COMA - A Linear Motion Code for Cyclotrons

Kost, C. J.; Mackenzie, G. H.

doi:10.1109/tns.1975.4328029

Cited by 10 publications

(6 citation statements)

References 2 publications

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“…We implement the space charge force into a linear motion code for cyclotrons, COMA, 16 and simulate the space charge effect using the same parameters as the theory. In this section, our theory model is used to predict the cluster number and growth rate of the instability in CYCIAE-100.…”

Section: E Application Of Our Theory To Cyciae-100mentioning

confidence: 99%

Analytic model for the breakup of a coasting beam with space charge in isochronous accelerators

Zhang

Tang

et al. 2010

Journal of Applied Physics

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An analytical model based on the negative mass instability is introduced in this paper to explain the formation of the breakup of a coasting beam into small clusters in isochronous machines such as the case observed by Pozdeyev and Rodriguez in a small isochronous ring. Solving Poisson's equation in both charge and vacuum regions with the longitudinal beam density perturbation, the coherent radial space charge force which decreases the transition gamma is obtained. It is found that the modified transition gamma depends on the wave number of the density perturbation, longitudinal beam density distribution, beam intensity, and beam size. By combining the longitudinal space charge force caused by the perturbation and the modified transition gamma, a dispersion relation for a monoenergetic beam is derived and evaluated for the fastest-growing instability mode in terms of the beam parameters, such as energy, bunch length, intensity, and emittance. The fastest-growing negative mass mode number, which determines not only the cluster number but also the growth rate of the instability, is proportional to the orbit radius and inversely proportional to the initial beam size. With the growth of the instability, the particles at the points of local minimum density move to the ones of local maximum density, with the transition gamma increasing. Since the growth rate depends on the longitudinal density distribution, therefore, instead of a constant growth rate, our model shows that the growth rate decreases with time. The results above can be applied to both short and long wavelength limits. As an important application of this theory, the beam breakup effect in the isochronous cyclotron CYCIAE-100 is predicted.

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Section: E Application Of Our Theory To Cyciae-100mentioning

confidence: 99%

Analytic model for the breakup of a coasting beam with space charge in isochronous accelerators

Zhang

Tang

et al. 2010

Journal of Applied Physics

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“…The extraction trajectory can be calculated by integrating Eq. ( 1)- (3). Assume the beam transport is linear here, for the paraxial particles we have:…”

Section: Methods To Calculate Extraction Trajectories and Transfer Ma...mentioning

confidence: 99%

“…The stripping points with various energies have been calculated with the code CYCTR [2] and checked by the codes GOBLIN [3] and Strip-ubc seperately.…”

Section: Introductionmentioning

confidence: 99%

Stripping extraction calculation and simulation for CYCIAE-100

Guan

Xie

et al. 2009

Chinese Phys. C

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A 100 MeV H- compact cyclotron is under construction at China Institute of Atomic Energy (CYCIAE-100). The proton beams of 75 MeV-100 MeV at an intensity of 200 μA will be extracted in dual opposite directions by charge exchange stripping devices. The crossing point at the switching magnet center is fixed inside the magnet yoke and the stripping points for various extraction energies are calculated by the code CYCTRS. With the code GOBLIN, we can calculate the transfer matrix including the dispersion effects from the stripping point to the switch magnet. The beam distribution just after stripping foil can be obtained from the multi-particle tracking code COMA and the extracted beam parameters after the switch magnet such as emittance, envelope, dispersion, energy spread, bunch length, etc. are given by the extraction orbit simulations.

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“…Poles misalignment will cause the magnetic imperfection. The emittance growth caused by the imperfection magnetic fields, especially the field components B r on the mid-plane and the 1st harmonic of vertical field, will be analyzed in detail with tracking code COMA [2] . According to the simulation results, the tolerance of the poles machining and assembly will be illustrated in this paper.…”

Section: Introductionmentioning

confidence: 99%