  The beta spectrum of the main transition of the beta-decay of 171Tm was
measured using a double focalizing spectrometer. The instrument was lately
improved in order to reduce its low energy threshold to 34 keV. We used the
spectrometer to measure the beta spectrum end-point energy of the main
transition of 171Tm decay using the Kurie plot formalism. We report a new value
of 97.60(38) keV, which is in agreement with previous measurements. In
addition, the spectrum shape was compared with the xi-approximation calculation
where the shape factor is equal to 1 and good agreement was found between the
theory and the measurement at the 1% level.
