We have built and commissioned a novel standalone multi-crystal x-ray spectrometer (MOSARIX) in the von Hamos configuration based on highly annealed pyrolytic graphite crystals. The spectrometer is optimized for the energy range of 2-5 keV, but this range can be extended up to 20 keV by using higher reflection orders. With its nine crystals and a Pilatus detector, MOSARIX achieves exceptional detection efficiency with good resolving power (better than 4000), opening the door to study small cross section phenomena and perform fast in situ measurements.
View Article and Find Full Text PDFFragmentation dynamics of core-excited isolated ammonia molecules is studied by two different and complementary experimental methods, high-resolution resonant Auger spectroscopy and electron energy-selected Auger electron-photoion coincidence spectroscopy (AEPICO). The combined use of these two techniques allows obtaining information on different dissociation patterns, in particular fragmentation before relaxation, often called ultrafast dissociation (UFD), and fragmentation after relaxation. The resonant Auger spectra contain the spectral signature of both molecular and fragment final states, and therefore can provide information on all events occurring during the core-hole lifetime, in particular fragmentation before relaxation.
View Article and Find Full Text PDFWe study vibrationally-resolved resonant Auger (RAS) spectra of ammonia recorded in coincidence with the NH fragment, which is produced in the course of dissociation either in the core-excited 1s4a11 intermediate state or the first spectator 3a4a11 final state. Correlation of the NH ion flight times with electron kinetic energies allows directly observing the Auger-Doppler dispersion for each vibrational state of the fragment. The median distribution of the kinetic energy release , derived from the coincidence data, shows three distinct branches as a function of Auger electron kinetic energy : + 1.
View Article and Find Full Text PDFBackground: The bite of Triatominae can cause cutaneous allergic reactions and even anaphylaxis. Since the early 1980s, no population-based surveys have been done in Southern California, and none was ever carried out in inland Los Angeles or Riverside Counties.
Objectives: To measure the frequency of insect sightings, bites and allergic reactions in a suburban area of eastern Los Angeles County and along with rural and urban sites in Riverside County.