String mechanics and
production
P.Kooijman,NIKHEF/UU
Pylos, april 2007
How do we get signals out of sphere
• For readout to work need single optical channel connection between shore and OM
• Cable with 1 or 2 fibres per OM
• 2 copper per OM
• Need breakout at each OM
Solution being investigated
• Seacon equipresure “hose-cable”• Routinely used• Pressure insensitive fiber!!• Connectors and feedthroughs relatively cheap
Design is flexible (more ways)
• Only small area where pressure needs to be held
• Cable is a tube filled with oil and whatever you want (gets bigger with more content)
duct-hose
optical/electrical contact block
(vulcanized rubber)
fibrecopper
twisted pair inert oilany combination
So how do we use it
Thin structures filled with oil
Hose with 2 fibers and two coppers
Small hose connector
Pressure resistant connectorAnd bulkhead
hoseconnectors
Hose with many fibers
cable
What else?
• At bottom of line we need container for DWDM• After that can continue again with just 2 fibers• Much cheaper (less expensive solution) at
junction box
Wet mateable copper only (2)
Wet mateable fiber only (2)
Splitter equipressure
Hose connectors
Pressure feedthrough connector many fibers
DWDMJB
100mToOM
1km
Price?
• Dont know yet – but estimates come in at around k€ 11 for a floor with OM with 38 PMs including cable
• Only one end of interlink is wet mateable – no non-destructive recovery
• Split fiber and copper in wet mateable – lose very expensive connectors
• Sofar saving of about factor 2 per unit looks feasible
So how do we build 500 strings in 5 years?
• 5 sites
• 500 strings
• 5 years
20 strings/site/year (1/fortnight)20 strings/site/year (1/fortnight)
400 OMs/site/year (10/week)400 OMs/site/year (10/week)
16000 PMTs/site/year (400/week)16000 PMTs/site/year (400/week)
Delivery
• 2000 glass spheres per year
• 80000 PMTs per year
• 100 500m cables with connectors fibres etc per year
Delivery of tested entities
test report
PMT
PMTassembly
characterizestorage /transport
assembledPMT-base
OM assembly
characterize
connector
mechanics
central electronics
STRINGassembly
characterize
test report
test report
storage /transport
storage /transport
cable
mechanics
assembledbottom
instrumentation instrumentationinstrumentation
Assembly line
And of course
• Transport to the site
• Deployment at the site at rate of 2/week• Deploy in containers
• Maybe more “daisy-chained” together (6?? With just 1 underwater connection)
Conclusions
• Cable with breakout and connector to sphere – OM can be separately built and tested – complete system test because of single connection from shore to OM
• Cable looks to be possible with OM supports and breakouts
• First look at production looks tough but never say never
• Needs significant organisation and delivery streamlining
PS
500 strings = 200 M € = 40 Antares = 2km3
Where did we save/lose money
• 38 pmt (8kEuro) vs 4 10” (6kEuro) X20• 1sphere(0.5kEuro) vs 4spheres (2kEuro) X20• Modulator + SER+DES (2kEuro) vs (0) X20• No (0 kEuro) vs 1 Ti cylinder (10kEuro) X20• Connectors (1kEuro) vs (5kEuro) X20• No connection at stringbottom (15kEuro)X1• Connectors to JB (5kEuro) vs (15kEuro) X1