Cs-137 Irradiator Radiation Exposure

[jerjr@holta.ho.lucent.com (John E Riley, Jr)]

We are planning to acquire a 300 Ci Shepherd irradiator--Model 81.  Can
anyone provide us with some guidance on expected exposure to the
operator from air scatter and wall reflections?
Conditions:
17x17 foot concrete room
horizontal 30 degree beam
source 12 feet from target wall
operator position 3 feet behind shielded side of source

Experience may be worth a lot of calculation here.

Thanks

Jack Riley
RSO
Bell Labs
Murray Hill, NJ