We report on the construction and upgrade of a Lawrence Berkeley National
Laboratory Cosmic Muons Detector. We modify the electronics and mechanics to
achieve a highly efficient gamma-ray and cosmic-ray detector. Each detector
module uses a one-inch-thick scintillator, attached to a photomultiplier tube
(PMT) and mounted on a solid aluminum frame. The detector uses scintillation to
transform passing radiation into detectable photons that are guided toward a
photocathode surface of the PMT, triggering the release of photoelectrons that
are then amplified to yield measurable electronic signals. The modules were
connected to an electronics section that compared the signals from the two PMTs
and logically determined if they were coincidence events. A data-collection
device was added for faster and prolonged count rates. A cobalt-60, which
produced two gamma rays and a beta particle has been used as a calibration
source. To investigate the isotropic behavior of radiation, two detection
modules were adjusted to different angles of rotation with respect to each
other, and the coincidence counts were measured. The coincidence counts from
the modules set at various angles were consistent throughout the angular
spectrum, and only lead shielding visibly reduced the number of counts from the
radioactive source. The inverse-square-law behavior of radiation has also been
considered. The results were such that the number of counts decreased as a
function of increasing distance from the source. Furthermore, positioning the
detector to point toward the sky in different orientations, we measured cosmic
ray muon flux as the angle from the vertical was decreased. In doing so, we
scanned different patches of the atmosphere. For the optimum operation during
the detection phase, we plateaued both PMTs to single out their best operating
gain voltage while eliminating false background noise signals
