The Fermilab Proton-Improvement-Plan-II (PIP-II) is being implemented in order to support the precision neutrino oscillation measurements at the Deep Underground Neutrino Experiment, the U.S. ...flagship neutrino experiment. The PIP-II LINAC is presently under construction and is expected to provide 800~MeV protons with 2~mA current. This white paper summarizes the outcome of the first workshop on May 10 through 13, 2023, to exploit this capability for new physics opportunities in the kinematic regime that are unavailable to other facilities, in particular a potential beam dump facility implemented at the end of the LINAC. Various new physics opportunities have been discussed in a wide range of kinematic regime, from eV scale to keV and MeV. We also emphasize that the timely establishment of the beam dump facility at Fermilab is essential to exploit these new physics opportunities.
A portable monoenergetic 24 keV neutron source based on the \(^{124}\)Sb-\(^9\)Be photoneutron reaction and an iron filter has been constructed and characterized. The coincidence of the neutron ...energy from SbBe and the low interaction cross-section with iron (mean free path up to 29 cm) makes pure iron specially suited to shield against gamma rays from \(^{124}\)Sb decays while letting through the neutrons. To increase the \(^{124}\)Sb activity and thus the neutron flux, a \(>\)1 GBq \(^{124}\)Sb source was produced by irradiating a natural Sb metal pellet with a high flux of thermal neutrons in a nuclear reactor. The design of the source shielding structure makes for easy transportation and deployment. A hydrogen gas proportional counter is used to characterize the neutrons emitted by the source and a NaI detector is used for gamma background characterization. At the exit opening of the neutron beam, the characterization determined the neutron flux in the energy range 20-25 keV to be 5.36\(\pm\)0.20 neutrons per cm\(^2\) per second and the total gamma flux to be 213\(\pm\)6 gammas per cm\(^2\) per second (numbers scaled to 1 GBq activity of the \(^{124}\)Sb source). A liquid scintillator detector is demonstrated to be sensitive to neutrons with incident kinetic energies from 8 to 17 keV, so it can be paired with the source as a backing detector for neutron scattering calibration experiments. This photoneutron source provides a good tool for in-situ low energy nuclear recoil calibration for dark matter experiments and coherent elastic neutrino-nucleus scattering experiments.
A waveguide model for spectral analysis of finite composite structures based on higher-order shear deformation theory (HSDT) is reported in this paper. The advantages of using the proposed model are ...attributed to the following: (1) the displacement field interpolation is carried out using the basis vector from the null space of the characteristic system, and this numerical step is a bi-product of the usual wave dispersion analysis in frequency domain, (2) the standard finite element discretization procedure involving nodal variables is employed, (3) both the frequency response and the time domain response can be obtained with the help of fast Fourier transformation (FFT) algorithm and (4) no constraint in terms of low or high frequencies is imposed, except that for a prescribed frequency band of excitation the assumed field needs to be consistent with the geometric scales in the composite material system. A novel method of embedding functionally graded array of dissimilar material phases, periodic or aperiodic, in the finite element dynamic stiffness matrix is presented, where the homogenized properties of the material system in the smallest wavelength scale can be used. Numerical simulations under impact type loading are carried out to study the effect of frequency band of excitation on the velocity response of homogeneous and inhomogeneous beam type structures.
A multi-layer perceptron (MLP) network using error back propagation algorithm is employed in this paper to estimate the damage parameters from broad-band spectral data as diagnostic signal. Various ...existing models of damage in laminated composite and the resulting stiffness degradation are discussed from comparative view-point. Degradation of ply properties can be considered to be one of the damage model parameters while monitoring transverse matrix cracks in cross-ply, splitting in longitudinal ply, and evolution of consecutive stages of damage, such as delaminations and fiber fracture. The stiffness degradation factor, the location and size of the damaged zone in laminated composite beam are considered as damage model parameters in the present paper. Fourier spectral data, which is typical to most of the diagnostic wave measurements, are used as input to the neural network. Since, training the neural network in such case involves many data sets and all of these data are difficult to generate using experiments, a spectral finite element model (SFEM) with embedded degraded zone in laminated composite beam is developed. Numerical simulation using this element is carried out, which shows the nature of temporal signal that are likely to be measured. Analytical studies on the performance of the neural network are presented based on numerically simulated data. Effect of measurement noise on the network performance is also reported.
Layer assignment for crosstalk risk minimization Di Wu; Jiang Hu; Mahapatra, R. ...
ASP-DAC 2004: Asia and South Pacific Design Automation Conference 2004 (IEEE Cat. No.04EX753),
2004
Conference Proceeding
In ultra-deep submicron technology, crosstalk noise is so severe that crosstalk avoidance merely in detailed routing is not adequate and it has to be considered in earlier design stages. We propose ...two heuristics for crosstalk mitigation in layer assignment, which is a stage between global routing and detailed routing, so that subsequent crosstalk avoidance in detailed routing can be more attainable. The predetailed-routing crosstalk is estimated through a probabilistic model. The constraint on the amount of vias is also considered. Experimental results on benchmark circuits confirm the effectiveness of the proposed heuristics.
We show results from the Coherent CAPTAIN Mills (CCM) 2019 engineering run which begin to constrain regions of parameter space for axion-like particles (ALPs) produced in electromagnetic particle ...showers in an 800 MeV proton beam dump, and further investigate the sensitivity of ongoing data-taking campaigns for the CCM200 upgraded detector. Based on beam-on background estimates from the engineering run, we make realistic extrapolations for background reduction based on expected shielding improvements, reduced beam width, and analysis-based techniques for background rejection. We obtain reach projections for two classes of signatures; ALPs coupled primarily to photons can be produced in the tungsten target via the Primakoff process, and then produce a gamma-ray signal in the Liquid Argon (LAr) CCM detector either via inverse Primakoff scattering or decay to a photon pair. ALPs with significant electron couplings have several additional production mechanisms (Compton scattering, \(e^+e^-\) annihilation, ALP-bremsstrahlung) and detection modes (inverse Compton scattering, external \(e^+e^-\) pair conversion, and decay to \(e^+e^-\)). In some regions, the constraint is marginally better than both astrophysical and terrestrial constraints. With the beginning of a three year run, CCM will be more sensitive to this parameter space by up to an order of magnitude for both ALP-photon and ALP-electron couplings. The CCM experiment will also have sensitivity to well-motivated parameter space of QCD axion models. It is only a recent realization that accelerator-based large volume liquid argon detectors designed for low energy coherent neutrino and dark matter scattering searches are also ideal for probing ALPs in the unexplored \(\sim\)MeV mass scale.
In this work, we investigate the performance of cooperative spectral sensing, where each OFDM-based CR is equipped with multiple-antennas and uses SLC based energy detector to detect the presence of ...PU signal within its communication range. Using this approach, the CR can detect the spectrum hole with subcarrier resolution. The simulation results suggest that a trade-off is necessary between detection probability, observation length, number of antennas and cooperating user at a particular value of false-alarm probability and SNR.
Every day, thousands of people in the United States receive polycyclic antidepressants (PCAs) prescribed by their primary care physicians. We have examined the cardiovascular manifestations of ...polycyclic antidepressants in 14 patients with primary depression receiving various antidepressant drugs for a period of six months or more. None had suffered from any systemic illness. All 14 received a commonly prescribed PCA, such as doxepin, amitriptyline, imipramine, desipramine or amoxapine, in therapeutic doses. None developed any significant adverse reaction. Left ventricular function, as determined by M-mode echocardiogram, was within normal limit in all patients. A twenty-four-hour ambulatory electrocardiogram revealed rare supraventricular ectopic beats in 8 patients and ventricular ectopic activity (Lown grade 1) in 4 patients. In 1 patient, who received additional lithium carbonate for treatment of depression, both supraventricular and ventricular ectopic activity developed on rare occasions. In 4 of the 8 patients the plasma concentration of PCA was optimal or near optimal, and in 4 of the 8 patients it was subtherapeutic (even though these 4 patients had shown clinical improvement with continued polycyclic therapy). It appears from the present data that antidepressant therapy with PCAs prescribed in therapeutic doses was well tolerated, without any significant adverse cardiovascular reaction, in otherwise healthy young patients with primary depression.
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