1. Els de Wolf, Nikhef/UvA KM3NeT WP345-meeting 23 February 2009
The SeaWiet project SEnsor Architecture for a WIde Energy range Telescope
Els de Wolf, Nikhef/UvA
KM3NeT WP345-meeting
23 February 2009

2. Outline KM3NeT DS objectives and constraints Companies consulted
Starting points in 2006 for design
Choices made:
- Site
- Physics
Detector geometry
Budget constraints
- OM
- Storey
Detection Unit
DU deployment method
Readout/DAQ

3. KM3NeT DS objective and constraints
Design a facility with a cubic kilometre scale telescope in the Mediterranean Sea to detect neutrinos from point sources, GRBs, DM,…. with a budget ~ 200 MEuro ESFRI: costs MEuro

4. Companies consulted PMT Photonis (30 PMTs for free, bought about 80)
DU e/o cable
Sea Proof Solutions
Seacon (bought reference DU e/o cable)
TKF
JDR (also MEOC) (order feasibility study?) OM
Nautilus (bought spheres)
Optronics (ordered feasibility study application of coatings)
Readout DAQ
Van der Hoek Photonics (consultant photonic technology )
(TU/e), Cobra Institute
CIP Ltd (bought feasibility study and a reference model 10 Gb/s readout/DAQ)
Acreo
Corning (bought fibres)
Power system
PBF(order feasibiliy study?)

5. Starting points 2006 Site Single site, no preference for location
SeaWiet: design for 100 km
from shore, 5 km deep and
Antares-bioluminescence rates
and remote operation
Indonesia

6. Starting points in 2006 Physics
Broad energy range (DM – cosmogenic neutrinos), excellent angular resolution (CDR), largest possible effective area m
800m
1400 m
SeaWiet:
large ring with
- empty core
- ‘thickness’ ~ Antares
large height
OMs looking upwards
homogeneous distribution of OMs

7. Subject to change according simulation results
Geometry parameters
Simulation (WP2, Oct 2008)
Technical design (Nov 2007)
Hexagonal geometry
95 m between DUs
25 m between storeys (30)
21 storeys (20)
Total length DU 600 m (670)
154 DUs
Volume < 1 km^3
Not a fixed geometry
95 m between DUs
25 m between storeys
21 storeys
Total length DU 600 m
300 DUs
Volume > 1 km^3
Subject to change according simulation results

8. Starting points in 2006 Budget constraints SeaWiet: optimise
Build a detector with the largest effective area for the specified amount of money ( MEu)
SeaWiet: optimise
cost of storey
# sea operations
ANTARES
KM3NeT
Total costs
25 M€ M€
#total storeys
300
6300
Cost per storey)*
83 k€
40 k€
Factor ~2 cheaper
)* incl. R&D and sea operations

9. Starting points in 2006 Storey SeaWiet: OM=Storey multiPMT OM
Photocathode area ~ amount of an Antares storey
Excellent two photon separation (random background rejection)
Looking upwards (atm. muon background rejection)
Simple mechanical structure
No separate electronics container
(No separate instrumentation container)
physics
money
SeaWiet:
OM=Storey
multiPMT OM

10. OM parameters 10 stage Photonis, Concave front
Bialkali cathode, Q.E. 42%
31 PMTs (3”) in 17” glass sphere
19 in lower hemisphere
12 in upper hemisphere
PMT base < 30 mW
Request Erlangen to investigate with other PMT manufacturers

11. Design OM=Storey

12. OM assembly
31 x 3” PMTs
Low power base (< 30 mW)

13. Status OM (talk Eric Heine in WP3 session)
Test with PMTs in lower hemisphere in dark water basin with K40 (just started)
PMT base being further optimised
1st mechanical reference model finished
Assembly procedure
Cooling test
2nd mechanical reference model being prepared
Further optimisation
Verification of assembly model for production

14. Storey parameters Storey electronics included in glass sphere
(talk of Jelle Hogenbirk in WP4 session)
Room for acoustic detectors, tilt meters, compasses inside glass sphere
Mechanical structure is a ‘ring’ of composite material attached to two parallel aramide ropes in de DU mechanical structure
(talk of Eric Heine in WP5 session)

15. Starting points in 2006 DU (String concept)
Minimise # pressure transitions
Ready-to-deploy assembly method
Compact deployment
No maintenance
SeaWiet: oil filled flexible e/o cable, equi-pressure operation, break-out-box per storey, pressure transition at OM and at SJB only

16. Details being worked out together with NIOZ
DU layout
Oil filled e/o cable (OD ~10 mm)
21 fibres, 2 copper wires
2 parallel aramide ropes (OD ~4 mm)
Details being worked out together with NIOZ
Breakout-box
Master Module (DWDM) (operation in oil under pressure, being investigated)
e/o interlink cable to SJB (2 fibres)

17. DU e/o cable reference model
3 break-outs
40 fibres, interlinked (400 m)
6 copper wires
2 fibres+2 wires at each break-out
Manufactured by Seacon

18. Pressure test at NIOZ 40 fibers interlinked (400 m)
Large connector broke at 300 bar
Fibres performed as expected

19. Status DU e/o cable Reference model tested at 1 atm: OK
In pressure tank at NIOZ:
Part of the large 40 fibre connector broke at 300 bar
Fibres performed as expected
Next steps
Meeting with Seacon in March
Adapt cable closer to foreseen design
Remove 40 fibre connector
Repeat pressure test (600 bar)

20. Parameters DU e/o cable
Oil filled flexible hose
OD ~10 mm
21 fibers, one for each storey
2 conductive copper wires
Break-out-box with fuses at each storey (failure of storey should not propagate)
Either connector in BOB or splice during assembly (under investigation)

21. DU deployment method Need for experts ANTARES KM3NeT #lines 12 300
Deployment period
2 year
4 year
#deployments/yr 6 75
Factor ~13 faster
)* incl. R&D and Sea operations
Need for experts

22. Status DU deployment method (talk Eric Heine in WP5 session)
NIOZ involved in development since Jan 2009
Compact deployment
Simultaneous deployment of many DUs
DUs may be interconnected into a sector before deployment
Optimisation studies started
NIOZ plans tests in 30 m height water basin

23. Starting points in 2006 Readout/DAQ
All-data-to-shore concept (GRBs, flexible triggering)
Sensor concept: small # active components off-shore (readout is equivalence of lemo-cable)
Point-to-point optical connection shore-OM
SeaWiet: 10 Gb/s fibre technology, built in timing calibration, front-end electronics on shore

24. 10 Gb/s data transmission
Sub-sea station (DWDM+modulator)
Fiber to shore
100 km
(ms signal propagation)
Shore station
(CW-laser)
SPARK, DAQ reference model built by CIP Ltd

25. 10 Gb/s data transmission
Requirement achieved:
rigid timing
(<10 ps)

26. Read/DAQ architecture (talk Jelle Hogenbirk in WP4 session)
Timing calibration similar to Antares system:
Laser on-shore
Light pulse reflected at each OM
Time-stamp added on-shore
No separate fibre+electronics off shore
On shore
-Ethernet access to each OM/Storey
Off-shore
PMT data collection
Integrated Timing and Trigger Control
Slow Control enables
Ethernet based
bi-directional data transfer

27. Status Readout/DAQ (talk Jelle Hogenbirk in WP4 session)
SPARK, reference model built by CIP Ltd
Shore station + Subsea station (DWDM+modulator)
Result: rigid timing (< 1 ps) over 100 km
10 Gb/s technology is feasible for KM3NeT architecture
Node Development Kit under construction
For development of node interface configuration (OM, instrumentation, …)
Storey logic inside OM can be considered to be controlled by single Ethernet node which is physically on-shore
Logical layer is provided between primary OM functions and the Ethernet node

28. Summary Site: single site, no preference
Physics: aim for wide energy range
Detector geometry: simulations needed
Budget constraints: largest volume for MEu
Storey=OM
Configuration of 31 PMTs (3”) fixed
Low power PMT base is according specs, further optimised
1st mech. ref. finished: cooling according specs
2nd mech. ref. model: verify assembly planning
K40 measurements with PMTs in hemisphere just started

29. Summary DU DU deployment method
Equi-pressure operated e/o cable with break-out-boxes
Cable to be adapted and pressure tested again
Operation of DWDM under pressure under investigation
Mechanical design together with NIOZ
DU deployment method
NIOZ involved
Compact deployment
Tests planned in 30 m height water basin

30. Summary Conclusion: design well on its way, no show stoppers
Readout/DAQ
10 Gb/s technology proven
Rigid timing (< 1 ps over 100 km) shown (SPARK)
Node Development Kit under construction
Conclusion:
design well on its way, no show stoppers