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We describe a new instrument, the Argonne Auger Radioisotope Microscope (ARM), capable of characterizing the Auger electron (AE) emission of radionuclides, including candidates relevant in nuclear medicine. Our approach relies on event-by-event ion–electron coincidence, time-of-flight, and spatial readout measurement to determine correlated electron multiplicity and energy distributions of Auger decays. We present a proof-of-principle measurement with the ARM using x-ray photoionization of stable krypton beyond the K -edge and identify a bifurcation in the electron multiplicity distribution depending on the emission of K-LX electrons. Extension of the ARM to the characterization of radioactive sources of AE emissions is enabled by the combination of two recent developments: (1) cryogenic buffer gas beam technology to introduce Auger emitters into the detection region with well-defined initial conditions, and (2) large-area micro-channel plate detectors with multi-hit detection capabilities to simultaneously detect multiple electrons emitted in a single decay.

Abstract We describe a new instrument, the Argonne Auger Radioisotope Microscope (ARM), capable of characterizing the Auger electron (AE) emission of radionuclides, including candidates relevant in nuclear medicine. Our approach relies on event-by-event ion–electron coincidence, time-of-flight, and spatial readout measurement to determine correlated electron multiplicity and energy distributions of Auger decays. We present a proof-of-principle measurement with the ARM using x-ray photoionization of stable krypton beyond the K -edge and identify a bifurcation in the electron multiplicity distribution depending on the emission of K-LX electrons. Extension of the ARM to the characterization of radioactive sources of AE emissions is enabled by the combination of two recent developments: (1) cryogenic buffer gas beam technology to introduce Auger emitters into the detection region with well-defined initial conditions, and (2) large-area micro-channel plate detectors with multi-hit detection capabilities to simultaneously detect multiple electrons emitted in a single decay.

We demonstrate laser frequency stabilization with at least 6 GHz of offset tunability using an in-phase/quadrature (IQ) modulator to generate electronic sidebands (ESB) on a titanium sapphire laser at 714 nm and we apply this technique to the precision spectroscopy of \\(^{226}\\)Ra, and \\(^{225}\\)Ra. By locking the laser to a single resonance of a high finesse optical cavity and adjusting the lock offset, we determine the frequency difference between the magneto-optical trap (MOT) transitions in the two isotopes to be \\(2630.0\\pm0.3\\) MHz, a factor of 29 more precise than the previously available data. Using the known value of the hyperfine splitting of the \\(^{3}P_{1}\\) level, we calculate the isotope shift for the \\(^{1}S_{0}\\) to \\(^{3}P_{1}\\) transition to be \\(2267.0\\pm2.2\\) MHz, which is a factor of 8 more precise than the best available value. Our technique could be applied to countless other atomic systems to provide unprecedented precision in isotope shift spectroscopy and other relative frequency comparisons.

We describe a new instrument, the Argonne Auger-Meitner Radioisotope Microscope (ARM), capable of characterizing the Auger-Meitner electron emission of radionuclides, including candidates relevant in nuclear medicine. Our approach relies on event-by-event coincidence ion, electron time-of-flight and spatial readout measurement to determine correlated electron multiplicity and energy distributions of Auger-Meitner decays. We present a proof-of-principle measurement with the ARM using X-ray photoionization of stable krypton beyond the K-edge and identify a bifurcation in the electron multiplicity distribution depending on the emission of K-LX electrons. Extension of the ARM to the characterization of radioactive sources of Auger-Meitner electron emissions is enabled by the combination of two recent developments: (1) cryogenic buffer gas beam technology, which enables well-defined initial conditions, gas-phase, high activity introduction of Auger-Meitner emitters into the detection region, and (2) large-area micro-channel plate detectors with multi-hit detection capabilities, which enables the simultaneous detection of many electrons emitted in a single decay. The ARM will generate new experimental data on Auger-Meitner multiplicities that can be used to benchmark atomic relaxation and decay models. As the multiplicities are binned by energy, this data will provide insight into the low-energy regime of Auger-Meitner electrons where intensity calculations are most challenging and experimental data is limited. In particular, accurate multiplicity data of the low-energy regime can be used to inform oncological dosimetry models, where electron energies less than 500 eV are known to be effective in damaging DNA and cell membranes.

Motional ground state cooling and internal state preparation are important elements for quantum logic spectroscopy (QLS), a class of quantum information processing. Since QLS does not require the high gate fidelities usually associated with quantum computation and quantum simulation, it is possible to make simplifying choices in ion species and quantum protocols at the expense of some fidelity. Here, we report sideband cooling and motional state detection protocols for \\(^{138}\\)Ba\\(^+\\) of sufficient fidelity for QLS without an extremely narrowband laser or the use of a species with hyperfine structure. We use the two S\\(_{1/2}\\) Zeeman sublevels of \\(^{138}\\)Ba\\(^+\\) to Raman sideband cool a single ion to the motional ground state. Because of the small Zeeman splitting, near-resonant Raman sideband cooling of \\(^{138}\\)Ba\\(^+\\) requires only the Doppler cooling lasers and two additional AOMs. Observing the near-resonant Raman optical pumping fluorescence, we estimate a final average motional quantum number \\(\\bar{n}\\approx0.17\\). We additionally employ a second, far-off-resonant laser driving Raman \\(\\pi\\)-pulses between the two Zeeman sublevels to provide motional state detection for QLS and to confirm the sideband cooling efficiency, measuring a final \\(\\bar{n} = 0.15(6)\\).

The Ra EDM experiment uses a pair of high voltage electrodes to measure the atomic electric dipole moment of \\(^{225}\\)Ra. We use identical, plane-parallel electrodes with a primary high gradient surface of 200 mm\\(^2\\) to generate reversible DC electric fields. Our statistical sensitivity is linearly proportional to the electric field strength in the electrode gap. We adapted surface decontamination and processing techniques from accelerator physics literature to chemical polish and clean a suite of newly fabricated large-grain niobium and grade-2 titanium electrodes. Three pairs of niobium electrodes and one pair of titanium electrodes were discharge-conditioned with a custom high voltage test station at electric field strengths as high as \\(+52.5\\) kV/mm and \\(- 51.5\\) kV/mm over electrode gap sizes ranging from 0.4 mm to 2.5 mm. One pair of large-grain niobium electrodes was discharge-conditioned and validated to operate at \\(\\pm 20\\) kV/mm with steady-state leakage current \\(\\leq 25\\) pA (\\(1\\sigma\\)) and a polarity-averaged \\(98 \\pm 19\\) discharges per hour. These electrodes were installed in the Ra EDM experimental apparatus, replacing a copper electrode pair, and were revalidated to \\(\\pm 20\\) kV/mm. The niobium electrodes perform at an electric field strength 3.1 times larger than the legacy copper electrodes and are ultimately limited by the maximum output of our 30 kV bipolar power supply.

This whitepaper is an outcome of the workshop Intersections between Nuclear Physics and Quantum Information held at Argonne National Laboratory on 28-30 March 2018 [www.phy.anl.gov/npqi2018/]. The workshop brought together 116 national and international experts in nuclear physics and quantum information science to explore opportunities for the two fields to collaborate on topics of interest to the U.S. Department of Energy (DOE) Office of Science, Office of Nuclear Physics, and more broadly to U.S. society and industry. The workshop consisted of 22 invited and 10 contributed talks, as well as three panel discussion sessions. Topics discussed included quantum computation, quantum simulation, quantum sensing, nuclear physics detectors, nuclear many-body problem, entanglement at collider energies, and lattice gauge theories.

Background: Octupole-deformed nuclei, such as that of \\(^{225}\\)Ra, are expected to amplify observable atomic electric dipole moments (EDMs) that arise from time-reversal and parity-violating interactions in the nuclear medium. In 2015, we reported the first \"proof-of-principle\" measurement of the \\(^{225}\\)Ra atomic EDM. Purpose: This work reports on the first of several experimental upgrades to improve the statistical sensitivity of our \\(^{225}\\)Ra EDM measurements by orders of magnitude and evaluates systematic effects that contribute to current and future levels of experimental sensitivity. Method: Laser-cooled and trapped \\(^{225}\\)Ra atoms are held between two high voltage electrodes in an ultra high vacuum chamber at the center of a magnetically shielded environment. We observe Larmor precession in a uniform magnetic field using nuclear-spin-dependent laser light scattering and look for a phase shift proportional to the applied electric field, which indicates the existence of an EDM. The main improvement to our measurement technique is an order of magnitude increase in spin precession time, which is enabled by an improved vacuum system and a reduction in trap-induced heating. Results: We have measured the \\(^{225}\\)Ra atomic EDM to be less than \\(1.4\\times10^{-23}\\) \\(e\\) cm (95% confidence upper limit), which is a factor of 36 improvement over our previous result. Conclusions: Our evaluation of systematic effects shows that this measurement is completely limited by statistical uncertainty. Combining this measurement technique with planned experimental upgrades we project a statistical sensitivity at the \\(1\\times10^{-28}\\) \\(e\\) cm level and a total systematic uncertainty at the \\(4\\times10^{-29}\\) \\(e\\) cm level.

Palpitations are common but understudied in breast cancer survivors (BCS). Palpitations may relate to severe arrhythmias, resulting in life-threatening events or cardiac death. However, how palpitations relate to arrhythmias and electrocardiogram abnormalities is unknown. The purpose of the proposed project is to demonstrate the feasibility of using wearable electrocardiogram (ECG) monitors in BCS to detect and characterize arrhythmias associated with self-reported palpitations and to gain a comprehensive understanding of palpitations using an investigator-designed Palpitations Assessment Tool (PAT). We will conduct a prospective cohort study of 84 BCS (54 BCS with palpitations and 30 without). Eligible participants will include breast cancer patients who completed chemotherapy at least six months ago and no more than three years ago. Palpitations and arrhythmias will be recorded using an ECG monitor for two 7-day periods, one month apart. Feasibility, acceptability, and retention, as measured by completion of the PAT and monitored wearing for 7 days, will be evaluated using frequency distribution in recruitment and retention logs. We will generate descriptive summaries of the prevalence of primary outcomes, including frequency of palpitations and changes in cardiac rate and rhythm, and examine associations between these outcomes.

Climatic conditions that challenge human thermoregulatory capacity currently affect around a quarter of the world’s population annually. Such conditions are projected to increase in line with CO 2 emissions particularly in the humid tropics. Climate change can increase the risk of conditions that exceed human thermoregulatory capacity 1 , 2 , 3 , 4 , 5 , 6 . Although numerous studies report increased mortality associated with extreme heat events 1 , 2 , 3 , 4 , 5 , 6 , 7 , quantifying the global risk of heat-related mortality remains challenging due to a lack of comparable data on heat-related deaths 2 , 3 , 4 , 5 . Here we conducted a global analysis of documented lethal heat events to identify the climatic conditions associated with human death and then quantified the current and projected occurrence of such deadly climatic conditions worldwide. We reviewed papers published between 1980 and 2014, and found 783 cases of excess human mortality associated with heat from 164 cities in 36 countries. Based on the climatic conditions of those lethal heat events, we identified a global threshold beyond which daily mean surface air temperature and relative humidity become deadly. Around 30% of the world’s population is currently exposed to climatic conditions exceeding this deadly threshold for at least 20 days a year. By 2100, this percentage is projected to increase to ∼48% under a scenario with drastic reductions of greenhouse gas emissions and ∼74% under a scenario of growing emissions. An increasing threat to human life from excess heat now seems almost inevitable, but will be greatly aggravated if greenhouse gases are not considerably reduced.