Optical modules for the neutrino telescope KM3NeT Kalekin, O.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
1
Journal Article
Recenzirano
KM3NeT is a future deep-sea research infrastructure hosting a neutrino telescope with a volume of at least one cubic kilometer to be constructed in the Mediterranean Sea. The experiment aims to ...detect high-energy cosmic neutrinos using a 3D array of optical modules to collect the Cherenkov light induced by charged particles in the water. Upward going muons and showers produced in neutrino interactions with the surrounding matter will allow the search and study of possible sources of extra-terrestrial neutrinos. The design of optical modules makes an important impact on the performance and cost of the KM3NeT project. Several different optical module configurations are under consideration; based on glass pressure spheres containing: a large (10in.) hemispherical photomultiplier tube (with a multi-anode version as an option); 25–31 3in. photomultiplier tubes, or a crystal scintillator-based hybrid device (X-HPD). The features and advantages of each optical module design are discussed.
The Cherenkov Telescope Array (CTA) is a future gamma-ray observatory that is planned to significantly improve upon the sensitivity and precision of the current generation of Cherenkov telescopes. ...The observatory will consist of several dozens of telescopes with different sizes and equipped with different types of cameras. Of these, the FlashCam camera system is the first to implement a fully digital signal processing chain which allows for a traceable, configurable trigger scheme and flexible signal reconstruction. As of autumn 2016, a prototype FlashCam camera for the medium-sized telescopes of CTA nears completion. First results of the ongoing system tests demonstrate that the signal chain and the readout system surpass CTA requirements. The stability of the system is shown using long-term temperature cycling.
•A full-scale prototype of the FlashCam Cherenkov camera is in operation.•System level testing and characterisation in a dark room is ongoing.•The performances of the data acquisition and the signal chain have been verified.•The system is stable over long periods and robust against temperature variations.
Context. Very high-energy (VHE, E > 100 GeV) γ-ray data are a valuable input for multi-wavelength and multi-messenger (e.g. combination with neutrino data) studies. Aims. We aim at the conservation ...and homogenization of historical, current, and future VHE γ-ray-data on active galactic nuclei (AGN). Methods. We have collected lightcurve data taken by major VHE experiments since 1991 and combined them into long-term lightcurves for several AGN, and now provide our collected datasets for further use. Due to the lack of common data formats in VHE γ-ray astronomy, we have defined relevant datafields to be stored in standard data formats. The time variability of the combined VHE lightcurve data was investigated, and correlation with archival X-ray data collected by RXTE/ASM tested. Results. The combination of data on the prominent blazar Mrk 421 from different experiments yields a lightcurve spanning more than a decade. From this combined dataset we derive an integral baseline flux from Mrk 421 that must be lower than 33% of the Crab Nebula flux above 1 TeV. The analysis of the time variability yields log-normal flux variations in the VHE-data on Mrk 421. Conclusions. Existing VHE data contain valuable information concerning the variability of AGN and can be an important ingredient for multi-wavelength or multi-messenger studies. In the future, upcoming and planned experiments will provide more data from many transient objects, and the interaction of VHE astronomy with classical astronomy will intensify. In this context a unified and exchangeable data format will become increasingly important.
Status of the PMT development for KM3NeT Classen, L.; Kalekin, O.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2013, Letnik:
725
Journal Article
Recenzirano
KM3NeT is a future large volume (multi km3) neutrino telescope to be constructed at the bottom of the Mediterranean Sea. The detection volume will be instrumented using multi-PMT optical modules, ...consisting of an array of small photomultipliers housed in a spheric glass vessel. Three companies are presently developing 3-in. PMTs as candidates for the construction of these modules. Main characteristics of the prototypes, such as quantum efficiency, single electron gain, dark current and transit time spread, are required to meet the specification established by the KM3NeT consortium.
We report on the current stage of PMT development and recent results of tests performed at the Erlangen Centre for Astroparticle Physics.
PMT measurements in Antares Creusot, A.; Kalekin, O.; Kulikovskiy, V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2013, Letnik:
725
Journal Article
Recenzirano
The comparison of simulated and real data in the Antares experiment shows some discrepancies. Differences are observed in the charge distribution of background hits, in the trigger efficiency, and in ...the counting rate of 40K decay induced events. These discrepancies must be understood to improve data analysis. It turns out that most of the simulated/real data mismatch can be explained by a undetailed description of the PMT response in the simulations. PMT parameters such as late pulses, afterpulses and angular acceptance have been reviewed and when necessary measurements of these parameters have been carried out using Antares PMTs and optical modules. In addition a more detailed simulation of the angular acceptance of the Antares optical module has been performed. Results of these studies are presented.
Trigger performance verification of the FlashCam prototype camera Sailer, S.; Werner, F.; Hermann, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
Odprti dostop
FlashCam is a camera proposed for the medium-sized telescopes of the Cherenkov Telescope Array (CTA). We compare camera trigger rates obtained from measurements with the camera prototype in the ...laboratory and Monte Carlo simulations, when scanning the parameter space of the fully-digital trigger logic and the intensity of a continuous light source mimicking the night sky background (NSB) during on-site operation. The comparisons of the measured data results to the Monte Carlo simulations are used to verify the FlashCam trigger logic and the expected trigger performance.
Advanced
LIGO
detected a significant gravitational wave signal (GW170104) originating from the coalescence of two black holes during the second observation run on January 4th, 2017. An all-sky ...high-energy neutrino follow-up search has been made using data from the
Antares
neutrino telescope, including both upgoing and downgoing events in two separate analyses. No neutrino candidates were found within
±
500
s around the GW event time nor any time clustering of events over an extended time window of
±
3
months. The non-detection is used to constrain isotropic-equivalent high-energy neutrino emission from GW170104 to less than
∼
1.2
×
10
55
erg for a
E
-
2
spectrum. This constraint is valid in the energy range corresponding to the 5–95% quantiles of the neutrino flux 3.2 TeV; 3.6 PeV, if the GW emitter was below the
Antares
horizon at the alert time.
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