arXiv subjects

C. M. Bhat

Publications and source records attributed to C. M. Bhat.

22 records · Page 2Linked to original sources

arXiv2012

Transverse Instabilities in the FERMILAB Recycler

Transverse instabilities of the antiproton beam have been observed in the Recycler ring soon after its commissioning. After installation of transverse dampers, the threshold for the instability limit increased significantly but the instability is still found to limit the brightness of the antiprotons extracted from the Recycler for Tevatron shots. In this paper, we describe observations of the instabilities during the extraction process as well as during dedicated studies. The measured instability threshold phase density agrees with the prediction of the rigid beam model within a factor of 2. Also, we conclude that the instability threshold can be significantly lowered for a bunch contained in a narrow and shallow potential well due to effective exclusion of the longitudinal tails from Landau damping.

physics.acc-ph↗

arXiv2009

Longitudinal Stability of Recycler Bunches; Part I: Thresholds for Loss of Landau Damping

We examine the stability of intense flat bunches in barrier buckets used in the Recycler. We consider some common stationary distributions and show that they would be unstable against rigid dipole oscillations. We then discuss an analytical model for the line density that best describes measured bunch profiles. We include space charge in this model to predict the bunch intensity at which Landau damping would be lost. The dependence of this threshold on the bunch length is studied and related to the results of an experimental study with shorter bunch lengths. The threshold for the microwave instability is estimated. These studies will be followed by more detailed numerical studies.

physics.acc-ph↗

arXiv2004

Longitudinal Momentum Mining of Beam Particles in a Storage Ring

I describe a new scheme for selectively isolating high density low longitudinal emittance beam particles in a storage ring from the rest of the beam without emittance dilution. I discuss the general principle of the method, called longitudinal momentum mining, beam dynamics simulations and results of beam experiments. Multi-particle beam dynamics simulations applied to the Fermilab 8 GeV Recycler (a storage ring) convincingly validate the concepts and feasibility of the method, which I have demonstrated with beam experiments in the Recycler. The method presented here is the first of its kind.

physics.acc-ph↗

arXiv1998

A study of the solar neutrino survival probability

We present a study of recent solar neutrino data using a Bayesian method. Assuming that only $ν_e$ are observed in the Super-Kamiokande experiment our results show a marked supression of the survival probability at about 1 MeV, in good agreement with $χ^2$-based analyses. When the detection of $ν_μ$ by Super-Kamiokande is taken into account, assuming $ν_e$ to $ν_μ$ oscillations, we find the largest suppression in survival probability at about 8.5 MeV.

astro-ph↗