6,769 research outputs found
Unrecognized Backscattering in Low Energy Beta Spectroscopy
We present studies on electron backscattering from the surface of plastic
scintillator beta detectors. By using a setup of two detectors coaxial with a
strong external magnetic field - one detector serving as primary detector, the
other as veto-detector to detect backscattering - we investigate amount and
spectrum of unrecognized backscattering, i.e. events where only one detector
recorded a trigger signal. The implications are important for low energy
particle physics experiments.Comment: 5 pages, 8 figures; v2: published NIM A versio
The point spread function of electrons in a magnetic field, and the decay of the free neutron
Experiments in nuclear and particle physics often use magnetic fields to
guide charged reaction products to a detector. Due to their gyration in the
guide field, the particles hit the detector within an area that can be
considerably larger than the diameter of the source where the particles are
produced. This blurring of the image of the particle source on the detector
surface is described by a suitable point spread function (PSF), which is
defined as the image of a point source. We derive simple analytical expressions
for such magnetic PSFs, valid for any angular distribution of the emitted
particles that can be developed in Legendre polynomials. We investigate this
rather general problem in the context of neutron beta decay spectrometers and
study the effect of limited detector size on measured neutron decay correlation
parameters. To our surprise, insufficient detector size does not affect much
the accuracy of such measurements, even for rather large radii of gyration.
This finding can considerably simplify the layout of the respective
spectrometers.Comment: 24 pages, 12 figure
Vector mesons in systems
A new selection rule is described for the vector mesons in the decuplet
representations of flavor SU(3)Comment: 7 pages and 1 figur
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