Search results for "libration"
showing 10 items of 901 documents
A 16 channel high resolution (<11 ps RMS) Time-to-Digital Converter in a Field Programmable Gate Array
2012
A 16-channel Time-to-Digital Converter (TDC) was implemented in a general purpose Field-Programmable Gate Array (FPGA). The fine time calculations are achieved by using the dedicated carry-chain lines. The coarse counter defines the coarse time stamp. In order to overcome the negative effects of temperature and power supply dependency bin-by-bin calibration is applied. The time interval measurements are done using 2 channels. The time resolution of channels are calculated for 1 clock cycle and a minimum of 10.3 ps RMS on two channels, yielding 7.3 ps RMS (10.3 ps/√2) on a single channel is achieved.
The Heliospheric Imagers Onboard the STEREO Mission
2008
Mounted on the sides of two widely separated spacecraft, the two Heliospheric Imager (HI) instruments onboard NASA’s STEREO mission view, for the first time, the space between the Sun and Earth. These instruments are wide-angle visible-light imagers that incorporate sufficient baffling to eliminate scattered light to the extent that the passage of solar coronal mass ejections (CMEs) through the heliosphere can be detected. Each HI instrument comprises two cameras, HI-1 and HI-2, which have 20° and 70° fields of view and are off-pointed from the Sun direction by 14.0° and 53.7°, respectively, with their optical axes aligned in the ecliptic plane. This arrangement provides coverage over solar…
Calibration and Simulation of the GRB trigger detector of the Ultra Fast Flash Observatory
2013
The UFFO (Ultra-Fast Flash Observatory) is a GRB detector on board the Lomonosov satellite, to be launched in 2013. The GRB trigger is provided by an X-ray detector, called UBAT (UFFO Burst Alarm & Trigger Telescope), which detects X-rays from the GRB and then triggers to determine the direction of the GRB and then alerts the Slewing Mirror Telescope (SMT) to turn in the direction of the GRB and record the optical photon fluxes. This report details the calibration of the two components: the MAPMTs and the YSO crystals and simulations of the UBAT. The results shows that this design can observe a GRB within a field of view of ±35° and can trigger in a time scale as short as 0.2 – 1.0 s af…
Study and implementation of a soft X-ray 100 eV -20 keV fixed exit monochromator system
2006
We describe a “built in house” X-ray monochromator which produces a fixed exit X-ray beam tunable in the full energy range 0.1 - 20 keV. The system is based on a double diffraction on two large size parallel crystals positioned using a remotely controlled micropositioning system in order to keep the position of the monochromatic beam for any chosen energy. Up to six different diffracting elements can be selected without breaking the vacuum. This allows to cover the full energy range of interest. The system is part of an upgrading project of the XACT facility at the Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Palermo G.S. Vaiana, and will be employed for the testing and c…
Monitoring the stability of thin and medium back-up filters of the Newton-XMM EPIC camera
2003
We are conducting a measurement program on back-up filters of the XMM-Newton EPIC camera aimed at monitoring possible aging effects during the mission lifetime. One thin and one medium EPIC back-up filters have been stored since 1997 in an environment similar to that one of the flight filters (dry nitrogen box before launch, high vacuum after launch). The transmission of the two filters has been measured periodically in the 1900-10000 angstrom wavelength range where effects of aging would be clearly evident. The preliminary results, after 5 years of monitoring, show that a slight aging effect has occurred on both filters which, however, has no significant impact onto the EPIC calibration fo…
Calibration campaign of the Borexino detector for the search of sterile neutrinos with SOX
2020
Abstract The SOX (Short distance Oscillations with boreXino) experiment aims to investigate possible anomalous oscillatory behaviours in neutrinos, including the existence of sterile neutrinos, by exploiting the very low radioactive background of the Borexino detector. A calibration campaign is crucial to achieve a deeper understanding of the energy response and the spatial reconstruction accuracies of the detector. It will be performed with a suite of low-activity radioactive sources which will map the whole active volume, especially nearby the inner vessel. The calibration points at the border of the active zones will be extremely important to study the neutron detection efficiency. The c…
RGB Photoelasticity: Review and Improvements
2010
: This paper considers the main developments of RGB photoelasticity with reference to the maximum measurable retardation. In this paper, a new procedure based on the standard error function evaluated on a subset of the calibration array is also proposed and experimentally tested. The experiments show that the filament lamp makes it possible to find retardations until approximately 4 fringe orders while the fluorescent lamp makes it possible to determine higher fringe orders (12 fringe orders in this paper) owing to the discrete spectrum of the source. The paper shows that, by using the incandescent lamp, the primary limiting factor is the lack of modulation of the R, G and B signals wherea…
The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
2000
The EPIC focal plane imaging spectrometers on XMM-Newton use CCDs to record the images and spectra of celestial X-ray sources focused by the three X-ray mirrors. There is one camera at the focus of each mirror; two of the cameras contain seven MOS CCDs, while the third uses twelve PN CCDs, defining a circular field of view of 30 arcmin diameter in each case. The CCDs were specially developed for EPIC, and combine high quality imaging with spectral resolution close to the Fano limit. A filter wheel carrying three kinds of X-ray transparent light blocking filter, a fully closed, and a fully open position, is fitted to each EPIC instrument. The CCDs are cooled passively and are under full clos…
JEM–X inflight performance
2003
We summarize the inflight performance of JEM-X, the X-ray monitor on the INTEGRAL mission during the initial ten months of operations. The JEM-X instruments have now been tuned to stable operational conditions. The performance is found to be close to the pre-launch expectations. The ground calibrations and the inflight calibration data permit to determine the instruments characteristics to fully support the scientific data analysis. Reglero Velasco, Victor, Victor.Reglero@uv.es ; Martinez Nuñez, Silvia, Silvia.Martinez@uv.es
Precision measurements of the charge radii of potassium isotopes
2019
International audience; Precision nuclear charge radii measurements in the light-mass region are essential for understanding the evolution of nuclear structure, but their measurement represents a great challenge for experimental techniques. At the Collinear Resonance Ionization Spectroscopy (CRIS) setup at ISOLDE-CERN, a laser frequency calibration and monitoring system was installed and commissioned through the hyperfine spectra measurement of $^{38–47}$K. It allowed for the extraction of the hyperfine parameters and isotope shifts with better than 1 MHz precision. These results are in excellent agreement with available literature values and they demonstrate the suitability of the CRIS tec…