  We present the first operation of the Avalanche Photodiode (APD) from
Hamamatsu to xenon scintillation light and to direct X-rays of 22.1 keV and 5.9
keV. A large non-linear response was observed for the direct X-ray detection.
At 415 V APD bias voltage it was of about 30 % for 22.1 keV and about 45 % for
5.9 keV. The quantum efficiency for 172 nm photons has been measured to be 69
+/- 15 %.
