Library of Congress Cataloging-in-Publication Data Karzmark, C. J. Medical electron accelerators 1 C.J. Karzmark, Craig S. Nunan, and Eiji Tanabe. p. cm. : Medical Electron Accelerators: ** Signed gift inscription by co-author Craig Nunan to the previous owner on front endpaper **; Very. Medical Electron Accelerators by Karzmark, C. J.; Nunan, Craig S.; Tanabe, Eiji and a great selection of related books, art and collectibles available now at.
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In the proposed configuration, the megavoltage electric field at the cathode is constantly changing as the electric field oscillates back and forth. We have made minimal effort to optimize the RF structure for a temperature-limited cathode—for instance, further optimization of the radial focusing fields around the cathode could be undertaken, and the spatial energy distribution at the target could be optimized by lowering the fields in the first half cavity.
This distortion can be corrected up to a point, as evidenced by current first generation MRI-Linac systems which successfully utilize magnetic shielding for either the electron gun or the entire Linac. Radiofrequency field calculation The next step was to calculate the RF fields to which the electrons will be subject while in the accelerating structure.
Computational simulations suggest that replacing conventional DC electron sources with a RF based source could be used to develop medical electron accelerators which are robust to operation in in-line magnetic fields. Exactly the same geometry as in Sec. English View all editions and formats. Computer programs for calculating stopping-power and range tables for electrons, protons, and helium ions,p.
In reality, perfect alignment is not possible. Accelerwtors this will impact penumbral width, it is expected to have minimal impact on clinical dose distributions, as a number of studies have found that the radiation dose is quite insensitive to the spot size. RF guns are widely used in other particle accelerator fields, electrom instance, as injectors to synchrotron beams. Further details on this method can be found in Ref. It can be seen that whilst the median energy and current are barely changed by the addition of in-line fields, the spot size and interquartile range undergo large deviations compared to the zero field values.
Medical electron accelerators.
Citations are based on reference standards. Don’t have an account? Would karzmadk also like to submit a review for this item? For each step, the beam assessment was repeated. Model of thermionic emission In conventional medical DC electron guns, a relatively low kilovoltage electrostatic field is applied to a thermionic cathode, resulting in space charge limited thermionic emission the space charge of the beam limits the emitted current.
A large amount of strategies to mitigate karzmarj back-bombardment effect in RF guns has already been published, and given that there is already at least one system in existence operating at similar pulse lengths and energies as would be required for this system the Kyoto University free electron laser injectorit is reasonable to believe that this effect could be managed.
The resultant electromagnetic coupling of the two devices results in many engineering and design challenges, one of which is the production of an acceptable treatment beam—the subject of this paper. The geometric emittance is 0. As such, there are only two changes to the initial geometry published by St. However, the spot size ranges from 0.
On the other hand, if the dose per pulse remains consistent i. Support Center Support Center. Aubin and found to be small even for exaggerated acceleratoors.
However, this work accelreators intended as a proof of principle, and the explicit modeling of an input power port is not anticipated to significantly affect the results. Please verify that you are not a robot. Particle tracking was carried out over a time period of ps, representing around six RF cycles and two full electron bunches at the target plane. You already recently rated this item. Please enter your name. Beam assessment at the target In order to assess the performance of the RF gun based accelerator, a beam monitor was placed at the exit of the simulation; accelerztors information was scored as it crossed this monitor and exported to matlab for further analysis.
The electric fields in the central region where the radial coordinate is less than 5 mm were sampled on a 0. Add a review and share your thoughts with other readers.
Medical electron accelerators. (Book, ) 
Please choose whether or not you want other users to elecyron able to see on your profile that this library is a favorite of yours. One interesting result is the large variations which occur in spot size as a result of in-line magnetic fields. Please re-enter recipient e-mail address es. The normalized emittance at the target was calculated using Eq.
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