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Particles
The program calculates the particle rate using a formula developed
by Steve Snowdon et al (Ap.J. 393,819 (1992)) and Pluchinsky et al
(Ap.J. 418,519 (1993)). There are three particle components;
external particles, internal detector noise and florescent Aluminium
X-rays produced within the spacecraft. Each of these components have
different temporal, spectral and positional dependencies, but can be
modelled accurately as a function of a single parameter. This parameter
is the Master veto rate, which is recorded as a function of time in the
eventrate file which comes with each observation. This is only
really important for background subtraction of extended sources.
The program outputs the fraction of the background counts which are
particles. This should be about 1-2% for open observations and
around 4% for observations taken with the boron filter.
To create a file containing the particles in the BACKGROUND box
(not the source box), put PART_FILE=filename on
the command line.
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