971 research outputs found
Electrode thickness measurement of a Si(Li) detector for the SIXA array
Cathode electrodes of the Si(Li) detector elements of the SIXA X-ray
spectrometer array are formed by gold-palladium alloy contact layers. The
equivalent thickness of gold in one element was measured by observing the
characteristic L-shell X-rays of gold excited by monochromatised synchrotron
radiation with photon energies above the L3 absorption edge of gold. The
results obtained at 4 different photon energies below the L2 edge yield an
average value of 22.4(35) nm which is consistent with the earlier result
extracted from detection efficiency measurements.
PACS: 29.40.Wk; 85.30.De; 07.85.Nc; 95.55.Ka
Keywords: Si(Li) detectors, X-ray spectrometers, X-ray fluorescence, detector
calibration, gold electrodes, synchrotron radiationComment: 10 pages, 4 PostScript figures, uses elsart.sty, submitted to Nucl.
Instrum. Meth.
Characterising a Si(Li) detector element for the SIXA X-ray spectrometer
The detection efficiency and response function of a Si(Li) detector element
for the SIXA spectrometer have been determined in the 500 eV to 5 keV energy
range using synchrotron radiation emitted at a bending magnet of the electron
storage ring BESSY, which is a primary radiation standard. The agreement
between the measured spectrum and the model calculation is better than 2%.
PACS: 95.55.Ka; 07.85.Nc; 29.40.Wk; 85.30.De
Keywords: Si(Li) detectors, X-ray spectrometers, detector calibration, X-ray
response, spectral lineshapeComment: 11 pages, 11 PostScript figures, uses elsart.sty, submitted to Nucl.
Instrum. Meth.
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
Placenta previa percreta left in situ - management by delayed hysterectomy: a case report
<p>Abstract</p> <p>Introduction</p> <p>Placenta percreta is an obstetric emergency often associated with massive hemorrhage and emergency hysterectomy.</p> <p>Case presentation</p> <p>We present the case of a 30-year-old African woman, gravida 7, para 5, with placenta percreta managed by an alternative approach: the placenta was left <it>in situ</it>, methotrexate was administered, and a delayed hysterectomy was successfully performed.</p> <p>Conclusions</p> <p>Further studies are needed to develop the most appropriate management option for the most severe cases of abnormal placentation. Delayed hysterectomy may be a reasonable strategy in the most severe cases.</p
Vacuum Rabi splitting and strong coupling dynamics for surface plasmon polaritons and Rhodamine 6G molecules
We report on strong coupling between surface plasmon polaritons (SPP) and
Rhodamine 6G (R6G) molecules, with double vacuum Rabi splitting energies up to
230 and 110 meV. In addition, we demonstrate the emission of all three energy
branches of the strongly coupled SPP-exciton hybrid system, revealing features
of system dynamics that are not visible in conventional reflectometry. Finally,
in analogy to tunable-Q microcavities, we show that the Rabi splitting can be
controlled by adjusting the interaction time between waveguided SPPs and R6G
deposited on top of the waveguide. The interaction time can be controlled with
sub-fs precision by adjusting the length of the R6G area with standard
lithography methods.Comment: 4 pages, 4 figure
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