arXiv subjects

Marija Šegedin Ferenc

Publications and source records attributed to Marija Šegedin Ferenc.

4 recordsLinked to original sources

arXiv2023

Tandem-ABALONETM Photosensors with $2\times2π$ Acceptance for Neutrino Astronomy

The primary goal of the novel photosensor technology called ABALONETM (U.S. Pat. 9,064,678) has been to enable the next-generation of astroparticle physics experiments to open new windows on the universe with large-area detectors of unprecedented performance, radio-purity, robustness, and integration flexibility. This foundational technology provides the means for modern, scalable and cost-effective production. The wide range of possible application-specific detector configurations can also make a difference in homeland security and medical imaging. Thus far, we have reduced to practice two such detector configurations: (i) the composite sandwich Panel assembly that hosts matrices of closely packed ABALONE units (U.S. Pat. 10,823,861), and, quite differently, the Tandem Detector Modules that host two back-to-back oriented ABALONE photosensors. This article for the first time presents the latter configuration, specifically designed to provide $2\times2π$ angular acceptance for neutrino astronomy and other large-area radiation detectors.

physics.ins-det↗

arXiv2019

Helium Migration through Photomultiplier Tubes -- The Probable Cause of the DAMA Seasonal Variation Effect

The interpretation of the DAMA seasonal variation pattern as a Dark Matter (DM) effect rests on the assumption that all sources of variable background have been excluded from the measurement. We have identified an overlooked background that mimics the DM signature -- a large, patently existing effect that has nothing to do with detection within the scintillators. This process takes place exclusively within the individual photomultiplier tubes (PMTs), with two familiar actors (thermionic electrons and helium atoms), two familiar processes (helium penetration of glass and ion afterpulsing), and a simple storyline: (a) After defeating the insulation of the DAMA detector, helium atoms from the variable local environment penetrate the PMT vacua; (b) Thermionic electrons from the PMT photocathode ionize helium atoms; (c) Secondary electrons from each helium ion impact in the photocathode form an afterpulse, and thus effectively boost and extend the waveform. We demonstrate that the accidental coincidences of such inflated dark noise waveforms, originating from any pair of PMTs, mimic scintillation events at a rate of $\approx$ 1 cpd/kg/keV, which is consistent with DAMA result. The reported seasonal variation of $\sim$ 1% thus implicates an equivalent variation of helium concentration in the local environment. We predict that the DAMA detector with a modified readout logic -- blinded for the DM scintillation events \textendash will measure the same, helium -- driven seasonal variation pattern as the original detector.

physics.ins-det↗

arXiv2018

ABALONE Photosensors for the IceCube Experiment

The ABALONE Photosensor Technology (U.S. Pat. 9064678) is a modern, scalable technology specifically invented for cost effective mass production, robustness, and high performance. We present the performance of advanced fused silica ABALONE Photosensors, developed specifically for the potential extension of the Ice Cube neutrino experiment, and stress tested for 120 days. The resulting performance makes a significant difference: intrinsic gain in the high 100 million range, total afterpulsing rate of only 0.005 ions per photoelectron, subnanosecond timing resolution, single photon sensitivity, and unique radiopurity and UV sensitivity, thanks to the fused silica components, at no additional cost to the assembly process.

physics.ins-det↗

arXiv2017

The Novel ABALONE Photosensor Technology: 4-Year Long Tests of Vacuum Integrity, Internal Pumping and Afterpulsing

The ABALONE Photosensor Technology (U.S. Patent 9064678 2015) has the capability of supplanting the expensive 80 year old Photomultiplier Tube (PMT) manufacture by providing a modern and cost effective alternative product. An ABALONE Photosensor comprises only three monolithic glass components, sealed together by our new thin film adhesive. In 2013, we left one of the early ABALONE Photosensor prototypes intact for continuous stress testing, and here we report its long term vacuum integrity. The exceptionally low ion afterpulsing rate (approximately two orders of magnitude lower than in PMTs) has been constantly improving. We explain the physical and technological reasons for this achievement. Due to the cost-effectiveness and the specific combination of features, including low level of radioactivity, integration into large-area panels, and robustness, this technology can open new horizons in the fields of fundamental physics, functional medical imaging, and nuclear security.

physics.ins-det↗