2,593 research outputs found
Implications of a 20-Hz Booster cycle-rate for Slip-stacking
We examine the potential impacts to slip-stacking from a change of the
Booster cycle-rate from 15- to 20-Hz. We find that changing the Booster
cycle-rate to 20-Hz would greatly increase the slip-stacking bucket area, while
potentially requiring greater usage of the Recycler momentum aperture and
additional power dissipation in the RF cavities. In particular, the losses from
RF interference can be reduced by a factor of 4-10 (depending on Booster beam
longitudinal parameters). We discuss the aspect ratio and beam emittance
requirements for efficient slip-stacking in both cycle-rate cases. Using a
different injection scheme can eliminate the need for greater momentum aperture
in the Recycler.Comment: Fermilab Technical Memo 2587-AP
Integrable RCS as a proposed replacement for Fermilab Booster
Integrable optics is an innovation in particle accelerator design that
potentially enables a greater betatron tune spread and damps collective
instabilities. An integrable rapid-cycling synchrotron (RCS) would be an
effective replacement for the Fermilab Booster, as part of a plan to reach
multi-MW beam power at 120 GeV for the Fermilab high-energy neutrino program.
We provide an example integrable lattice with features of a modern RCS -
dispersion-free drifts, low momentum compaction factor, superperiodicity,
chromaticity correction, bounded beta functions, and separate-function magnets.Comment: arXiv admin note: substantial text overlap with arXiv:1703.0095
Comparing the orthogonal and homotopy functor calculi
Goodwillie's homotopy functor calculus constructs a Taylor tower of
approximations to F, often a functor from spaces to spaces. Weiss's orthogonal
calculus provides a Taylor tower for functors from vector spaces to spaces. In
particular, there is a Weiss tower associated to the functor which sends a
vector space V to F evaluated at the one-point compactification of V.
In this paper, we give a comparison of these two towers and show that when F
is analytic the towers agree up to weak equivalence. We include two main
applications, one of which gives as a corollary the convergence of the Weiss
Taylor tower of BO. We also lift the homotopy level tower comparison to a
commutative diagram of Quillen functors, relating model categories for
Goodwillie calculus and model categories for the orthogonal calculus.Comment: 28 pages, sequel to Capturing Goodwillie's Derivative,
arXiv:1406.042
Dynamical Stability of Slip-stacking Particles
We study the stability of particles in slip-stacking configuration, used to
nearly double proton beam intensity at Fermilab. We introduce universal area
factors to calculate the available phase space area for any set of beam
parameters without individual simulation. We find perturbative solutions for
stable particle trajectories. We establish Booster beam quality requirements to
achieve 97\% slip-stacking efficiency. We show that slip-stacking dynamics
directly correspond to the driven pendulum and to the system of two
standing-wave traps moving with respect to each other.Comment: Supplemental Material appended to pape
Wavefront error sensing
A two-step approach to wavefront sensing for the Large Deployable Reflector (LDR) was examined as part of an effort to define wavefront-sensing requirements and to determine particular areas for more detailed study. A Hartmann test for coarse alignment, particularly segment tilt, seems feasible if LDR can operate at 5 microns or less. The direct measurement of the point spread function in the diffraction limited region may be a way to determine piston error, but this can only be answered by a detailed software model of the optical system. The question of suitable astronomical sources for either test must also be addressed
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