We present a Gaussian mixture model of the projected multiple scattering angle over a large range of target thicknesses. The mixture model has two components describing the core and the tails of the ...distribution, respectively. It can be used as a fast algorithm for simulation purposes and with advanced methods of track reconstruction capable of coping with non-Gaussian noise. The exact multiple scattering distributions are obtained in a direct manner by repeated convolution of the single scattering distribution. The results are found to be compatible with the Molière approximation and with the standard formula of Highland, and give additional easy-to-use information about the tails of the distribution. Finally, the relative importance of hadronic elastic scattering as compared to multiple Coulomb scattering is evaluated.
The 'LiC Detector Toy' program Regler, M; Mitaroff, W; Valentan, M ...
Journal of physics. Conference series,
07/2008, Letnik:
119, Številka:
3
Journal Article
Recenzirano
Odprti dostop
LiC is a simple but powerful and flexible software tool, written in MatLab, for basic detector design studies (geometries, material budgets) by determining the resolution of reconstructed track ...parameters. It is based on a helix track model including multiple scattering, and consists of a simplified simulation of the detector followed by track reconstruction using the Kalman filter. After a short description of LiC's main characteristics, we demonstrate its capabilities by applying this tool in a performance study of the LDC and SiD detector concepts at the International Linear Collider (ILC).
Now thoroughly revised and up-dated, this indispensable guide describes techniques for handling and analysing large and complex data samples obtained from high-energy and nuclear physics experiments. ...It includes pattern recognition techniques to group measurements into physically meaningful objects like particle tracks and methods of extracting maximum information from available measurements.
AUSTRON and its notable new features Rauch, H.; Badurek, G.; Jericha, E. ...
Applied physics. A, Materials science & processing,
12/2002, Letnik:
74
Journal Article
In the reconstruction of particle tracks in high-energy physics experiments multiple scattering has to be taken into account by computing the variance of the deflection and of the lateral ...displacement of the track both for discrete and for continuous scatterers. We apply this method to modelling the lateral position uncertainty in the target area in the context of ion therapy. The beam monitoring unit is treated as a discrete scatterer, tissue and bones of the patient as a continuous scatterer. By a simple model of the energy dependence of the scattering process the variance of the lateral displacement can be written down in closed form.
By using just the variance of the lateral displacement it is not possible to describe the distribution in more detail, in particular the tails. If one wants to go beyond the Gaussian assumption, then it is convenient to model the distribution by a Gaussian mixture, in this case a mixture with only two components. One component describes the core of the distribution, the second one the tails. Starting from a thin scatterer, we compute the cumulants of the distribution in a scatterer of any thickness and show how to approximate it again by a Gaussian mixture with two components. We also show that under suitable assumptions the variance of the core reproduces very nicely the logarithmic correction formula which is usually applied to discard the tails in a Gaussian setting. In contrast, our approach yields a quantitative description of the tails which can then be used in the treatment planning for a fast and precise simulation of the effects of multiple scattering.
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► Exciton decay in carbon nanotubes is remotely controlled by surface acoustic waves. ► The electric fields associated with surface acoustic waves slow down exciton decay. ► The ...slowdown is caused by a decreased radiative rate due to a quadratic Stark effect. ► Remote-control could be of interest for device applications of carbon nanotubes.
We show that the photoluminescence intensity and decay dynamics of semiconducting single-walled carbon nanotube films can be remotely controlled by surface acoustic waves (SAW) launched on the piezoelectric substrate LiNbO3. Time-resolved measurements in the picosecond regime reveal that photoluminescence quenching results from a decrease of the radiative recombination rate by up to 25% for the accessible SAW amplitudes. The SAW-induced piezoelectric field acts as a quasi-static perturbation that polarizes the luminescent exciton state reducing the oscillator strength of the radiative transition following a quadratic field dependence. Surface acoustic waves could be used for the remote and contact-free electrical control of high-speed electronic and optoelectronic nanotube-based devices.
The Gluckstern formulas for the covariance matrix of track slope and curvature are generalized to circular tracks, with both plane and cylindrical detector surfaces. The formulas are extended to ...higher-order expansions of the track model and to the exact circular track model. An improved second-order formula is derived. Optimal detector spacings are obtained for minimal determinant of the covariance matrix and minimal variances of slope and curvature. The user interface to the MATLAB implementation of all formulas is described.
The first rules-of-thumb for the uncertainties in track momentum and direction of tracking detectors under inclusion of multiple scattering, as developed by Gluckstern Nucl. Instr. and Meth. 24 ...(1963) 381 in the times of the bubble chamber, were limited to tracks with low curvature and equidistant measurement points with equal accuracy. The extension to strongly curved tracks with nonvanishing incident angle, arbitrary detector configuration and accuracy was published recently M. Regler, R. Frühwirth, Nucl. Instr. and Meth. A 589 (2008) 109. However, this extension is restricted to the (symmetry) plane with tracks with zero dip angle, perpendicular to the magnetic field, and does not treat multiple scattering. The present study extends the analytical approximate formulas for the calculation of uncertainties in track momentum and direction of “barrel” detectors to non-zero dip angles, including multiple scattering. The dip angle dependence of all terms of the error matrix is calculated. The results of a comparison with a linear least-squares fit are presented, showing excellent agreement. An open source implementation of the exact covariance matrices is described.
The characteristic parameters of the present version of the planned AUSTRON neutron spallation source are: (a) 10
Hz repetition rate at the target, (b) 500
kW average beam power, (c) 1.6
GeV proton ...energy and (d) strongly dedicated to cold neutron research. The machine can be built based on existing techniques and would provide a performance gain between 3 and 10 compared to existing installations. Progress has been made in the planning of the instrumentation where an improved standard instrumentation and several new systems have been designed and evaluated by an international group of neutron scientists. A clean room area with vibration, temperature and humidity control provides new possibilities for neutron optics, neutron reflectometry and nuclear orientation experiments. A proposed magnetic focusing line with an active energy transfer system indicates the capability to achieve a further intensity gain by a factor of 10. The status of the ongoing internationalization process will be reported as well.
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