ATLAS UPGRADE BARREL END SERVICES

1
ATLAS UPGRADE BARREL END SERVICES Work on
trying to reduce mass of cooling in R/PHI
Assuming cooling pipes have to be directed to
specific narrow channels on the cryostat and
cannot be spread around phi then layout must
include manifolding for cooling output on the
barrel end. This also reduces the considerable
mass. On the existing SCT barrel, there is one
cooling pipe per row of modules. On the upgrade
barrel, there will be two cooling pipes per
stave. Need to reduce numbers of pipes as close
to barrel as possible if you want to use EC
detectors! Otherwise you have an Iron Curtain
(well stainless steel probably) One way to do
this is could be to manifold pairs of pipes close
to the barrel end so that mass is reduced. The
number of pipes would then be closer to the
current SCT. To bring two cooling pipes of the
same type closer, to reduce mass of bridge,
alternate staves could be reversed with respect
to cooling pipe flow, so that stave at phi1
would have exhaust on left and input on right
(looking end on) and stave at Phi2 would have
exhaust on right and input on left etc. The
design of the short links could include strain
relief. Ongoing / Future work continue with
CAD drawings and excel spreadsheets. Lots of
possibilities to try out in order to reduce mass
at the barrel end but at the same time trying
not to increase the size of the envelope in Z.
TJ Fraser UCL 13.06.08
2
Upgrade Barrel end services (all layers)Total
Xo/side comparison
normal stave
reverse stave
3
Total Xo/side COMPARISON of UPGRADE with PRESENT
SCT BARREL COOLING at Barrel end Output and
Input pipes normal vs reverse stave
OUTPUT present SCT barrel spiders comparison
with 2 types of upgrade stave
INPUT present SCT barrel capillaries Comparison
with 2 types upgrade stave
Upgrade (3 layers short stave)
existing SCT
existing SCT
Upgrade (3 layers short stave)
normal cooling staves
normal cooling staves
Comparison with reverse cooling stave
Comparison with reverse cooling stave
Upgrade (3 layers short stave
Upgrade (3 layers short stave)
existing SCT
existing SCT
reverse cooling stave
reverse cooling stave
4
Total Xo/side for bus and cooling for Upgrade
all staves (3 short and 2 long) Comparison of
normal stave with reverse stave cooling, with
constant mass for bus.
bus
cooling normal stave
bus
cooling reverse stave
Note cooling assumed here to be CO2 with 3mm OD
cooling pipe on stave and with all cooling pipe
on barrel end stainless steel (for Upgrade). Opto
components not yet included.