The momentum spectrum of cosmic ray muons above 300 GeV/c in the vertical direction

The sea-level vertical rauon momentum spectrum Has been measured in the momentum range 100 GeV/c to 3000 GeV/c, using the MARS spectrograph in Durham, The various instrumental effects which affect either the shape or the absolute intensity of the measured spectrum have been studied in detail. The analysis procedure has been discussed in detail including the accuracy of the analysis technique and the criteria for rejection of certain events. A simple muon production and propagation model has been used to predict the plon and kaon production spectra using the rauon spectrum derived from the results of this experiment. It has not been found possible to predict the ratio of the number of kaons to the number of pions produced at production and an estimate of this ratio (0.106) has been used to fit a constant exponent power law spectrum. The present results have been compared with those of other workers and are found to yield a smaller value of the exponent for the fitted power law production spectra. This result suggests that the pion and kaon production spectra are somewhat flatter than previously measured for momenta above 100 GeV/c by previous HAliS experiments(Ayre et al., 1975). The present results on the muon spectrum, however, ogree, within the limits of the statistical accuracy, with other spectrograph data. Comparison with surveys of indirect measurements of the aiuon momentum spectrum suggest that the present results give a higher absolute intensity for the muon momentum spectrum above 1000 3aV/c

Inverse-designed diamond photonics

Diamond hosts optically active color centers with great promise in quantum computation, networking, and sensing. Realization of such applications is contingent upon the integration of color centers into photonic circuits. However, current diamond quantum optics experiments are restricted to single devices and few quantum emitters because fabrication constraints limit device functionalities, thus precluding color center integrated photonic circuits. In this work, we utilize inverse design methods to overcome constraints of cutting-edge diamond nanofabrication methods and fabricate compact and robust diamond devices with unique specifications. Our design method leverages advanced optimization techniques to search the full parameter space for fabricable device designs. We experimentally demonstrate inverse-designed photonic free-space interfaces as well as their scalable integration with two vastly different devices: classical photonic crystal cavities and inverse-designed waveguide-splitters. The multi-device integration capability and performance of our inverse-designed diamond platform represents a critical advancement toward integrated diamond quantum optical circuits

Eddy current studies from the undulator-based positron source target wheel prototype

The ef­fi­cien­cy of fu­ture positron sources for the next gen­er­a­tion of high-en­er­gy par­ti­cle col­lid­ers (e.g. ILC, CLIC, LHeC) can be im­proved if the positron-pro­duc­tion tar­get is im­mersed in the mag­net­ic field of ad­ja­cent cap­ture op­tics. If the tar­get is also ro­tat­ing due to heat de­po­si­tion con­sid­er­a­tions then eddy cur­rents may be in­duced and lead to ad­di­tion­al heat­ing and stress­es. In this paper we pre­sent data from a ro­tat­ing tar­get wheel pro­to­type for the base­line ILC positron source. The wheel has been op­er­at­ed at rev­o­lu­tion rates up to 1800rpm in fields of the order of 1 Tesla. Com­par­isons are made be­tween torque data ob­tained from a trans­duc­er on the tar­get drive shaft and the re­sults of fi­nite-el­e­ment sim­u­la­tions. Ro­tor­dy­nam­ics is­sues are pre­sent­ed and fu­ture ex­per­i­ments on other as­pects of the positron source tar­get sta­tion are con­sid­ered

The study of the influence of Jahn-Teller coupling and low symmetry strain on the anomalous electron paramagnetic resonance spectrum of titanium(lll) doped CsAl(SO4)2·12H2O

The controversial EPR spectrum of titanium(III) as an impurity in cesium aluminum sulphate alum has been re-examined using conventional CW- and a novel pulsed-EPR technique, which monitors the nutation frequency as a function of field. The CW-spectra display a high degree of structure, which is interpreted as arising from chemically distinct titanium(III) species. The two-dimensional nutation spectrum maps the g vs g relation from just one crystal orientation, and to far greater precision than available from CW-EPR. This novel technique shows that the origin of the linewidths observed for some of the EPR lines is inhomogeneous broadening, the nature of which can be described adequately only in the two-dimensional nutation spectrum. Calculations of g vs g have been undertaken by numerical diagonalization of the vibronic Hamiltonian. It is found that the relationship between g and g can be modeled only by assuming that the titanium(III) ions are subject to both dynamic Jahn-Teller coupling and low symmetry strain. Furthermore, it is shown that the calculated g vs g relation is strongly dependent upon the nature of the vibronic interaction assumed. An excellent reproduction of the experimental data is obtained, using parameters consistent with those employed to model the susceptibility data of the isostructural cesium titanium sulphate alum

Fast Prediction of HCCI and PCCI Combustion with an Artificial Neural Network-Based Chemical Kinetic Model

We have added the capability to look at in-cylinder fuel distributions using a previously developed ignition model within a fluid mechanics code (KIVA3V) that uses an artificial neural network (ANN) to predict ignition (The combined code: KIVA3V-ANN). KIVA3V-ANN was originally developed and validated for analysis of Homogeneous Charge Compression Ignition (HCCI) combustion, but it is also applicable to the more difficult problem of Premixed Charge Compression Ignition (PCCI) combustion. PCCI combustion refers to cases where combustion occurs as a nonmixing controlled, chemical kinetics dominated, autoignition process, where the fuel, air, and residual gas mixtures are not necessarily as homogeneous as in HCCI combustion. This paper analyzes the effects of introducing charge non-uniformity into a KIVA3V-ANN simulation. The results are compared to experimental results, as well as simulation results using a more physically representative and computationally intensive code (KIVA3V-MPI-MZ), which links a fluid mechanics code to a multi-zone detailed chemical kinetics solver. The results indicate that KIVA3V-ANN produces reasonable approximations to the more accurate KIVA3V-MPI-MZ at a much reduced computational cost

Walking the walk: a phenomenological study of long distance walking

Evidence suggests that regular walking can elicit significant psychological benefits although little evidence exists concerning long distance walking. The purpose of this study was to provide detailed accounts of the experiences of long distance walkers. Phenomenological interviews were conducted with six long distance walkers. Data were transcribed verbatim before researchers independently analyzed the transcripts. Participants reported a cumulative effect with positive feelings increasing throughout the duration of the walk. Long distance walking elicited positive emotions, reduced the effects of life-stress, and promoted an increased sense of well-being and personal growth. Results are aligned to theories and concepts from positive psychology