A

ΔE-E

plastic scintillator

β

telescope had been built

and calibrated by using a group of

β

-

and

β

+

emitters and a

207

Bi source. Their end-point energies were determined via two different methods

i. e. weighted linear least-square fit to the Fermi-Kurie plotes of the data after correcting for the finite energy resolution of the

E

scintillator and direct linear least-square fit to the square root of the raw data. It is shown that the latter can estimate the end-point energy rapidly

while the former can be used to determine the end-point energy with uncertainty about 35 keV for energy ranging 0.7 to 6.1 Me.