10 October 2023 – An important two-week marine operation has been successfully carried out at the KM3NeT ARCA site, offshore Capo Passero, Sicily in September.
The campaign was performed with the Optimus Prime, equipped with a FUGRO underwater vehicle (ROV). The ship set sail from Malta on Monday, 11 September and came back to the port at the end of the operation on Thursday, 23 September.
The operation was among the last activities of PACK, a project supported by MUR (the Italian Ministry of University and Research) for the period 2019-2023, aimed at enlarging the deep-sea telescope and at enhancing the KM3NeT facilities in Bari, Caserta and Naples.
Soon after completing the operation, the commissioning of the enlarged ARCA telescope was started.
ARCA now comprises 28 detection units, which are altogether equipped with 504 Digital Optical Modules, with a total of more than 15,000 photomultipliers.
Deployment of a detection unit from Optimus PrimeThe start of the unfurling of a detection unit as seen from the ROV control room onboard the Optimus Prime.Tests of a newly deployed detection unit from the shore station in Portopalo di Capo Passero
22 November 2022 – After 4 years of activities carried out by the Italian funding agency INFN and Alcatel Submarine Networks, part of Nokia, the new subsea network for KM3NeT ARCA, funded under the Idmar regional project in Italy, is now complete.
The new system comprises a 100 km long electro-optical cable, equipped with 48 optical fibres for detector control and data communication and two electrical conductors for power distribution, connected to the shore station control and power feeding equipment, that can deliver up to 80 kW offshore. The cable is bifurcated in order to serve the two building blocks foreseen in ARCA.
During a 10 days long sea operation, which ended on November 17th, a cable termination frame (CTF) was installed on the northern branch of the cable. To this purpose the end of the cable, which was deployed already in 2020, was recovered from the sea floor and connected to the CTF onboard the deployment ship – the Ile d’Ouessant of Alcatel Submarine Networks. Then the CTF was carefully deployed to the target position on the sea floor. Extensive tests were done before and after the deployment to ensure its nominal behaviour.
The CTF is a large-size, 12-ton component which is equipped with four medium voltage converters and a total of 16 electrical and optical subsea connectors for connecting a set of submarine junction boxes to which the detection units will be in turn connected.
With this installation the connectivity and power transmission capabilities of the network have been increased by a factor four compared to the first part of the network, used to run the set of junction boxes and the first 30 detection units of ARCA Phase 1. This will allow for the completion of the construction of the first building block of ARCA and prepares the field for the installation of a second CTF on the other branch of the cable for the second building block.
The CTF at the end of the integration.CTF onboard Ile d’Ouessant.Overboarding of the CTF.
12 September 2022 – New sea campaigns were performed last week for both ARCA and ORCA. The purpose was to prepare the field for next installation phases of the detectors as well as to deploy new detection units and acoustic beacons – the latter are autonomous calibration devices which run on batteries and need to be replaced after some time.
The number of detection units in operation in the deep sea has been increased to 32 (comprising almost 18,000 photomultipliers): 21 in ARCA and 11 in ORCA.
After installation of a third junction box at the ARCA site, this site is now fully equipped for hosting the so-called Phase-1 of the project, comprising the first 31 detection units and the calibration unit of the apparatus.
The ARCA sea campaign represented the final action of the IDMAR project in Italy, supported by Regione Sicilia.
These operations were made possible by the dedication of hardware teams and the onshore and offshore teams at the two sites – the Collaboration is very grateful to them.
The newly added junction box of ARCA on the sea bottom.Detection unit deployment at the ORCA site.
14 June 2022 – The sea campaign for enlarging the KM3NeT/ARCA submarine telescope has been completed with full success!
During the last few days, all detection units loaded on Handin Tide for the second phase of the operation were carefully installed on the sea bottom. This was achieved at a record-breaking speed, with 7 detection units installed, connected and unfurled in less than 48 hours!
As a result of the campaign, the size of ARCA has more than doubled. It now comprises 19 detection units in operation, equipped with more than 10,000 photomultipliers,
We thank the teams which worked tirelessly offshore and onshore to reach this remarkable success. And we can’t forget that this was made possible by the hard work ongoing in the almost 30 integration sites of the Collaboration.
The activities at sea went around the clock during the campaign.
The shore station during the campaign – more than 30 people were involved in the onshore team for this campaign.
11 June 2022 – Due to the adverse weather conditions of the last days, the schedule of the sea campaign had to be redefined.
Here is the updated plan:
the ship left Malta this afternoon, to be back at the ARCA site tonight
the deep sea activities will be started already during the night
DU deployments will be started tomorrow
end of the operation is foreseen for early next week
Good luck to our offshore and onshore teams!
Empty LOMs (the launcher vehicles used for deployment and unfurling of the detection units) on the dock in the Malta port after the first phase of the sea campaign.The deck of the Handin Tide loaded with detection units and their cable trays for the second phase of the campaign.The Handin Tide leaving the port of Malta this afternoon.
6 June 2022 – The first round of activities of the ongoing sea campaign at ARCA has been completed.
In a summary, in the past week-end:
we installed two submarine junction boxes, one of which in replacement of the temporary junction box that we have used so far
the temporary junction box has been safely recovered
we moved all connections of the detection units already installed on the sea bed onto the new junction boxes
we installed 4 new detection units (where, by installation, one should understand that each detection unit was lowered to the bottom of the sea, carefully placed on the sea bottom, connected to the junction box and unfurled to reach its nominal, upright configuration)
Each of the steps above comprised dedicated tests, requiring careful coordination of the activities of the onshore and offshore teams.
And… the campaign is not yet finished! The ship is now heading back to Malta to load an additional set of detection units to install.
Stay tuned, as there will be more to report in the next days!
Preparation to deployment of the first detection unit to be installed during the campaign. On the right of it is one of the junction boxes awaiting installation, on the left the temporary junction box recovered from the sea floor.
The first detection unit installed in this campaign gracefully splashes into the water, to start its journey down to 3,500 m depth.
3 June 2022 – A new sea operation was started yesterday aiming at a significant enlargement of the ARCA neutrino telescope.
This is a major step forward for the Collaboration, as this is the first time ever that we launch a 2-weeks campaign. The scope of the operation in fact is twofold: upgrade the submarine network, by installing 2 brand-new junction boxes in replacement of the junction box that we have been operating so far, and to install new detection units (DUs). The operation will therefore take place in two steps: after the first round of activities for installation of the junction boxes and the first 4 DUs, the ship will come back to shore to pick up an additional set of DUs.
Handin Tide, which has already performed the previous sea campaign for KM3NeT ARCA last year, is the ship which will conduct this operation.
The ship left the port of Malta yesterday afternoon.
Remain connected, as we will be posting news about the operation while the action goes on – on our blog and on our social channels.
A set of KM3NeT DUs ready for deployment in the port of Malta earlier this week.
Loading of a KM3NeT DU onto the Handin Tide.
The Handin Tide sailing off from Malta in the afternoon of yesterday, June 2.
15 September 2021 – after the recovery of two old detection units, already left disconnected after previous sea campaigns – the so-called PPM-DU (Pre-Production Model of Detection Unit), a 3-digital optical module unit used for qualification of the project in the sea as early as in 2014, and one of the first prototype full-size detection units deployed in spring 2016, the sea campaign of ARCA has been completed today.
A lot of good work has been done in this intense week – and we are very grateful for that to the onshore and offshore teams. We also thank all the various institutes which contributed to the construction and preparation to deployment of the detection units – in next entries on this blog we will report on these demanding activities.
As a summary, during this sea campaign:
the positioning system has been maintained by installing two acoustic beacons and recovering an exhausted one (these are autonomous devices running on batteries which need to be refurbished in due time)
five interlink cables were installed on the sea bottom
three new detection units were installed, i.e.: deployed to the sea bottom, connected to the submarine infrastructure, unfurled to their nominal shape (standing for almost 700 m above the sea floor) and proved to work
the launcher vehicles of the three installed detection units and the cable trays used for deploying the cables were of course recovered, to be reused for next campaigns
After completing this set of operations, Handin Tide safely sailed back to the port of Malta.
Note that it was decided not to install the remaining two detection units which were onboard the ship, due to a mechanical issue that will be solved. These two detection units have been taken back to shore. After adequate refurbishment, they will be added to those already in preparation. Nothing is lost therefore: they will be included in the next sea campaign.
In the end… it’s time to resume detector operation of ARCA now!
The KM3NeT Collaboration is very grateful to the onshore (in the picture) and offshore teams for their hard work, instrumental for the success of this sea campaign – note that the full operation was performed respecting all applicable rules against COVID-19: our onshore team got so close together only for the time of a… “cheese”!
14 September 2021 – the ARCA telescope is now enlarged with 3 new detection units.
The procedure for installing a detection unit in ARCA is as follows: firstly the detection unit is lowered from the deck of the ship. When it reaches a low level above the sea floor, the ROV (the submarine vehicle operated from the ship) comes in play: it takes a bridle and helps to guide the detection unit to its target position on the sea bottom; it also rotates it so that the panel for connection of the submarine cable faces the direction of the submarine junction box. Only at that point, the detection unit is lowered on the sea floor. After a quick visual check, the ROV detaches the deployment line. The ROV then picks up the cable which had been previously routed on the sea bottom and which is connected to the junction box on the opposite end, and plugs it to the detection unit. Then the onshore team is asked to perform a first round of test to ensure that the detection unit meets its functional requirements. After that, the ROV opens a release mechanism that lets the deployment vehicle on which the detection unit is furled free to go. The vehicle is buoyant and starts coming up; while doing so, it rotates, leaving the detection unit, which is tied to the anchor on the sea floor, upright – a sort of giant, and reversed yo-yo!
After unfurling, the deployment vehicle is recovered from the ship, to be reused for next deployments.
A final test of the newly installed and unfurled detection unit is then performed to confirm that the detection unit works as expected.
This happened three times today!
An optical spectrum analyzer is used in the shore station for a check of the quality of the communications with the detection unit (almost 100 km away, 3,500 m deep). Each signal (in the form of a peak) in the plot corresponds to one of the optical modules of the detection unit. Believe it: when this plot appears on the screen of the instrument, it is a fantastic reward for all the hard work done in the sea campaign and before!
13 September 2021 – Still a day packed of activities today!
The status at the moment is that all interlink cables have been layed down on the sea floor and two detection units have been deployed and connected to the junction box. The detection units are still furled on their launcher vehicles; they will be allowed to unfurl tomorrow – since the launcher vehicle has to be recovered from the ship after it reaches the surface, it is better to perform this operation in the daylight.
Pre-unfurling functional tests performed from the onshore control station show that those first two detection units are in good order.
Deployments of the next detection units will continue during the night.
The onshore team in the control station at Portopalo di Capo Passero, Sicily, Italy.
