Sebastian Kempf
A5054001431- Superconducting and THz Device Technology
- Physics of Superconductivity and Magnetism
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Particle physics theoretical and experimental studies
- Particle Detector Development and Performance
- Radioactive Decay and Measurement Techniques
- Radio Frequency Integrated Circuit Design
- thermodynamics and calorimetric analyses
- Superconductivity in MgB2 and Alloys
- Quantum and electron transport phenomena
- Advanced Thermoelectric Materials and Devices
- Radiation Detection and Scintillator Technologies
- Scientific Research and Discoveries
- Quantum, superfluid, helium dynamics
- Semiconductor Lasers and Optical Devices
- Semiconductor Quantum Structures and Devices
- Machine Learning in Materials Science
- Microwave Engineering and Waveguides
- Magnetic Field Sensors Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced NMR Techniques and Applications
Karlsruhe Institute of Technology
2021-2025
Kirchhoff (Germany)
2016-2025
Institute for Physics
2025
Heidelberg University
2015-2024
Amorepacific (South Korea)
2024
Columbia University
2015
Weizmann Institute of Science
2015
Brown University
2009
Heidelberg University
2008
We present a comprehensive review of keV-scale sterile neutrino Dark Matter, collecting views and insights from all disciplines involved - cosmology, astrophysics, nuclear, particle physics in each case viewed both theoretical experimental/observational perspectives. After reviewing the role active neutrinos physics, we focus on context Matter puzzle. Here, first motivation for based challenges tensions purely cold scenarios. then round out discussion by critically summarizing known...
Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond Standard Model. Precision measurements kinematics weak interactions, 3H β-decay 163Ho electron capture (EC), represent only model independent approach to determine absolute scale neutrino masses. The experiment, ECHo, is designed reach sub-eV sensitivity on mass by means analysis calorimetrically measured spectrum nuclide 163Ho. maximum energy available for this decay,...
The Advanced Molybdenum-based Rare process Experiment (AMoRE) aims to search for neutrinoless double beta decay (0$\nu\beta\beta$) of $^{100}$Mo with $\sim$100 kg $^{100}$Mo-enriched molybdenum embedded in cryogenic detectors a dual heat and light readout. At the current, pilot stage AMoRE project we employ six calcium molybdate crystals total mass 1.9 kg, produced from $^{48}$Ca-depleted ($^{48\textrm{depl}}$Ca$^{100}$MoO$_4$). simultaneous detection heat(phonon) scintillation (photon)...
We present a measurement of the low-energy (0–60 keV) γ-ray spectrum produced in α decay U233 using dedicated cryogenic magnetic microcalorimeter. The energy resolution ∼10 eV, together with exceptional gain linearity, allows us to determine low-lying isomeric state Th229 four complementary evaluation schemes. most precise scheme determines isomer be 8.10(17) corresponding 153.1(32) nm, superseding precision previous values based on γ spectroscopy, and agreeing recent internal conversion...
Abstract AMoRE-II aims to search for neutrinoless double beta decay ( $$0\nu \beta $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>0</mml:mn> <mml:mi>ν</mml:mi> <mml:mi>β</mml:mi> </mml:mrow> </mml:math> ) with an array of 423 $$\hbox {Li}_2^{100}\hbox {MoO}_4$$ <mml:msubsup> <mml:mtext>Li</mml:mtext> <mml:mn>2</mml:mn> <mml:mn>100</mml:mn> </mml:msubsup> <mml:msub> <mml:mtext>MoO</mml:mtext> <mml:mn>4</mml:mn> </mml:msub> crystals operating in the cryogenic...
AMoRE searches for the neutrinoless double beta decay using 100 kg of enriched Mo100. Scintillating molybdate crystals coupled with a metallic magnetic calorimeter operate at milli-Kelvin temperatures to measure energy electrons emitted in decay. AMoRE-I is demonstrator full-scale AMoRE, operated Yangyang Underground Laboratory over two years. The exposure was 8.02 year (or 3.89 kgMo100 year), and total background rate near Q value 0.025±0.002 counts/keV/kg/year. We observed no indication...
We present two variants of a magnetic microcalorimeter with paramagnetic temperature sensors and integrated dc-superconducting quantum interference device readout for high-resolution x-ray emission spectroscopy. Each variant employs overhanging gold absorbers sensitive area 150 × μm2 thickness 3 μm, thus providing related efficiency &gt;98% photons up to 5 keV &gt;50% 10 keV. The first operated nominally but suffered from Joule power dissipation the Josephson junction shunt...
Metallic magnetic calorimeters (MMC) are calorimetric particle detectors, typically operated at temperatures below 100 mK, that make use of a paramagnetic temperature sensor to transform the rise upon absorption in detector into measurable flux change dc‐SQUID. During last years growing number groups has started develop MMC for wide variety applications, ranging from alpha‐, beta‐ and gamma‐spectrometry over spatially resolved detection accelerated molecule fragments arrays high resolution...
High-resolution maps of polarization anisotropies the cosmic microwave background (CMB) are in high demand, since discovery primordial B-modes patterns would confirm inflationary phase universe that have taken place before last scattering CMB at recombination epoch. Transition edge sensors (TES) and kinetic inductance detectors (MKID) predominant detector technologies cryogenic array-based instruments search for B-modes. We propose another type to be used survey: a magnetic microbolometer...
To reach ultra-low detection thresholds necessary to probe unprecedentedly low Dark Matter masses, target material alternatives and novel detector designs are essential. One such is superfluid ^4 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi /><mml:mn>4</mml:mn></mml:msup></mml:math> He which has the potential so far uncharted light parameter space at sub-GeV masses. The new “Direct search Experiment for Light dark matter”, DELight, will be using...
We report on the first demonstration of a scalable GHz frequency-domain readout metallic magnetic calorimeters (MMCs) using 64 pixel detector array that is read out by an integrated, on-chip microwave SQUID multiplexer. The optimized for detecting soft X-ray photons and multiplexer designed to provide signal rise time τrise&lt;400ns intrinsic energy sensitivity ϵ&lt;30h. This results in expected resolution ΔEFWHM&lt;10eV. measured τrise as low 90ns ΔEFWHM 50eV 5.9keV photons....
Highly precise measurements of the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mmultiscripts><a:mi>Tc</a:mi><a:mprescripts/><a:none/><a:mn>99</a:mn></a:mmultiscripts><a:mspace width="4pt"/><a:mi>β</a:mi></a:math> spectrum were performed in two laboratories using metallic magnetic calorimeters. Independent sample preparations, evaluation methods, and analyses yielded consistent results could be measured down to less than <c:math...
Abstract The AMoRE collaboration searches for neutrinoless double beta decay of $$^{100}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mn>100</mml:mn> </mml:mmultiscripts> </mml:math> Mo using molybdate scintillating crystals via low temperature thermal calorimetric detection. early phases the experiment, AMoRE-pilot and AMoRE-I, have demonstrated competitive discovery potential. Presently, AMoRE-II featuring a large detector array with...
Metallic microcalorimeters (MMCs) are cryogenic single-particle detectors that rely on a calorimetric detection principle. Due to their excellent energy resolution, close-to-ideal linear detector response, fast signal rise time and the potential for \SI{100}{\%} quantum efficiency, MMCs outperform conventional by several orders of magnitude in resolution. These attributes make them particularly interesting broad spectrum applications, including next-generation neutrino mass experiment based...
Metallic magnetic calorimeters are energy dispersive particle detectors that operated at temperatures below . Applied to x-ray spectroscopy they combine the high resolution of crystal spectrometers with large bandwidth semiconductor detectors. After absorption a photon its is converted into heat. A paramagnetic alloy converts temperature change magnetization read out by sensitive superconducting quantum interference device magnetometer. With such metallic calorimeter we performed two...
Abstract The determination of the effective electron neutrino mass via kinematic analysis beta and capture spectra is considered to be model-independent since it relies on energy momentum conservation. At same time precise description expected spectrum goes beyond simple phase space term. In particular for processes, many-body electron-electron interactions lead additional structures besides main resonances in calorimetrically measured spectra. A $$^{163}$$ <mml:math...