  Measurements of cosmogenic particles at various locations and altitudes are
becoming increasingly important in view of worldwide interests in rare signals
for search of new physics. In this work, we report measurement of muon zenith
angle distributions and integrated flux using a portable setup of four
one-meter long liquid scintillator bars. Each scintillator bar is read out from
both sides via photomultiplier tubes followed by an 8-channel Digitizer. We
exploit energy deposition and excellent timing of scintillators to construct
two dimensional tracks and hence angles of charged particles. We use liquid
scintillators since they have an added advantage of pulse shape discrimination
(PSD) which can be used for detecting muon induced particles. The energy
deposition, time window of event and PSD cuts are used to reduce the random as
well as correlated backgrounds. In addition, we propose three track quality
parameters which are applied to obtain a clean muon spectrum. The zenith angle
measurement is performed upto $60^\circ$. With our improved analysis, we
demonstrate that a setup of 3 bars can also be used for quicker and precise
measurements. The vertical muon flux measured is $66.70 \pm 0.36 \pm 1.50$
$/m^2/sr/s$ with $n=2.10 \pm 0.05 \pm 0.25 $ in $\cos^n \theta$ at the location
of Mumbai, India ($19^{\circ}$N, $72.9^{\circ}$E) at Sea level with a muon
momentum above $255$ MeV/$c$. The muon flux has dependence on various factors,
the most prominents are latitudes, altitudes and momentum cut of muon so that
portable setup like this can be a boon for such measurements at various
locations.
