COLLECTION OPTICS WITH THE HORN TYPE FOCUCING ELMENT MADE WITH SEPARATE CONDUCTORS
We describe the device for focusing of charged particles by the system of separated conductors which follow the parabolic profile. Basically this is a horn-type focuser, but with the individual conductors instead of continuous surface. This device allows substantial reduction of fabrication cost with the same focusing properties as the continuous parabolic surface. We recommend this “bird-cage” type system for focusing pions/muons in the projects under discussion in many Laboratories around the World. OVERVIEW Necessity for good quality secondary beams is well argumented topic for the high energy physics [1]-[3]. The horn-like focusing elements (lenses) are broadly in use in many laboratories for collection of secondary particles in the proton lines. One example of usage of miniature copy of such lens for collection of positrons is known from Budker INP [4]. For collection of pions the horns reach sized of ~0.5 m in diameter and ~2 m long [5]. Fabrication of thin wall parabolic surface of this scale represents substantional technological difficulties. Typically it is fabricated from solid billets of 40-6061-T6 Aluminum with typical lengths of 40 cm [5]. Three segments are electron beam welded together. Typical thickness of the parabolic wall is around 2mm. In all horn-like focusing devises the secondary beams running through material of paraboloid. In this publication we made a proposition to approximate continuous surface of paraboloid with limited number of separate conductors. This approach delivers significant simplifications in technology of fabrication. The payoff for this-a distortions of trajectories can be made acceptable as the angular spread of secondary beams is significant. Any way it is comparable with divergences obtained as a result of multiple scattering in material of paraboloid.
NOvA Proposal to Build a 30 Kiloton Off-Axis Detector to Study Neutrino Oscillations in the Fermilab NuMI Beamline
This is an updated version of the NOvA proposal. The detector is a 30 kiloton tracking calorimeter, 15.7 m by 15.7 m by 132 m long, with alternating horizontal and vertical rectangular cells of liquid scintillator contained in PVC extrusion modules. Light from each 15.7 m long cell of liquid scintillator filled PVC is collected by a wavelength shifting fiber and routed to an avalanche photodiode pixel. The reach of NOvA for sin^2(2_theta_13) and related topics is increased relative to earlier versions of the proposal with the assumption of increased protons available from the Fermilab Main Injector following the end of Tevatron Collider operations in 2009.
A Monoenergetic Neutrino Beam Using Current-Sheet Focusing Elements
A monoenergetic neutrino beam has been designed using specially shaped horn-like focusing devices and selectively located meson absorbers. The advantages of this beam are its good energy resolution, its high flux for neutrino energies below ~100 GeV, its simple layout and its low stored energy.