Lake Deployment of Southern Wide-field Gamma-ray Observatory (SWGO) Detector Units

The Southern Wide-field Gamma-ray Observatory (SWGO) will be a next-generation high altitude gamma-ray survey observatory in the southern hemisphere consisting of an array of water cherenkov detectors. With its energy range, wide field of view, large duty cycle and location it will complement the other existing and planned gamma-ray observatories. In this contribution we describe the lake concept for SWGO, an alternative to a HAWC-like design with individual water tanks and a LHAASO-style design with artificial ponds. In the lake concept, bladders filled with clean water are deployed near the surface of a natural lake, where each bladder is a light-tight stand-alone unit containing one or more photosensors. We will give an overview of the advantages and challenges for this design concept and describe the first results obtained from prototyping

Technological options for the Southern Wide-field Gamma-ray Observatory (SWGO) and current design status

The SWGO Collaboration is in the process of designing and prototyping a wide field of view, high duty cycle complement to CTA and the existing ground-based particle detectors of the Northern Hemisphere (HAWC and LHAASO). In this contribution, we will compare the various technological options for designing the detector and present an overarching system design accommodating them. We will introduce a feasible reference configuration that is used for the first large-scale simulations and cost estimates, and show ongoing prototyping work focused on reaching a maintenance-free and cost-effective detector

The search for high altitude sites in South America for the SWGO detector

The Southern Wide-field Gamma-ray Observatory (SWGO) is a project for a new generation of extensive air shower front detectors, based primarily on the water Cherenkov technique, to be located in the Southern Hemisphere, where no other instrument of that kind is currently operating in the TeV gamma-ray energy range. The reference configuration of SWGO foresees an array of about 6, 000 water Cherenkov tanks deployed over a circle of 320 m diameter, about 80, 000 m2 area. In order to reach a sensitivity at energies around and below 1 TeV competitive with current and future detectors, SWGO will be placed at altitude above 4, 400 m a.s.l. Preliminary site searches have found several candidate sites in Argentina, Bolivia, Chile and Peru. The major challenge will be the water provision, considering that at least 105 m3 of water will be required. This poster will present the challenges and status of the SWGO site search in South America

Gamma/hadron discrimination using a small-WCD with four PMTs

The Southern Wide-field Gamma-ray Observatory (SWGO) is the next-generation gamma-ray observatory, currently in an R&D phase. The experiment is expected to have a large array of water Cherenkov detectors (WCD) placed at a high elevation (> 4.4 km a.s.l.) in South America. Here we present a WCD concept with reduced surface area and height of stations comprising four PMTs at the bottom. We show that it is possible to reach an excellent gamma/hadron discrimination by analysing the data gathered by this station with machine learning techniques. Such performance can be achieved by analysing the shower patterns at the ground or through the PMTs signal time structure to tag muons. Moreover, it is shown that the station's performance does not depend on the array configuration (dense or sparse) nor on the shower inclination (θ< 40◦). Such a concept reduces the cost associated with the transport of massive amounts of water to high elevation sites while keeping a high physics performance. Therefore, it could be a good candidate station for SWGO, enabling to reach good sensitivities from low energies (∼ 100 GeV) up to the PeV region, covering large ground surface areas (few square km)