40 research outputs found
Data compression for the Cassini radio and plasma wave instrument
The Cassini Radio and Plasma Wave Science experiment will employ data compression to make effective use of the available data telemetry bandwidth. Some compression will be achieved by use of a lossless data compression chip and some by software in a dedicated 80C85 processor. A description of the instrument and data compression system are included in this report. Also, the selection of data compression systems and acceptability of data degradation is addressed
Determination of the dispersion of low frequency waves downstream of a quasiperpendicular collisionless shock
International audienceA method of wave mode determination, which was announced in Balikhin and Gedalin, is applied to AMPTE UKS and AMPTE IRM magnetic field measurements downstream of supercritical quasiperpendicular shock. The method is based on the fact that the relation between phase difference of the waves measured by two satellites, Doppler shift equation, the direction of the wave propagation are enough to obtain the dispersion equation of the observed waves. It is shown that the low frequency turbulence mainly consists of waves observed below 1 Hz with a linear dependence between the absolute value of wave vector |k| and the plasma frame wave frequency. The phase velocity of these waves is close to the phase velocity of intermediate waves Vint = Vacos(?)
Determination of the dispersion of low frequency waves downstream of a quasiperpendicular collisionless shock
Radiation Hardness Studies in a CCD with High-Speed Column Parallel Readout
Charge Coupled Devices (CCDs) have been successfully used in several high
energy physics experiments over the past two decades. Their high spatial
resolution and thin sensitive layers make them an excellent tool for studying
short-lived particles. The Linear Collider Flavour Identification (LCFI)
collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex
detector of the International Linear Collider (ILC). The CPCCDs can be read out
many times faster than standard CCDs, significantly increasing their operating
speed. The results of detailed simulations of the charge transfer inefficiency
(CTI) of a prototype CPCCD are reported and studies of the influence of gate
voltage on the CTI described. The effects of bulk radiation damage on the CTI
of a CPCCD are studied by simulating the effects of two electron trap levels,
0.17 and 0.44 eV, at different concentrations and operating temperatures. The
dependence of the CTI on different occupancy levels (percentage of hit pixels)
and readout frequencies is also studied. The optimal operating temperature for
the CPCCD, where the effects of the charge trapping are at a minimum, is found
to be about 230 K for the range of readout speeds proposed for the ILC. The
results of the full simulation have been compared with a simple analytic model.Comment: 3 pages, 6 figures; presented at IEEE'07, ALCPG'07, ICATPP'0
The Validity of Using Analogue Patients in Practitioner–Patient Communication Research: Systematic Review and Meta-Analysis
Determination of the dispersion of low frequency waves downstream of a quasiperpendicular collisionless shock
A method of wave mode determination, which
was announced in Balikhin and Gedalin, is applied to AMPTE UKS and AMPTE IRM
magnetic field measurements downstream of supercritical quasiperpendicular
shock. The method is based on the fact that the relation between phase
difference of the waves measured by two satellites, Doppler shift equation, the
direction of the wave propagation are enough to obtain the dispersion equation
of the observed waves. It is shown that the low frequency turbulence mainly
consists of waves observed below 1 Hz with a linear dependence between the
absolute value of wave vector |k| and the plasma frame
wave frequency. The phase velocity of these waves is close to the phase velocity
of intermediate waves Vint = Vacos(θ)
Elastic scattering and fusion of 9Be+208Pb: Density function dependence of the double folding renormalization
Elastic scattering angular distributions of the weakly bound 9Be projectile from 208Pb have been measured for 11 beam energies ranging from 38 to 75 MeV . Analysis was carried out with the optical model, employing a double folded microscopic real potential with four different 9Be density functions. The surface strengths of the interaction potentials were consistent and all exhibited a threshold anomaly. However, the renormalization factor required to obtain an optimum fit to the data varied significantly depending upon which 9Be density function was used, cautioning that conclusions about the effect of breakup should not be based solely upon the value of this factor. Fusion cross sections predicted from these potentials were extracted using a barrier penetration model. Comparison with recently published experimental data suggests that the flux removed from complete fusion by breakup is balanced by the flux redirected into the partial fusion channel