1 May 2023 – During a two days sea operation, 27-28 April 2023, three detection units were successfully connected to the ORCA detector of KM3NeT in a record time of just over 24 hours. In addition, an acoustic beacon was recovered for battery replacement. The total number of deployed ORCA units is now 18, as visible in the sonar scan above.
As usual, the operation was performed with two ships: the Castor of Foselev, for deployment of the detection units, and the Janus II of SAAS (formerly Comex), equipped with a deep-sea remotely operated vehicle, for submarine operations.
Many thanks to the crews offshore as well as to the team who performed the functional tests of the new detection units from the shore station!
24 April 2023 – Following a successful sea operation, the 16-19 April 2023, a collection of new marine science instrumentation is now connected to the Laboratoire Sous-marin Provence Mediterranee (LSPM)) sea floor infrastructure at the KM3NeT/ORCA site, near Toulon, France.
During the three day sea operation the so-called ‘pre-SJB’, developed by CPPM Marseille, was connected into the seafloor network. The pre-SJB is a passive junction box housing an AC power transformer and a sea return electrode. During the same operation a remotely operated vehicle (ROV) connected an interlink cable between the pre-SJB and the previously deployed SJB.
The SJB (Scientific Junction Box), developed by Ifremer, is a junction box with six output dedicated to marine science instrumentation. The Pre-SJB/SJB are located about 3.7 km west of the main KM3NeT/ORCA detector. The SJB with its associated instrumentation had already been deployed about a year ago and was waiting for the pre-SJB installation to come online. An earlier incarnation of the SJB was previously installed on the ANTARES junction box.
The instrumentation currently connected to the SJB includes the BathyBot seafloor crawler, its docking station BathyDock (MIO/DT-INSU-Marseille) and BathyReef (an artificial reef), a broad-band seismograph (GeoAzur-Nice), a germanium gamma spectrometer (CPPM-Marseille,) and a stereo biocamera (IP2I-Lyon).
Two ships were involved in the sea operation: the Raymond Croze of Orange Marine and the Janus II of SAAS.
14 March 2023 – The KM3NeT Collaboration met online last week for the spring Collaboration meeting.
During the meeting we reviewed the status of data taking and data analysis of ARCA and ORCA, and discussed the progress in detector construction and the plans for next sea campaigns.
The Collaboration continues to grow: a research team has joined as full member of the Collaboration from University of Hull in UK (team leader: Brad Gibson) and a team from Ariel University in Israel (team leader: Dafne Guetta) has been welcomed as observer; furthermore, Marco Miceli of University of Palermo, Italy, has been accepted as associated member.
The plan for next Collaboration meetings was also finalized. A decision of the KM3NeT Collaboration, meant to reduce the carboon footprint on the planet, is that at least one of the general Colllaboration meetings is organized online per year. The next Collaboration meetings will take place in person, in early June in Salerno and in mid-October in Paris.
9 March 2023 – During the Spring KM3NeT collaboration meeting, the first-ever winners of the Giorgos Androulakis Prize were announced.
With the prize, KM3NeT recognises “exceptional contribution to the KM3NeT project that has a particularly high impact on the success or progress of KM3NeT”.
The prize is named after Giorgos Androulakis, the late KM3NeT Quality Manager, in order to commemorate Giorgos’ dedication to the project. The prize is awarded in two categories: Early-Career Scientists and Technicians & Engineers.
The winners of the KM3NeT Giorgos Androulakis Prize are:
in the category Early Career Scientists: Tamás Gál of ECAP, “for his prominent role and numerous contributions in the development and maintenance of essential software tools for the Collaboration, like the KM3NeT GitLab server, wiki, elog and online monitoring system, allowing the transformation of the KM3NeT software infrastructure into a modern software system; and for his continued dedication to provide documentation and support whenever needed in the most helpful way”
in the category Technicians and Engineers: Edward Berbee of Nikhef, “for his incredible set of contributions to all mechanical aspects of KM3NeT, including design, construction and testing of DOMs, DUs, LOMs, his never ending work and tireless dedication to the experiment”
Congratulations to Tamás and Edward! With many thanks for your dedication to KM3NeT.
The winners of the Giorgos Androulakis Prize: Tamás Gál (left) and Edward Berbee (right).
1 February 2023 – Via a long-distance electro-optical network the more than 6000 optical modules of KM3NeT in the deep sea are provided with a point-to-point connection to the control station on shore. The optical layer is presented in full details:
The optical data transport system of the KM3NeT neutrino telescope at the bottom of the Mediterranean Sea will provide more than 6000 optical modules in the detector arrays with a point-to-point optical connection to the control stations onshore. The ARCA and ORCA detectors of KM3NeT are being installed at a depth of about 3500 m and 2500 m, respectively and their distance to the control stations is about 100 kilometers and 40 kilometers. In particular, the two detectors are optimised for the detection of cosmic neutrinos with energies above about 1 TeV (ARCA) and for the detection of atmospheric neutrinos with energies in the range 1 GeV–1 TeV (ORCA). The expected maximum data rate is 200 Mbps per optical module. The implemented optical data transport system matches the layouts of the networks of electro-optical cables and junction boxes in the deep sea. For efficient use of the fibres in the system the technology of Dense Wavelength Division Multiplexing is applied. The performance of the optical system in terms of measured bit error rates, optical budget are presented. The next steps in the implementation of the system are also discussed.
12 December 2022 – During a sea campaign performed last week, ORCA has been enlarged by means of 4 new detection units. This brings the total of detection units deployed in ORCA to 15, comprising more than 7,500 photomultipliers.
The operation was performed with the Castor ship of Foselev, for deployment of the detection units, and with the Janus II of SAAS (formerly Comex), equipped with a deep-sea remotely operated vehicle, for submarine operations.
The KM3NeT Collaboration congratulates the crews on the two ships, the team who performed careful checks from the shore station during the campaign, and all the teams who contributed to the construction of the detection units, for the success of the operation.
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.
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 optical module of the KM3NeT neutrino telescope is an innovative multi-faceted large area photodetection module. It contains 31 three-inch photomultiplier tubes in a single 0.44 m diameter pressure-resistant glass sphere. The module is a sensory device also comprising calibration instruments and electronics for power, readout and data acquisition. It is capped with a breakout-box with electronics for connection to an electro-optical cable for power and long-distance communication to the onshore control station. The design of the module was qualified for the first time in the deep sea in 2013. Since then, the technology has been further improved to meet requirements of scalability, cost-effectiveness and high reliability. The module features a sub-nanosecond timing accuracy and a dynamic range allowing the measurement of a single photon up to a cascade of thousands of photons, suited for the measurement of the Cherenkov radiation induced in water by secondary particles from interactions of neutrinos with energies in the range of GeV to PeV. A distributed production model has been implemented for the delivery of more than 6000 modules in the coming few years with an average production rate of more than 100 modules per month. In this paper a review is presented of the design of the multi-PMT KM3NeT optical module with a proven effective background suppression and signal recognition and sensitivity to the incoming direction of photons.