garded as a general introduction to the interesting new field of atomic medicine, it covers a vast amount of information on radioisotopes which are used in medical research, diagnosis, and therapy. The background of nuclear physics on each aspect of this new field of medicine is concisely explained. The medical use of high energy particle accelerators such as cyclotron, betatron, synchrotron, and linear accelerators are briefly described. The linear accelerator is considered as the machine which has real practical value in radiotherapy. In radiotherapy today in England there is considerable competition between linear accelerator and large telecurie units, such as Cobalt-60 or Cesium-137. Both these developments are important by-products of atomic energy development. The three dangerous biological effects of radiation to man are discussed in some detail: (1) immediate danger of tissue damage from individual high exposure, (2) long-term danger of chronic damage to tissue with possible induction of cancer, (3) remote but important danger of permanent genetic damage that may seriously affect future generations. The common levels of radiation exposure are listed in detail based on the data published in Great Britain. Some interesting estimated figures on radiation received by the whole population of Great Britain to reproductive organs in the first 30 years of life as a genetic hazard are abstracted as follows: Natural body radioactivity, 690 mr. The dose required to double human mutation rate is estimated to be 50,000 mr. The author also stresses the opinion that genetic damage by radiation is not yet fully understood and must be worked out as one of our most urgent problems. The material chosen is mainly from the British sources and is based on a comprehensive review of the literature of the subject. The illustrations .are excellent but no bibliography is appended. It is easy and pleasing to read and it should be recommended to medical students, nurses, and physicians who want to have a general and up-to-date view of this subject. "How does development produce entities which have Form, in the sense of integration or wholeness; how does evolution bring into being organisms which have Ends, in the sense of goal-seeking or directiveness?" An examination of these questions provides the unifying theme for this collection of essays which are Professor Waddington's most recent contribution to theoretical biology. Although portions of four of the five essays have appeared elsewhere in different form, they are essentially new and contain much …
We present numerical quantum mechanical description of the formation of low-energy bound states between a dark atom [Formula: see text]He (a neutral atom-like composite of a heavy doubly charged particle [Formula: see text] and a helium nucleus) and ordinary nuclei, with a focus on sodium and iodine. The total effective interaction potential is reconstructed by combining self-consistent nuclear, electromagnetic and centrifugal contributions. For the [Formula: see text]He-Na system, a single shallow bound state is found with binding energy in the 1-6 keV range, which naturally accounts for the annual modulation signal observed by the DAMA/LIBRA experiment if the radiative capture proceeds via an E1 transition. For the [Formula: see text]He-I system, the potential well is much deeper, leading to bound states with energies of order hundreds of keV to MeV and to strongly suppressed capture cross sections, in agreement with the absence of a modulation signal from iodine and with the upper limits on high-energy gamma rays from DAMA. The framework provides a consistent explanation for the target-material dependence in direct dark matter searches and highlights the importance of quantum effects of atomic and nuclear physics in the interpretation of underground detector signals.
Abstract We consider QCD with n f = 0 and n f = 3 light quarks. We present the most up-to-date determinations for the normalizations of the leading renormalons of the pole mass, the singlet static potential, the octet static potential, and the gluelump energy. These read Z m MS ¯ $$ {Z}_m^{\overline{\textrm{MS}}} $$ = − Z V s MS ¯ / 2 $$ -{Z}_{V_s}^{\overline{\textrm{MS}}}/2 $$ = {0.604(17), 0.551(20)}, Z V o MS ¯ $$ {Z}_{V_o}^{\overline{\textrm{MS}}} $$ = {0.136(8), 0.121(13)}, and Z A MS ¯ $$ {Z}_A^{\overline{\textrm{MS}}} $$ = {–1.343(36), –1.224(43)}, for n f = 0 and n f = 3, respectively. For n f = 0, we obtain two independent renormalization group invariant and renormalization scale independent determinations of the energy of the ground state gluelump in the principal value summation scheme: Λ B PV = 2.47 9 r 0 − 1 $$ {\Lambda}_B^{\textrm{PV}}=2.47(9){r}_0^{-1} $$ and Λ B PV = 2.38 11 r 0 − 1 $$ {\Lambda}_B^{\textrm{PV}}=2.38(11){r}_0^{-1} $$ where r 0 − 1 $$ {r}_0^{-1} $$ ≈ 400 MeV. Averaging these results, we obtain Λ B PV = 2.44 7 r 0 − 1 $$ {\Lambda}_B^{\textrm{PV}}=2.44(7){r}_0^{-1} $$ .
Nuclear and particle physics. Atomic energy. Radioactivity
Francesca Pacifico, Paolo Pergola, Charlotte Sleight
Abstract Holographic correlators on the celestial sphere of Minkowski space were recently defined in [1] as the extrapolation of bulk time-ordered correlation functions to the celestial sphere. In this work we explore the Mellin representation of such celestial correlators, which is based on the Mellin representation of conformal correlators introduced by Mack in 2009. Perturbative celestial Mellin amplitudes have some similarities with Mellin amplitudes for AdS Witten diagrams: they are meromorphic functions of the Mellin variables, where contact diagrams have polynomial Mellin amplitudes and particle exchanges are encoded by a specific set of poles. We find the Mellin representation to be a useful tool to study and to compute celestial correlators, and we give various examples in scalar field theories at both tree and loop level, for both massive and massless fields. We also discuss the non-perturbative structure of celestial Mellin amplitudes following from the Källén-Lehmann spectral representation of bulk two-point functions.
Nuclear and particle physics. Atomic energy. Radioactivity
Abstract The count of microstates for supersymmetric black holes is typically obtained from a supersymmetric index in weakly-coupled string theory. We find the saddles in the gravitational path integral corresponding to this index in a general theory of N $$ \mathcal{N} $$ = 2 supergravity in asymptotically flat space. This saddle exhibits a new attractor mechanism which explains the agreement between the string theory index and the macroscopic entropy. These saddles are smooth, complex Euclidean spinning black holes that are supersymmetric but not extremal, i.e. they are formally finite-temperature solutions. With this new mechanism, the scalars and the electromagnetic fields get attracted to temperature- and moduli-independent values at the north and south poles of the rotating black hole, although they vary along the Euclidean horizon in a non-universal way. Further, although the area and the spin of the black hole depend non-trivially on the temperature and on the moduli, the free energy is essentially a function only of the black hole charges (apart from a trivial dependence on the temperature and the moduli through the BPS mass), and agrees with the string theory index.
Nuclear and particle physics. Atomic energy. Radioactivity
About ten years ago, we established the first coronagraph that has been continuously operating on the high plateau of western China. This coronagraph is an internal occulting, 10 cm aperture instrument, installed at Lijiang Station through a collaboration with the Norikura Station of the National Astronomical Observatory of Japan. To ensure high efficiency in current and future coronal observations, developing integrated observation systems is essential for reliable, autonomous, and remote operation of coronagraphs. This paper introduces an advanced integrated observation and control system, based on the Lijiang 10 cm coronagraph. The coronagraph focuses on the observations for the solar inner corona, capturing the coronal green-line emission within a field range from <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.03</mn><msub><mi>R</mi><mo>⨀</mo></msub></mrow></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.5</mn><msub><mi>R</mi><mo>⨀</mo></msub></mrow></semantics></math></inline-formula>. To enhance the observational precision and efficiency, a comprehensive integrated system has been designed, incorporating various subsystems, including precise pointing and tracking mechanisms, a multi-band filter system, a protective dome system, and a robust data storage infrastructure. This paper details the hardware architecture and software frameworks supporting each subsystem. Results from extended operational testing confirm the stability of the system, its capacity for autonomous and remote observations, and significant improvements in the automation and efficiency of coronal imaging. The automated observation system will be further improved and used for our future coronagraphs to be developed for coronal magnetism diagnosis.
The Gaussian Industrial Source Complex Short Term 3 (ISCST3) model as applied to radon-222 emitted from tailings dams has not been properly validated for radon-222 dispersion modelling. In an attempt to validate the model, the concentrations of radon-222 and its progenies/daughters were measured at various points around a tailings dam. To verify that the measured radon-222 is from the tailings dam, a technique combining both gas and daughters ages with source apportionment method was developed. Model was validated by isolating radon-222 from different sources using the “age” of the gas approach and applying back trajectory calculations to identify the origin of the radon gas measured at points downwind. As predicted by the model, the origin of the radon emission was traced back to the tailings. The model was further validated by comparing measured data to model outputs and applying standard model validation statistics to validate and quantify the agreement between predicted and measured data. Model validation from statistical analysis showed a constant trend with minimum variability in the Index of Agreement (IOA), Normalized Mean Square Error (NMSE), and Fraction of Predictions method within a factor of two (FAC2) values. The analyses were based on the model prediction results over five days of measurements covering both morning and afternoon. There was an under prediction in the Fractional Bias (FB) and Geometric Mean bias (MG) in the afternoon of day 1. In addition, the model performed poorly in the afternoon of day 3.
Medical physics. Medical radiology. Nuclear medicine, Radioactivity and radioactive substances
Polarized beams are indispensable for many particle, atomic, and nuclear physics experiments where spin-dependent processes are to be studied. Currently, the primary sources of polarized electron beams, such as storage rings and polarized photo-cathodes, depend on radio-frequency (RF) technology, particularly for subsequent acceleration. As a result, they are characterized by their substantial size and limited availability. Unlike RF accelerators, the accelerating fields in Laser-Plasma-Accelerators (LPA) are not limited by material breakdown. LPAs can create beams of tens to hundreds of MeV in only a millimetre, which makes them a promising alternative to conventional accelerators. Compact polarized LPAs could help make polarized sources ubiquitous to facilitate many more polarized physics experiments. The LEAP (Laser Electron Acceleration with Polarization) project at DESY aims to generate and measure spin-polarized electron beams from a compact LPA for the first time. Spin-polarized electron beams can be generated from an LPA using a pre-polarized plasma source, where a circularly polarized UV laser pulse dissociates hydrogen halide molecules. Due to the expected beam energy of tens of MeVs, photon transmission polarimetry will be used for the subsequent polarization measurement in LEAP.
Neutron detection has significantly applied in security inspection and border control, high-energy physics, medical diagnostics, and nuclear monitoring. Recently, as one of the alternative materials, metal halide perovskites (MHPs) show great potential in high-performance neutron detector in both indirect and direct detecting mode. H or radioactive isotope, physically mixed, or atomic-level chemical hybrid into MHPs possesses large cross sections toward neutrons. The produced secondary particles induce MHPs generating high radioluminescence or detectable carriers. Accordingly, some advanced works about MHPs based neutron detectors were carried out and significant advancements led to unexpected and effective opportunities for the utilization of MHPs in the detection of neutrons. Herein, we aim at systematically summarizing current progress on MHPs based neutron detectors: (1) first, an introduction of background and detection mechanisms is provided to understand the neutron detectors clearly; (2) after that, we summarize the previously reported MHPs materials for neutron detecting and put an emphasis on the advanced work for various MHPs based neutron detectors; and (3) finally, the challenges remained and promising opportunities are also presented, for further boosting the performance of MHPs-based neutron detectors.
Chang-kyun Kim, Myoung S. Sohn, Kyungheum Kim
et al.
Over the past several decades, various types of accelerators have been installed and operated worldwide, mainly for nuclear research and radioisotope production. Among them, the cyclotron is a type of particle accelerator invented by Ernest O. Lawrence in the United States in 1934. It has been the best source of high-energy beams for nuclear physics experiments for the past several decades, and has been used to produce various radioisotopes used in diagnostic imaging such as positron emission tomography (PET) and single photon emission computed tomography (SPECT), as well as in brachytherapy and alpha particle therapy. However, cyclotrons are being dismantled and decommissioned domestically and internationally due to reaching their design life or due to aging, accidents, or other reasons, and there is no standardized technical or administrative procedure for this, so there is a growing need for standardization for safe decommissioning. Therefore, I will briefly review the activation assessment methods and procedures that should be given priority when ecommissioning various types of cyclotron facilities. In this study, I examined the general decommissioning procedures related to the radioactivity assessment that must precede a cyclotron facility producing PET radiotracers (C11, N13, O15, F18) used in medical institutions in Korea, and presented four methods to evaluate the radioactivity level: Monte Carlo computer simulation, γ spectroscopy, neutron fluence estimation by sampling, and profile analysis using concrete boring. In addition, I presented a radiation measurement method and procedure using a conversion factor as a general method to grasp the overall radioactivity status of a cyclotron prior to establishing a decommissioning plan.
Scattering probes the internal structure of quantum systems. We calculate the two-particle elastic scattering phase shift for a short-ranged interaction on a quantum computer. Short-ranged interactions with a large scattering length or shallow bound state describe a universality class that is of interest in atomic, condensed matter, nuclear, and particle physics. The phase shift is calculated by relating the ground state energy of the interacting particles in a harmonic trap. The relaxation method is used as the variational quantum eigensolver for the ground state calculation. Schmidt decomposition is used to reduce quantum circuits nominally requiring tens of qubits to 2-qubit circuits, thus reducing the noise in quantum measurements. Calculations in multi-particle systems with many-body interactions would benefit from this reduction of qubits in noisy quantum processors.
Isadora Veiga da Rosa, Janine Hastenteufel Dias, Rochelle Lykawka
et al.
Radiography is a crucial diagnostic imaging modality in clinical practice, with persistent challenges in digital radiography regarding the level of exposure. The International Electrotechnical Commission standardized the Exposure Index (EI) and Deviation Index (DI) in digital systems, aiming to improve the assessment of radiation exposure. Each exam has an associated Target Exposure Index (EIT), representing the balance between radiation dose and image quality. This study analyzed the EI and DI of digital radiographs at a university hospital, using a database of 71,760 radiographs. The analysis considered the action limits as suggested by the American Association of Physicists in Medicine (AAPM). The group of exposures carried out in radiography rooms presented a DI of 1.2, while that of exposures carried out on mobile equipment, 2.4. In contrast, the first group presented standard deviation values between 1.5 and 3.9, while the second, between 1.8 and 2.6. These results suggest that exposures performed using Automatic Exposure Control (CAE) differ less from EIT, however, radiographic techniques were more standardized among exams with mobile equipment, performed with manual selection of exposure parameters, as these exams presented a smaller DI dispersion range. The creation of an automated tool in Google Looker Studio facilitated interactive data analysis, presenting information by anatomical region and view, with the potential to continuously monitor radiological practices. For certain incidences, the average DI values obtained differed substantially from the ideal value, which requires optimization actions, investigation into the definition of adequate EIT and calibration of the CAE. The study provided a detailed overview of local radiographic practices, highlighting priorities for optimization and standardization actions.
Medical physics. Medical radiology. Nuclear medicine, Radioactivity and radioactive substances
We study the second-order scalar and density perturbations generated by Gaussian curvature perturbations and primordial gravitational waves in the radiation-dominated era. After presenting all the possible second-order source terms, we obtain the explicit expressions of the kernel functions and the power spectra of the second-order scalar perturbations. We show that the primordial gravitational waves might affect second-order energy density perturbation <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>δ</mi><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></msup><mo>=</mo><mi>δ</mi><msup><mi>ρ</mi><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></msup><mo>/</mo><msup><mi>ρ</mi><mrow><mo>(</mo><mn>0</mn><mo>)</mo></mrow></msup></mrow></semantics></math></inline-formula> significantly. The effects of primordial gravitational waves are studied in terms of different kinds of primordial power spectra.
Branched flow is an interesting phenomenon that can occur in diverse systems. It is usually linear in the sense that the flow does not alter the properties of the medium. Branched flow of light on thin films has recently been discovered. It is therefore of interest to know whether nonlinear light branching can also occur. Here, using particle-in-cell simulations, we find that in the case of an intense laser propagating through a randomly uneven medium, cascading local photoionization by the incident laser, together with the response of freed electrons in the strong laser fields, triggers space–time-dependent optical unevenness. The resulting branching pattern depends dramatically on the laser intensity. That is, the branching here is distinct from the existing linear ones. The observed branching properties agree well with theoretical analyses based on the Helmholtz equation. Nonlinear branched propagation of intense lasers potentially opens up a new area for laser–matter interaction and may be relevant to other branching phenomena of a nonlinear nature.
Nuclear and particle physics. Atomic energy. Radioactivity
A higher harmonic cavity (HHC) is popularly employed in synchrotron light storage rings to enhance the machine performance, which requires its fundamental mode resonant frequency to be tuned above the radio-frequency harmonic. However, this detuning is likely to cause Robinson instability. In this paper, we focus on a mode-zero Robinson instability driven by the fundamental mode of a passive superconducting harmonic cavity (PSHC). This instability oscillates slightly below the detuning frequency of PSHC and was recently observed in tracking simulations or experiments for several synchrotron light sources, but the underlying mechanisms have not been well understood. To investigate this instability, we modify the conventional Robinson instability equation with the inclusion of the damping effect. By solving directly this modified equation combined with performing macroparticle tracking simulation, it is found that this instability is largely dependent on the momentum compaction factor, the Q value and detuning of PSHC, and even the radiation damping time. Most importantly, this instability can be significantly enhanced by a higher Q of PSHC and a lower radiation damping time, which is completely contrary to the conventional Robinson instability.
Nuclear and particle physics. Atomic energy. Radioactivity
Alessio Pignalberi, Michael Pezzopane, Tommaso Alberti
et al.
In this work, we aim to characterize the effective scale height at the ionosphere F2-layer peak (<i>H</i><sub>0</sub>) by using in situ electron density (<i>N</i><sub>e</sub>) observations by Langmuir Probes (LPs) onboard the China Seismo-Electromagnetic Satellite (CSES—01). CSES—01 is a sun-synchronous satellite orbiting at an altitude of ~500 km, with descending and ascending nodes at ~14:00 local time (LT) and ~02:00 LT, respectively. Calibrated CSES—01 LPs <i>N</i><sub>e</sub> observations for the years 2019–2021 provide information in the topside ionosphere, whereas the International Reference Ionosphere model (IRI) provides <i>N</i><sub>e</sub> values at the F2-layer peak altitude for the same time and geographical coordinates as CSES—01. CSES—01 and IRI <i>N</i><sub>e</sub> datasets are used as anchor points to infer <i>H</i><sub>0</sub> by assuming a linear scale height in the topside representation given by the NeQuick model. COSMIC/FORMOSAT—3 (COSMIC—1) radio occultation (RO) data are used to constrain the vertical gradient of the effective scale height in the topside ionosphere in the linear approximation. With the CSES—01 dataset, we studied the global behavior of <i>H</i><sub>0</sub> for daytime (~14:00 LT) and nighttime (~02:00 LT) conditions, different seasons, and low solar activity. Results from CSES—01 observations are compared with those obtained through Swarm B satellite <i>N</i><sub>e</sub>-calibrated measurements and validated against those from COSMIC—1 RO for similar diurnal, seasonal, and solar activity conditions. <i>H</i><sub>0</sub> values modeled by using CSES—01 and Swarm B-calibrated observations during daytime both agree with corresponding values obtained directly from COSMIC—1 RO profiles. Differently, <i>H</i><sub>0</sub> modeling for nighttime conditions deserves further investigation because values obtained from both CSES—01 and Swarm B-calibrated observations show remarkable and spatially localized differences compared to those obtained through COSMIC—1. Most of the <i>H</i><sub>0</sub> mismodeling for nighttime conditions can probably to be attributed to a sub-optimal spatial representation of the F2-layer peak density made by the underlying IRI model. For comparison, <i>H</i><sub>0</sub> values obtained with non-calibrated CSES—01 and Swarm B <i>N</i><sub>e</sub> observations are also calculated and discussed. The methodology developed in this study for the topside effective scale height modeling turns out to be applicable not only to CSES—01 satellite data but to any in situ <i>N</i><sub>e</sub> observation by low-Earth-orbit satellites orbiting in the topside ionosphere.