Mathematical modelling in measurement and instrumentation

This paper presents a brief outline of the use of mathematical modelling techniques in measurement and instrumentation systems and sub-systems. Following an overview of various models, it illustrates some of the recent advances in mathematical modelling of sensors and instrument transducers. This is illustrated in two case studies describing the use of numerical finite element (FE) modelling techniques for CAD and performance modelling of capacitive sensors and torque motor actuators

Design and tests of the hard X-ray polarimeter X-Calibur

X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOCuS grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10-80 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.Comment: 9 pages, 5 figures, conference proceedings: SPIE 2011 (San Diego

Cosmic Ray Abundances of Sn, Te, Xe, and Ba Nuclei Measured on HEAO 3

Elements with even atomic number ( Z) in the interval 50 ~ Z ~ 56 have been resolved in the cosmic radiation using the Heavy Nuclei Experiment on the HEAO 3 satellite. The observation that 50Sn and 56Ba are more abundant than 52Te Elements with even atomic number ( Z) in the interval 50 ~ Z ~ 56 have been resolved in the cosmic radiation using the Heavy Nuclei Experiment on the HEAO 3 satellite. The observation that 50Sn and 56Ba are more abundant than 52Te and 54Xe is inconsistent with a purer-process cosmic-ray source. Adjustment of source abundances for an enhancement of those elements with a low first ionization potential does not change this conclusion and 54Xe is inconsistent with a purer-process cosmic-ray source. Adjustment of source abundances for an enhancement of those elements with a low first ionization potential does not change this conclusion

Implications of Ultraheavy Cosmic-Ray Source Composition Derived from Observations by the HEAO-3 Heavy Nuclei Experiment

We have derived the contribution of r-process and s-process nucleosynthesis to the Cameron (1980) solar system (SS) abundances for Z~33. In the interval 34 ~Zs; 40 our HEA0-3 data extrapolated to the cosmic-ray source (CRS) fit the solar system mix better than r-process. In the interval 26 < Z < 40 the HEA0-3 results for CRS/SS follow the same general correlation with first ionization potential as for the lighter eiements although there are deviations in detail

Abundances of Cosmic Ray Nuclei for 26 ≤ Z ≤ 40 From HEAO-3 Heavy Nuclei Experiment

Individual elements in the cosmic radiation of even atomic number (Z)in the interval 26≤ Z ≤ 40 have been resolved and their relative abundances measured. The results are inconsistent with a cosmic-ray source whose composition in this charge interval is dominated by r-process nucleosynthesis

Galactic Cosmic Ray Origins and OB Associations: Evidence from SuperTIGER Observations of Elements 26_{26}Fe through 40_{40}Zr

We report abundances of elements from $_{26}$Fe to $_{40}$Zr in the cosmic radiation measured by the SuperTIGER (Trans-Iron Galactic Element Recorder) instrument during 55 days of exposure on a long-duration balloon flight over Antarctica. These observations resolve elemental abundances in this charge range with single-element resolution and good statistics. These results support a model of cosmic-ray origin in which the source material consists of a mixture of 19$^{+11}_{-6}$\% material from massive stars and $\sim$81\% normal interstellar medium (ISM) material with solar system abundances. The results also show a preferential acceleration of refractory elements (found in interstellar dust grains) by a factor of $\sim$4 over volatile elements (found in interstellar gas) ordered by atomic mass (A). Both the refractory and volatile elements show a mass-dependent enhancement with similar slopes.Comment: 9 pages, 12 figures, 2 tables, accepted by Ap

Cosmic-ray abundances of elements with atomic number 26 ≤ Z ≤ 40 measured on HEAO 3

Individual elements in the cosmic radiation of even atomic number (Z) in the interval 26 ≤ Z ≤ 40 have been resolved and their relative abundances measured. The results are inconsistent with a cosmic-ray source whose composition in this charge interval is dominated by r-process nucleosynthests. The ratios of cosmic-ray source abundances to solar system abundances in this interval follow the same general correlation with first ionization potential as for the lighter elements although there are deviations in detail

Energy Spectra of Ultraheavy Cosmic Rays Results from HEAO-3

The HEAO-3 Heavy Nuclei Experiment measures cosmic-ray energy directly in the interval 400 to ~1200 MeV/amu. Geomagnetic cutoffs can also be derived up to ~15 GV. We present preliminary rigidity spectra of various ultraheavy cosmic-ray elements relative to iron

The Non-Z^2 Response of the Heavy Nuclei Cosmic Ray Detector on HEAO-3

A combination of ion chambers and Cerenkov radiators similar to the Heavy Nuclei Experiment flown on HEAO-3 was calibrated at the Bevalac heavy-ion accelerator using beams of Mn-25 nuclei at kinetic energies up to about 1700 MeV/nucleon and Au-79 nuclei up to about 1000 MeV/nucleon. The data show only a small deviation (about 2-3 charge units at Au) from the Z^2 scaling used previously (Binns et al., 1981, 1982, 1983) to analyze the HNE data. Although at lower energy, the calibration indicates that the published relative abundances of the _(50)Sn/_(56)Ba group and the published upper-limit actinide abundances are not likely to be significantly affected by non-Z^2 effects