Fiducial Cuts for the CLAS E5 Data Set

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Fiducial Cuts for the CLAS E5 Data Set K.
Greenholt (G.P. Gilfoyle) Department of Physics
University of Richmond, Virginia
Most of the fits we made were high quality, but
a few required intervention. Here we discuss how
we identified and fixed those fits.
s1_p08_plot44
s6_p08_plot34
s5_p08_plot35
What is Acceptance?
CLAS CLAS is located in Hall B and is used to
detect pions, electrons, protons and other
subatomic particles. The detector is able to
detect most particles created in a nuclear
reaction, because of its unique
nearly-full-solid-angle structure. There are six
different layers of CLAS see Fig. 2 which
produce electrical signals, providing us with
information on velocity, momentum, and energy,
and allow us to identify different subatomic
particles. The drift chambers make up the
first three layers, and determine the paths of
different particles. The next layer is the
Cerenkov counters which separate electrons from
pions. The following layer is made of the time
of flight scintillators to determine time of
flight and hence velocity. The calorimeters, used
to measure the energy of the particles, make up
the final layer. Also in CLAS is a toroidal
magnet that causes charged particles to bend as
they pass through the drift chambers. This
bending is used to determine momentum. This
magnetic interaction is of particular interest to
us, as we attempt to define the fiducial volume
of the detector, because it affects the regions
of stable efficiency.
Where do we Start?
Upper Edges
Upper Edges
Lower Edges
Lower Edges
References 'Fiducial Cuts for electrons in the
CLAS/E2 data at 4.4 GeV', D. Protopopescu, F. W.
Hersman, M. Holtrop, UNH, S. Stepanyan, CNU, and
CLAS/E2 run group, CLAS-Note 2000-007, November
27, 2000.