Lower divertor cryopump
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pros:

generally high pressure in lower divertor
usable LSN operation
high heat load capability
should be able to fit 6 to 7: 6000 - 7000 l/s
may be faster to fabricate and install hardware (Oct 1st)
we have demonstrated operation of this type of pump with the prototype

cons:

new hardware in very crowded area of machine
pump will have to be removed to work on outer divertor
may not be compatible with the advanced divertor
not sure yet that we can feed 7 pump modules in series (probably can)
can we get into h-mode with pump on


Upper divertor cryopump
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pros:

simple, elegant pump design
good pumping speed (12000 to 15000 l/s)
should be very good at reducing h/d


cons:

considerably lower pressure even in near double null configuration
may not be very useful during the majority of our operation (LSL)
lower heat load capability
design and fabricate new upper divertor hardware makes Oct 1st unlikely
slotted design provides many new edges