388 research outputs found
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Raising the acceptance of the AP2-line
The 120 GeV Main Ring proton beam collides with the target at the end of the AP-1 line and creates antiprotons and other secondary particles. The AP-2 line transfers the negative particles from the target to the Debuncher. To provide a bigger antiproton stack size in the Accumulator, both the Debuncher as well as the AP-2 line acceptance have to be raised. This is a proposal for the improvement of the AP-2 line acceptance. The first part of the memo presents an acceptance examination of the existing AP-2 line by computer simulation, while the second presents a short proposal for aperture corrections. The computer program TURTLE was used to trace antiprotons through the AP-2 line without taking into account other negative charged particles. Betatron functions were obtained from the output of the SYNCH computer program. The SYNCH program was also used to check the dispersion match between the AP-2 line and the Debuncher. 3 refs., 6 figs., 5 tabs
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Update on the Innovative Carbon/Proton Non-Scaling FFAG Isocentric gantries for Cancer Therapy
There is a dramatic increase in numbers of proton/carbon cancer therapy facilities in recent years due to a clear advantage with respect to the other radiation therapy treatments. Cost of the ion cancer therapy is still to high for most of the hospitals and a dominating part comes from the delivery systems. We had previously presented design of the carbon and proton isocentric gantries using the principle of the non-scaling alternating gradient fixed field magnets (NS-FFAG), where a size and weight of the magnets should be dramatically reduced. The weight of the transport elements of the carbon isocentric gantry is estimated to be 1.5 tons compared to the 130 tons a weight of the Heidelberg gantry. The similar claim of 500 kg comes for the transport elements of the proton permanent magnet gantry. We present an update on these designs
Animal Models in Peritoneal Dialysis
Over the last decades peritoneal dialysis (PD) has become a successful and widely used treatment for endstage renal disease patients worldwide. Together with the increasing number of uremic patients successfully treated with PD has grown an interest in physiological, pathophysiological and clinical aspects of this therapeutic method. This article provides an overview of the current status on animal models used in studying the histology and physiology of the peritoneum, as well as the process of peritoneal dialysis itself. We discuss species of experimental animals, methods of peritoneal access, sampling for histology, different techniques and methodologies, and complications of experimental models of PD.
Hadron cancer therapy complex employing non-scaling FFAG accelerator and fixed field gantry design
Non-scaling FFAG rings for cancer hadron therapy offer reduced physical aperture and large dynamic aperture as compared with scaling FFAGs. The variation of tune with energy implies the crossing of resonances during acceleration. Our design avoids intrinsic resonances, although imperfection resonances must be, and can be, crossed. We consider a system of three non-scaling FFAG rings for cancer therapy with 250 MeV protons and 400 MeV/u carbon ions. Hadrons are accelerated in a common RFQ and linear accelerator, and injected into the FFAG rings at .. .. . H+/C6+ ions are accelerated in the two smaller/larger rings to 31 and 250 MeV/68.8 and 400 MeV/u kinetic energy, respectively. The lattices consist of doublet cells with a straight section for RF cavities. The gantry with triplet cells accepts the whole required momentum range at fixed field. This unique design uses either high temperature super-conductors or super-conducting magnets reducing gantry size and weight. Elements with variable field at beginning and at end set the extracted beam at the correct position for a range of energies
Overcoming a fast transverse instability by means of octupole-induced tune spread in the Relativistic Heavy Ion Collider
During the Relativistic Heavy Ion Collider commissioning in 2001 a fast transverse instability was observed on the ramp. In general this could be counteracted with increased chromaticity, resulting in Landau damping. However this method could not be applied around transition energy where chromaticities have to change sign. So octupoles were used near transition energy to create transverse Landau damping and avoid the transverse instability, emittance blowup, and beam loss. This paper describes the considerations that led to the present scheme, as well as experimental results
Observation of experimental background in RHIC polarized proton run 2006
The beam-gas has affected STAR background in RHIC proton Run 2005, but not in Run 2006. With higher beam intensity in Run 2008, the beam-gas effect at STAR may be of concern. The ratio of ZDC background and coincident rate seems to be useful in proton runs in evaluating the experimental background
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