C. R. Natzke
A5053094828- Nuclear physics research studies
- Radiation Detection and Scintillator Technologies
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Atomic and Molecular Physics
- Atomic and Subatomic Physics Research
- Astronomical and nuclear sciences
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Particle physics theoretical and experimental studies
- Particle Detector Development and Performance
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Medical Imaging Techniques and Applications
- Quantum Chromodynamics and Particle Interactions
- Atmospheric Ozone and Climate
- Radiation Therapy and Dosimetry
- Scientific Research and Discoveries
- Advanced NMR Techniques and Applications
- Respiratory Support and Mechanisms
- Chemistry and Stereochemistry Studies
- Astro and Planetary Science
- Radioactivity and Radon Measurements
- Radioactive contamination and transfer
- Photocathodes and Microchannel Plates
Colorado School of Mines
2017-2024
TRIUMF
2020-2024
Abstract The nEXO neutrinoless double beta (0 νββ ) decay experiment is designed to use a time projection chamber and 5000 kg of isotopically enriched liquid xenon search for the in 136 Xe. Progress detector design, paired with higher fidelity its simulation an advanced data analysis, based on one used final results EXO-200, produce sensitivity prediction that exceeds half-life 10 28 years. Specifically, improvements have been made understanding production scintillation photons charge as...
The excited states of N=44 ^{74}Zn were investigated via γ-ray spectroscopy following ^{74}Cu β decay. By exploiting γ-γ angular correlation analysis, the 2_{2}^{+}, 3_{1}^{+}, 0_{2}^{+}, and 2_{3}^{+} in firmly established. branching E2/M1 mixing ratios for transitions deexciting measured, allowing extraction relative B(E2) values. In particular, 2_{3}^{+}→0_{2}^{+} 2_{3}^{+}→4_{1}^{+} observed first time. results show excellent agreement with new microscopic large-scale shell-model...
The cross-shell excited states of $^{34}\mathrm{Si}$ have been investigated via $\ensuremath{\beta}$ decays the ${4}^{\ensuremath{-}}$ ground state and ${1}^{+}$ isomeric $^{34}\mathrm{Al}$. Since valence protons neutrons occupy different major shells in as well intruder $^{34}\mathrm{Al}$, levels are populated allowed decays. Spin assignments to such were established through $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ angular correlation analysis for negative-parity with...
Understanding reflective properties of materials and photodetection efficiency (PDE) photodetectors is important for optimizing energy resolution sensitivity the next generation neutrinoless double beta decay, direct detection dark matter, neutrino oscillation experiments that will use noble liquid gases, such as nEXO, DARWIN, DarkSide-20k, DUNE . Little information currently available about reflectivity PDE in because measurements are difficult to conduct a cryogenic environment at short...
The $^{80}\mathrm{Ge}$ structure was investigated in a high-statistics $\ensuremath{\beta}$-decay experiment of $^{80}\mathrm{Ga}$ using the GRIFFIN spectrometer at TRIUMF-ISAC through $\ensuremath{\gamma}$, $\ensuremath{\beta}\text{\ensuremath{-}}e$, $e\text{\ensuremath{-}}\ensuremath{\gamma}$, and $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ spectroscopy. No evidence found for recently reported ${0}_{2}^{+}$ 639-keV level suggested as low-energy shape coexistence...
Characterization of the vacuum ultraviolet (VUV) reflectance silicon photomultipliers (SiPMs) is important for large-scale SiPM-based photodetector systems. We report angular dependence specular in a SiPMs manufactured by Fondazionc Bruno Kessler (FBK) and Hamamatsu Photonics K.K. (HPK) over wavelengths ranging from 120 nm to 280 nm. Refractive index extinction coefficient thin silicon-dioxide film deposited on surface FBK are derived data wafer with same oxide as SiPMs. The diffuse also...
Neutrinoless double beta decay is one of the most sensitive probes for new physics beyond Standard Model particle physics. One isotopes under investigation <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mmultiscripts><a:mi>Xe</a:mi><a:mprescripts/><a:none/><a:mn>136</a:mn></a:mmultiscripts></a:math>, which would into <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mmultiscripts><b:mi>Ba</b:mi><b:mprescripts/><b:none/><b:mn>136</b:mn></b:mmultiscripts></b:math>. Detecting...
We have performed the first direct measurement of 83Rb(p,g) radiative capture reaction cross section in inverse kinematics using a radioactive beam 83Rb at incident energies 2.4 and 2.7 A MeV. The measured an effective relative kinetic energy Ecm = 2.393 MeV, which lies within relevant window for core collapse supernovae, is smaller than prediction statistical model calculations. This leads to abundance 84Sr produced astrophysical p process being higher previously calculated. Moreover,...
The r-process has been shown to be robust in reproducing the abundance distributions of heavy elements, such as europium, seen ultra-metal poor stars. In contrast, observations elements 26 < Z 47 display overabundances relative model predictions. A proposed additional source early nucleosynthesis is weak neutrino-driven winds core-collapse supernovae. It that this site ( α ,n) reactions are both crucial and main uncertainty model-based Aiming improve certainty predictions, cross section...
nEXO is a proposed experiment to search for the neutrino-less double beta decay (0νββ) of 136Xe in tonne-scale liquid xenon time projection chamber (TPC) . The TPC will be equipped with charge collection tiles form anode. In this work, reconstruction performance anode design studied dedicated simulation package. A multi-variate method and deep neural network are developed distinguish simulated 0νββ signals from backgrounds arising trace levels natural radioactivity detector materials. These...
We have measured the cross section of $^{83}$Rb(p,$\gamma)^{84}$Sr radiative capture reaction in inverse kinematics using a radioactive beam $^{83}$Rb at incident energies 2.4 and $2.7 A$ MeV. Prior to measurement, $^{84}$Kr(p,$\gamma)^{85}$Rb was stable $^{84}$Kr an energy The effective relative kinetic these measurements lie within relevant window for $\gamma$ process supernovae. central values partial sections both reactions were found be $0.17-0.42$ times predictions statistical model...
The properties of a nanosecond isomer in $^{32}$Si, disputed previous studies, depend on the evolution proton and neutron shell gaps near `island inversion'. We have placed at 5505.2(2) keV with $J^π = 5^-$, decaying primarily via an $E3$ transition to $2^+_1$ state. strength 0.0841(10) W.u. is unusually small suggests that this dominated by $(νd_{3/2})^{-1} \otimes (νf_{7/2})^{1}$ configuration, which sensitive $N=20$ gap. A newly observed $4^+_1$ state 5881.4(13) keV; its energy enhanced...
Silicon photomultipliers are regarded as a very promising technology for next-generation, cutting-edge detectors low-background experiments in particle physics. This work presents systematic reflectivity studies of Photomultipliers (SiPM) and other samples liquid xenon at vacuum ultraviolet (VUV) wavelengths. A dedicated setup the University Münster has been used that allows to acquire angle-resolved reflection measurements various immersed with 0.45° angular resolution. Four investigated...
A high-precision branching ratio measurement for the superallowed Fermi ${\ensuremath{\beta}}^{+}$ emitter $^{62}\mathrm{Ga}$ was performed with Gamma-Ray Infrastructure Fundamental Investigations of Nuclei (GRIFFIN) spectrometer at Isotope Separator and Accelerator (ISAC) radioactive ion beam facility TRIUMF. The high efficiency GRIFFIN allowed 63 $\ensuremath{\gamma}$-ray transitions, intensities down to $\ensuremath{\approx}1$ part per million (ppm)...
A high-precision half-life measurement for the superallowed Fermi $\beta^+$ emitter $^{22}$Mg was performed at TRIUMF-ISAC facility using a 4$\pi$ proportional gas counter. The result of $T_{1/2} = 3.87400 \pm 0.00079$ s is factor 3 more precise than previously adopted world average and resolves discrepancy between two published measurements.
Electron-neutrino charged-current interactions with xenon nuclei were modeled in the nEXO neutrinoless double-<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>β</a:mi></a:math> decay detector (<c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mo>∼</c:mo><c:mn>5</c:mn></c:math> metric ton, 90% <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"...
Background: Detailed spectroscopy of neutron-rich, heavy, deformed nuclei is broad interest for nuclear astrophysics and structure. Nuclei in the $r$-process path following freeze-out region impact resulting abundance distribution, structure midshell both proton neutron number helps to understand evolution subshell gaps large deformation these nuclei.Purpose: We aim improve understanding $^{160}\mathrm{Gd}$, specifically ${K}^{\ensuremath{\pi}}={4}^{+}$ bands, as well study...