  The alpha induced scintillation of the wavelength shifter
1,1,4,4-tetraphenyl-1,3-butadiene (TPB) was studied to improve the
understanding of possible surface alpha backgrounds in the DEAP dark matter
search experiment. We found that vacuum deposited thin TPB films emit 882
+/-210 photons per MeV under alpha particle excitation. The scintillation pulse
shape consists of a double exponential decay with lifetimes of 11 +/-5 ns and
275 +/-10ns.
