Wavelength-shifting light traps for SWGO and other applications

Wavelength-shifting (WLS) materials contain molecules that absorb light and reemit at longer wavelengths. They can be used for light detection because they provide a large effective area for low cost and they are able to efficiently trap and guide light because of total internal reflection processes. We are currently developing such a WLS detector, considering two main designs: A single-shift design with one wavelength shift (tile) and a double-shift design with two wavelength shifts (tile and fiber). As photodetectors we use small Silicon photomultipliers (SiPMs) with a high photon detection efficiency (PDE) and single-photon sensitivity. The double-shift layout goes at the expense of detection efficiency. In this design however, light is channeled to the two ends of a fiber, thus requiring a reduced photosensitive area compared to the single-shift layout. We will present the results of our measurements and show that light traps and SiPMs together represent a promising alternative to PMTs in case of a non-focused light beam. For the special case of SWGO, the application of light traps is also motivated by a possible improvement of the gamma/hadron separation, using a one-chamber tank with an array of wavelength-shifting light traps instead of a (two-chamber) tank with PMTs. Besides SWGO, new WLS detectors could also constitute useful and cheap technology for other experiments and use cases. The contribution summarizes our motivation and efforts to build a light trap detection module and to characterize its properties in terms of costs, temporal performance and detection efficiency.Comment: 8 pages, 9 figures, Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 202

A possible solution for dinamically managing virtual environments

In modern distributed computer systems (clusters and computing GRIDs) a new class of problems, due to the increasing heterogeneity of users’ needs, have to be tackled by the administrators. One possible solution is to create ondemand virtual working environments tailored on the user’s requirements. Hence the need for an architecture to manage dynamically such environments. In this work we propose a possible solution based on the use of Virtual Machines (Xen), the implementation of a Virtual Machine Manager, capable of creation, destruction and migration of the virtualized working environments. The information will be collected using a client-server mechanism, to allow the manager to deploy preconfigured Virtual Machines on the available hardware resources. When a new execution environment became active, it is automatically recognized by the Batch System Manager and is then ready to be used