Problem of monitoring 15,000 channels within EPICS

[gaius@bnlku5.phy.bnl.gov (Chris Witzig)]

Hallo,

I am Chris Witzig and work for the Phenix experiment
at RHIC. We have the following problem to solve within
EPICS and are wondering whether some EPICS expert out
there knows an elegant (i.e. good and cheap) solution:

Our PbSc calorimeter has 15,000 PMTs. The HV is multiplexed
due to the high number of channels (1HV channel
is multiplexed to 48 PMTs). 
For monitoring/debugging purposes the PbSc group would like to 
monitor the current for every tube at the base.
The readback frequency is low (once every few minutes is
ok),  the accuracy doesn't need to be good  (less than 10 bit
good enough). Price is an issue of course.

Due to the high channel count we would like to
multiplex these 15,000 channels also for this monitoring
readback (1 EPICS readable scanning ADC is able to 
monitor several PMTs and EPICS is able to select which one).

Has anybody ever implemented such a system within EPICS?

Comments and suggestions are highly appreciated.

Best regards

Chris Witzig

email: witzig@bnl.gov