQ simultaneously with the off-line source supplying beam to the low-energy experiments. The maximum ion source voltage is 60 kV. The RFQ accepts particles with 2 keV per amu, so masses less than 30 must have lower energy and masses larger than 30 can only be accelerated if they are multiplycharged. All optics is electrostatic; the bends have spherical electrodes. Alignment tolerances are given. Aberrations are kept sufficiently small that the maximum beam emittance of 50 πmm-mrad is transported with negligible distortion. Of particular interest are the achromatic bend sections, the sawtooth buncher insertion, and the matching section to the RFQ. BEAM PROPERTIESFor acceleration in the RFQ, particles must have a velocity corresponding to 2 keV per amu. The lightest mass considered will be 6 amu; therefore the smallest momentum is Bρ = 386 gauss-m.After considering variously reported emittances for radioactive ion sources, we have chosen 50 πmm-mrad as the upper limit nominal emittance. This means we desire to be able to transport this emittance easily with negligible degradation. In practical terms, this means that the acceptance of the transport system should be at least 200 πmm-mrad.In some cases, the beam after the separator may have a much smaller emittance in the bend plane than in the nonbend plane. Somewhat arbitrarily, we impose the condition that for an emittance ratio of 25, the smaller emittance be allowed to increase by no more than 20%.The intensity of the radioactive beam is not envisaged to exceed 1 µA, so space charge is not important. OPTICS ELEMENTSAll optics will be electrostatic. This is cheaper than magnetic, but also simpler to tune since the settings depend only upon beam energy, and not on mass. One can go from one mass to another by simply changing the separator dipole, without retuning the quadrupoles and electrostatic bends in LEBT. The voltages are not high, since the highest beam energy is only 60 keV.At TRIUMF, we have been using electrostatic optics since 1974 in our 20 m long, 300 keV, H − injection line for the cyclotron (ISIS) [2].The ISAC LEBT quadrupoles will be similar to the ISIS quads, with a bore radius of 25 mm. Typical lengths will be 50 mm as opposed to the ISIS standard length of 100 mm. For the typical focal length f = 0.3 m, the required electrode voltage is 2.5 kV at the maximum beam energy of 60 keV....

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“…A unique feature of the design is the constant synchronous phase of -25 ae [3]. The buncher and shaper sections of the RFQ have been eliminated in favour of a four-harmonic sawtooth pre-buncher located ऎ5 m upstream of the RFQ in the low energy beam transport (LEBT).…”

Section: Introductionmentioning

confidence: 99%

Beam test results with the ISAC 35 MHz RFQ

Laxdal¹,

Baartman²,

Root³

Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)

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The ISAC 35 MHz split-ring RFQ is designed to accelerate ions of A=q ऊ 30 from 2 keV/u to 150 keV/u in cw mode at a constant synchronous phase of ,25 ae . Beam tests with 7 of the 19 split rings installed (E aen = 0 :55 keV/u) have recently been completed. The tests demonstrated that a constant synchronous phase RFQ with external buncher works splendidly for low beta, low intensity applications. One peculiar aspect of the RFQ is that the longitudinal acceptance is larger for beams injected off-center. The test set-up and results of both the measurements and the simulations are presented and discussed.

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Beam dynamics studies on the ISAC RFQ at TRIUMF

Cited by 7 publications

References 4 publications

FFAGS for rapid acceleration

FFAGS for rapid acceleration

60 keV beam transport line and switch-yard for ISAC

Beam test results with the ISAC 35 MHz RFQ

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