128 research outputs found
Momentum Cogging at the Fermilab Booster
The Fermilab booster has an intensity upgrade plan called the Proton
Improvement plan (PIP). The flux throughput goal is 2E17 protons/hour which is
almost double the current operation at 1.1E17 protons/hour. The beam loss in
the machine is going to be an issue. The booster accelerates beam from 400 MeV
to 8GeV and extracts to The Main Injector (MI). Cogging is the process that
synchronizes the extraction kicker gap to the MI by changing radial position of
the beam during the cycle. The gap creation occurs at about 700MeV which is
6msec into the cycle. The variation of the revolution frequency from cycle to
cycle is larger at lower energy and it is hard to control by changing the
radial position because of aperture limitations. Momentum cogging is able to
move the gap creation earlier by using dipole correctors and radial position
feedback, and controlling the revolution frequency and radial position at the
same time. The new cogging is going to save energy loss and aperture. The
progress of the momentum cogging system development is going to be discussed in
this paper.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012, New Orleans, Louisian
Alignment and Aperture Scan at the Fermilab Booster
The Fermilab booster has an intensity upgrade plan called the Proton
Improvement plan (PIP). The flux throughput goal is 2E17 protons/hour, which is
almost double the current operation at 1.1E17 protons/hour. The beam loss in
the machine is going to be the source of issues. The booster accelerates beam
from 400 MeV to 8 GeV and extracts to the Main Injector. Several percent of the
beam is lost within 3 msec after the injection. The aperture at injection
energy was measured and compared with the survey data. The magnets are going to
be realigned in March 2012 in order to increase the aperture. The beam studies,
analysis of the scan and alignment data, and the result of the magnet moves
will be discussed in this paper.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012, New Orleans, Louisian
La relación isquiotibiales/cuadriceps como índice predictivo de gonartrosis
Se realiza un estudio muscular isocinético en grupo de 26 mujeres afectadas de gonartrosis, antes de la intervención, a los 6 meses y al año de la sustitución articular, realizando un estudio evolutivo y comparativo entre ambas rodillas con el objetivo de verificar si el balance muscular se altera paralelamente a la función articular y cual es su evolución tras la artroplastia. La rodilla artrósica presenta un cuádriceps más débil per conserva la función de la musculatura isquiotibial, con una relación isquiotibiales/cuádriceps aumentada patológicamente. Al año de la artroplastia no mejora la fuerza extensora, se conserva la fuerza flexora y se mantiene el balance muscular patológico. En la rodilla con menor afectación degenerativa la relación flexores/extensores se encuentra igualmente aumentada, por lo que se trata de su índice precoz de deterioro articular.An isokinetic muscular study was performed on a group of 26 women with primary gonarthrosis before surgery, six months and one year after joint replacement. An evaluative and comparative study of both knees was carried out in order to verify whether the muscular balance was altered in parallel with weaker but retained function of the ischiotibial musculature with an enhanced ischiotibial/quadriceps. One year after arthroplasty, extensor strength was not improved, though it was more efficient as revealed by reduced muscular fatigue, while flexor strength and pathological muscular balance were maintained. The flexor/extensor relation was also enhanced in the control knee, making this an early indicator of joint decoration
Transition crossing simulation at the Fermilab Booster
The demand in high intensity and low emittance of the beam extracted from the Booster requires a better control over the momentum spread growth and bunch length shortening at transition crossing, in order to prevent beam loss and coupled bunch instability. Since the transition crossing involves both longitudinal and transverse dynamics, the recently modified 3-D STRUCT code provides an opportunity to numerically investigate the different transition crossing schemes in the machine environment, and apply the results of simulation to minimize the beam loss and emittance growth operationally
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