Re: Cinder Blocks

[tdc@ehssun.lbl.gov (Ted M. de Castro)]

>>Does anyone know a good reference listing the lead equivalency of hollow
>>cinder blocks at various energies? A simple measurement shows the hollow
>>portion, about 2.5 inches of cinder block (this ain't no 147 lb/ft3), to
>>be about one HVL at 662 keV. At 420 or 350 kVp, one HVL would probably
>>be very conservative.

I've done this before .....

Just weigh the block and then assess its volume via calculation or 
displacement.  To assess via displacment be SURE to seal it first so it 
doesn't absorb the water.

THEN to be conservative - ignore the center partition thus assuming a 
completely hollow block and using the density just determined calculated the 
attenuation as if it were concrete.

Actually for the energies mentioned - I'd not consider hollow block!  Filled 
block at least.  Even then additional shielding would most likely be 
necessary.