CTAO in Switzerland
Research groups
The University of Geneva is the leading house for CTAO in Switzerland
The DPNC – University of Geneva
The Département de Physique Nucléaire et Corpusculaire (DPNC) has Astroparticle as one of its 3 pillars, with high-energy particle physics and neutrinos. It has a long-standing tradition in building detectors, with outstanding workshops on electronics and mechanics specialised in silicon detectors that supported CTAO over time. The DPNC has designed and built the SST-1M telescopes, now taking data in stereo mode at the Ondřejov observatory. Its cameras were designed, developed and tested in the DPNC clean chamber. They implement advanced analog electronics for silicon photomultipliers (SiPM) that led to new ideas in the photo-sensing domain and medical applications. The DPNC has a longstanding program on cosmic ray physics from space with implementation and operation of well-known detectors in the field of direct CR measurements and dark matter, and astrophysical sources such as gamma-ray bursts. These are AMS, DAMPE, HERD, POLAR2 and now the prototype for Cherenkov detection from space TERZINA. The CTAO group at the DPNC, also involved in IceCube, SST-1M, LHAASO and MAGIC, has experience in hardware engineering and scientific data analysis. It is run by: Prof. Teresa Montaruli who joined the DPNC as Full. Professor in 2011 from UW- Madison, coordinating the CTAO-CH collaboration; Prof. Domenico della Volpe, project manager of the SST-1M and LST lead system engineer; MER Matthieu Heller leading the LST working group on the LST advanced camera. The DPNC is responsible for the calibration of the CTAO arrays and of the quality of their data.
The Astronomy Department – University of Geneva
The Extreme Universe group of the astronomy department of the University of Geneva started its activities in 1988. The group was selected by the European Space Agency in 1995 to build and operate the data centre of Europe’s gamma-ray space observatory INTEGRAL, in operation for more than 20 years. This included all activities from the decoding of spacecraft telemetry to the provision of high-level scientific products to the scientific community worldwide. The activities developed to support or lead other high-energy space missions such as POLAR, XRISM, POLAR-2, Athena and ground experiments such as FACT, MAGIC and CTAO. In parallel to their various operational duties, scientists are active in different research fields ranging from the study of various types of X-ray binaries, pulsars and their winds, massive stars and their winds, supernova remnant, active galactic nuclei, galaxy clusters, gamma-ray bursts and dark matter/cosmology using all types of astronomical facilities. On average, the group contributed to 50 referred papers per year. They led the first scientific paper based on data from the first CTAO telescope LST-1. The department is providing several in-kind contributions to CTAO: the software handling in real time the data of all CTAO
telescopes (about one million CD-ROMs per observing night), the control software for several CTAO
telescope types, the distributed data management system, archiving of the order of 10 PB of data per year. These efforts are led by Profs Roland Walter, Stephane Paltani and Dr Nicolas Produit.
Institute for Particle Physics and Astrophysics – ETH Zurich
The Institute for Particle Physics (recently merged with Astrophysics) has a long tradition of building and operating detectors at accelerators (e.g. CMS) as well as in space (e.g. AMS). In 2003, a group led by Prof. Felicitas Pauss and Adrian Biland joined the MAGIC collaboration to explore the highest energetic photons. The MAGIC telescope has a diameter of 17m and is able to point to any location in the sky within less than 30s. To achieve this, it is not built as a solid steel structure, but has a lightweight CFK frame. Nonetheless, the CFK frame deforms when pointing to different orientations, drastically reducing the optical quality of the instrument. Therefore, each of the 234 individual mirrors is equipped with an Active Mirror Control (AMC) to correct for this deformation. MAGIC was the first instrument equipped with AMCs, and in 2003 the performance was far from satisfactory. The ETH group took over responsibility and made the system work well within specifications. The group built an improved AMC for the second MAGIC telescope. Later, the UZH group took over the AMC for CTAO. When SiPMs became available, the group built within 4 years the first SiPM camera for the FACT telescope. In 2012, this success convinced CTAO to use similar sensors for the SSTs. Prof. Adrian Biland is active in MAGIC, FACT and CTAO in several positions since 2003, e.g. in MAGIC: convenor for fundamental physics (-2010), AMC coordinator (2004-), (Co-)chair of the collaboration board (2017-); in FACT: spokesperson (2007-); in CTA: board of working group convenors ( 2006-2012) , board of governmental representatives (2020-).
Department of Physics – University of Zurich
The Physik-Institut at UZH has a long history of detector development in particle and astroparticle physics. Specific to CTAO the main early involvement under Prof. U. Straumann was the development of FlashCam, a prototype camera for the MSTs, which was successfully tested in 2018 and it is now operating on the largest H.E.S.S. telescope leading to various breakthroughs. In particular, the group developed active control elements for automatic control of the mirror segments, as well as FPGA-based digital readouts of photon detection. Currently, the CTAO-related research activities are in Intensity Interferometry (led by Prof. Prasenjit Saha) and machine learning (led by Prof. Nicola Serra) for the Advanced Camera program. The research in Intensity Interferometry consists both of theory and simulations, and the development of new detectors. For the latter, the expertise developed earlier with FPGAs at UZH in the context of FlashCam is relevant. Prof. Saha was the coordinator of the stellar intensity interferometry working group of the CTA Consortium in 2022. In machine learning the primary focus lies in exploring the potential applications of deep learning, including their applicability to FPGAs. Nicole Serra’s group also holds a prominent position in LHCb, and is also actively involved in several notable projects, including SHiP, with Prof. Serra at the helm as the physics coordinator, along with SND@LHC and the Mu3e experiments. Prof. Serra's team showcases considerable experience in the realm of neural networks and is accountable for the Data Acquisition (DAQ) firmware of the UT.
Physics Department – University of Bern
The Physics Institute of the University of Bern has been active in space research since the 1960s and has led and helped develop >30 space experiments from Apollo 11 to the ROSETTA and CHEOPS missions. The institute has built structural elements for numerous ground and space experiments. In August 2021, Prof. M. Falanga was appointed Professor of High Energy Astrophysics at the University of Bern. With Prof. Falanga's commitment to UniBe, the CTAO is considered cross-disciplinary for the Physics Institute at the University, combining the Space Science Division and the High-Energy Physics Laboratory, which also deals with some aspects of particle astrophysics. Prof. Falanga has extensive experience in data reduction, analysis, and theoretical interpretation of compact objects in high-energy astrophysics. As a first step, Prof. M. Falanga, who recently became interested in CTAO, will be involved in the Data Quality Pipeline of DPPS. In the era of CTAO, when the detectors are extremely sophisticated devices and new physics is discovered, measurements of the quality of the recorded data guarantee not only solid and reproducible scientific results but also open the way to new discoveries. The scientific interest of the Bern group he is forming is related to the magnetosphere of a pulsar, the most extreme place in the universe due to their magnetic fields, plasma composition, emission of electromagnetic radiation and particle acceleration. The Bern group is interested in the mechanisms that allow pulsars to produce and accelerate gamma rays, aside from software building.
Advanced Quantum Architecture Laboratory – EPF Lausanne
The Advanced Quantum Architecture Laboratory (AQUA Lab) was founded in 2003 by Prof. Edoardo Charbon upon the premise of creating sensors capable of detecting single photons. As of mid-2023, the lab has graduated 33 PhD students and over 100 M.S. students in various disciplines, including electronics, CMOS and cryo-CMOS design, and photodetector and radio-frequency design. The lab holds several records: the highest timing accuracy in a SPAD (single-photon avalanche diode) at 7.5ps FWHM, the highest PDP (photon detection probability) in a CMOS SPAD at 78%, the smallest DCR (dark count rate) at 10mcps at cryogenic temperatures, and the smallest SPAD pitch at 2.2μm. The lab is responsible for many innovations, including the first deep-submicron SPAD in 2007, the first 3D- stacked SPAD camera in 2015, and the first megapixel SPAD camera. Many single-photon sensors came out of the lab, including the SwissSPAD family, capable of high dynamic range at high frame rates, the LinoSPAD family, for reconfigurable single-photon sensing, the Piccolo and Ocelot sensors, for TCSPC (time-correlated single-photon counting), and nanoSPAD, a high-performance array of raw SPADs. Many applications have taken advantage of SPAD image sensors created by the AQUA Lab, often achieving unprecedented performance. This includes FLIM (fluorescence lifetime imaging microscopy), FRET (Förster resonance energy transfer), PET (positron emission tomography), time-resolved Raman spectroscopy, LiDAR (light detection and ranging), quantum distillation, and quanta burst photography. The lab's spin-offs are active in automotive LiDAR, microscopy, and high-performance SPAD processing. The role of the AQUA Lab in CTAO is the creation of imaging sensors with unprecedented speed and dynamic range, as well as fast analog-to-digital converters for SiPMs.
Astronomy Laboratory – EPF Lausanne
The Laboratory of Astrophysics (LASTRO) of EPFL is involved in a wide range of projects in the domains of visible light and infrared astronomy (SDSS, DESI, 4MOST, MOONS ground-based facilities, Euclid space mission). Prof. Jean-Paul Kneib at LASTRO leads the Swiss participation in the Square Kilometer Array Observatory (SKAO), a next-generation radio array that will survey the radio sky with unprecedented sensitivity. LASTRO, in collaboration with CSCS and FNHW, is engaged in the management of the SKA Big Data, which is a major information and communication technology challenge for the upcoming decade. This emerging expertise in astronomical Big Data has allowed LASTRO to take responsibility for setting up and running one of the four Off-site Data Centres (Off-site DC), in collaboration with CSCS, and to join the collaboration around the LST sub-array of CTAO (Prof. Andr ii N eronov, Dr Volodymyr Savc henko). Understanding of astronomical sources visible in gamma rays with CTAO and in the radio band with SKAO requires analysis and interpretation of diverse multi-wavelength and multi-messenger (radio-to- gamma-ray, neutrino and possibly gravitational wave) data. The CTAO data management team at LASTRO is leading the Multi-Messenger Online Data Analysis (MMODA) platform based on a novel approach of cloud computing technology connected to the European Open Science Cloud and promoting Open Research Data practices.
Swiss National Supercomputing Centre – CSCS Lugano
CSCS develops and operates a high-performance computing and data research infrastructure that supports world-class science in Switzerland. CSCS resources are used by scientists for a diverse range of purposes – from high-resolution simulations to the analysis of complex data, to the development of software codes exploiting the potential of the next generation of computing architectures. CSCS has a strong track record in supporting the processing, analysis and storage of scientific data, and is investing heavily in new tools and computing systems to support data science applications. For more than 15 years, CSCS has been involved in the analysis of the many petabytes of data produced by scientific instruments such as the Large Hadron Collider (LHC) at CERN and is also hosting other scientific platforms such as the Materials Cloud from NCCR Marvel, eBrains from the Human Brain Project or the Numerical Weather Forecast from MeteoSwiss. Starting in early 2022, a joint effort of the CTAO and SKAO groups is establishing CSCS as an infrastructure for astrophysics. CSCS is one of the four off-site data centres for CTAO. The group is led by Mr Pablo Fernandez, who coordinates the international effort as data centre manager. They pursue synergies with SKAO which aims at optimising the usage of software (such as RUCIO), infrastructure services (such as Kubernetes) and the usage of GPUs in CTAO and SKAO on Alps, the new infrastructure at CSCS that will support these science platforms at scale.