  We present a deep Spitzer/IRAC survey of the OB association IC 1795 carried
out to investigate the evolution of protoplanetary disks in regions of massive
star formation. Combining Spitzer/IRAC data with Chandra/ACIS observations, we
find 289 cluster members. An additional 340 sources with an infrared excess,
but without X-ray counterpart, are classified as cluster member candidates.
Both surveys are complete down to stellar masses of about 1 Msun. We present
pre-main sequence isochrones computed for the first time in the Spitzer/IRAC
colors. The age of the cluster, determined via the location of the Class III
sources in the [3.6]-[4.5]/[3.6] color-magnitude diagram, is in the range of 3
- 5 Myr. As theoretically expected, we do not find any systematic variation in
the spatial distribution of disks within 0.6 pc of either O-type star in the
association. However, the disk fraction in IC 1795 does depend on the stellar
mass: sources with masses >2 Msun have a disk fraction of ~20%, while lower
mass objects (2-0.8 Msun) have a disk fraction of ~50%. This implies that disks
around massive stars have a shorter dissipation timescale.
