8 research outputs found
Efficient picosecond x-ray pulse generation from plasmas in the radiation dominated regime
No full textThe efficient conversion of optical laser light into bright ultrafast x-ray pulses in laser created plasmas is of high interest for dense plasma physics studies, material science, and other fields. However, the rapid hydrodynamic expansion that cools hot plasmas has limited the x-ray conversion efficiency (CE) to 1% or less. Here we demonstrate more than one order of magnitude increase in picosecond x-ray CE by tailoring near solid density plasmas to achieve a large radiative to hydrodynamic energy loss rate ratio, leading into a radiation loss dominated plasma regime. A record 20% CE into ℎ>1 keVhν>1 keV photons was measured in arrays of large aspect ratio Au nanowires heated to keV temperatures with ultrahigh contrast femtosecond laser pulses of relativistic intensity. The potential of these bright ultrafast x-ray point sources for table-top imaging is illustrated with single shot flash radiographs obtained using low laser pulse energy. These results will enable the deployment of brighter laser driven x-ray sources at both compact and large laser facilities.Fil: Hollinger, Reed. Department Of Electrical And Engineering;Fil: Bargsten, Clayton. Department Of Electrical And Engineering;Fil: Shlyaptsev, Vyacheslav N.. Department Of Electrical And Engineering;Fil: Kaymak, Vural. Institut Fur Theoretische Physik, Heinrich-heine-univer;Fil: Pukhov, Alexander. Heinrich-heine-universität Düsseldorf;Fil: Capeluto, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Wang, Shoujun. Department Of Electrical And Engineering;Fil: Rockwood, Alex. Department Of Electrical And Engineering;Fil: Wang, Yong. Department Of Electrical And Engineering;Fil: Townsend, Amanda. Department Of Electrical And Engineering;Fil: Prieto, Amy. Department Of Electrical And Engineering;Fil: Stockton, Patrick. Department Of Electrical And Engineering;Fil: Curtis, Alden. Department Of Electrical And Engineering;Fil: Rocca, Jorge J.. Department Of Electrical And Engineering
Compact gain-saturated x-ray lasers down to 6.85 nm and amplification down to 5.85 nm
No full textPlasma-based x-ray lasers allow single-shot nano-scale imaging and other experiments requiring a large number of photons per pulse to be conducted in compact facilities. However, compact repetitively fired gain-saturated x-ray lasers have been limited to wavelengths above λ = 8.85 nm. Here we extend their range to λ = 6.85 nm by transient traveling wave excitation of Ni-like Gd ions in a plasma created with an optimized pre-pulse followed by rapid heating with an intense sub-picosecond pump pulse. Isoelectronic scaling also produced strong lasing at 6.67 nm and 6.11 nm in Ni-like Tb and amplification at 6.41 nm and 5.85 nm in Ni-like Dy. This scaling to shorter wavelengths was obtained by progressively increasing the pump pulse grazing incidence angle to access increased plasma densities. We experimentally demonstrate that the optimum grazing incidence angle increases linearly with atomic number from 17 deg for Z = 42 (Mo) to 43 deg for Z = 66 (Dy). The results will enable applications of sub-7 nm lasers at compact facilities
Micro-scale fusion in dense relativistic nanowire array plasmas
No full textAbstractNuclear fusion is regularly created in spherical plasma compressions driven by multi-kilojoule pulses from the world’s largest lasers. Here we demonstrate a dense fusion environment created by irradiating arrays of deuterated nanostructures with joule-level pulses from a compact ultrafast laser. The irradiation of ordered deuterated polyethylene nanowires arrays with femtosecond pulses of relativistic intensity creates ultra-high energy density plasmas in which deuterons (D) are accelerated up to MeV energies, efficiently driving D–D fusion reactions and ultrafast neutron bursts. We measure up to 2 × 106 fusion neutrons per joule, an increase of about 500 times with respect to flat solid targets, a record yield for joule-level lasers. Moreover, in accordance with simulation predictions, we observe a rapid increase in neutron yield with laser pulse energy. The results will impact nuclear science and high energy density research and can lead to bright ultrafast quasi-monoenergetic neutron point sources for imaging and materials studies.</jats:p
0.85 PW laser operation at 3.3 Hz and high-contrast ultrahigh-intensity λ = 400 nm second-harmonic beamline
No full textWe demonstrate the generation of 0.85 PW, 30 fs laser pulses at a repetition rate of 3.3 Hz with a record average power of 85 W from a Ti:sapphire laser. The system is pumped by high-energy Nd:glass slab amplifiers frequency doubled in LiB3O5 (LBO). Ultrahigh-contrast λ = 400 nm femtosecond pulses were generated in KH2PO4 (KDP) with>40% efficiency. An intensity of 6.5 × 1021 W∕cm2 was obtained by frequency doubling 80% of the available Ti:sapphire energy and focusing the doubled light with an f∕2 parabola. This laser will enable highly relativistic plasma experiments to be conducted at high repetition rate
Wavefront improvement in an injection-seeded soft x-ray laser based on a solid-target plasma amplifier
No full textInternational audienceThe wavefront of an injection-seeded soft x-ray laser beam generated by amplification of high-harmonic pulses in a lambda = 18.9 nm molybdenum plasma amplifier was measured by a Hartmann wavefront sensor with an accuracy of lambda/32 root mean square (rms). A significant improvement in wavefront aberrations of 0.51 +/- 0.03 lambda rms to 0.23 +/- 0.01 lambda rms was observed as a function of plasma column length. The variation of wavefront characteristic as a function time delay between the injection of the seed and peak of soft x-ray amplifier pump was studied. The measurements were used to reconstruct the soft x-ray source and confirm its high peak brightness. (C) 2013 Optical Society of Americ
Potential impact of methyl isobutyl ketone (MIBK) on phenols degradation in an UASB reactor and its degradation properties
No full textMethyl isobutyl ketone (MIBK) as a solvent is extensively used for the phenols extraction from the wastewater, so it is unavoidable to expose in the effluent due to the solubility and leakage problem. The present study evaluated the impact of MIBK on phenols degradation in an UASB reactor and analyzed its degradation properties. The results indicated that the continuous dosing (0.1 g L−1) and impact (10 g L−1) of MIBK had limited effect on phenols removal (1–2% reduction) in the UASB reactor, but the specific methanogenic activity (SMA) values of sludge decreased by 45–75% after MIBK exposure. Anaerobic degradation rate of MIBK fitted well to a pseudo-first-order kinetic equation with respect to the initial concentration of 35 mg L−1 (k = 0.0115 h−1, R2 = 0.9664). Furthermore, the relative methane generation rate constants of MIBK were 0.00816, 0.00613, 0.00273, and 0.00207 d−1 at the initial concentrations of 0.1, 0.5, 5, and 10 g L−1, respectively. MIBK showed higher inhibitory effect on the methanogenesis than on phenols degradation. This study pointed out that the industrial installations should consider the influence of solvent on anaerobic treatment of phenolic wastewater.Sanitary Engineerin
NEGATIVE ION PHOTOELECTRON SPECTROSCOPY OF SOLVENT-STABILIZED ANIONS
No full textAuthor Institution: Department of Chemistry, Johns Hopkins UniversitySolvent-stabilized anions of organic molecules, such as napthalene, pyrimidine, and pyridine, were invesitigated via negative ion photoelectron spectroscopy. In addition to determining the minimum number of solvent molecules needed to form a stable anion, we also determined that the excess charge was in each case located on the organic molecule and not on its solvent. By extrapolation, we determined the electron affinities of bare organic molecules
Recombinant Lysostaphin Protects Mice from Methicillin-Resistant Staphylococcus aureus Pneumonia
No full textThe advent of methicillin-resistant Staphylococcus aureus (MRSA) and the frequent and excessive abuse of ventilators have made MRSA pneumonia an inordinate threat to human health. Appropriate antibacterial therapies are crucial, including the use of lysostaphin as an alternative to antibiotics. To explore the potential use of lysostaphin as a therapeutic agent for MRSA pneumonia, mice were intranasally infected with MRSA and then treated with recombinant lysostaphin (rLys; 45mg/kg in the high-dose group and 1mg/kg in the low-dose group) (0.33mg/mL, 15mg/mL), vancomycin (120mg/kg) (40mg/mL), or phosphate-buffered saline (PBS, negative control) 4 h after infection. Therapeutic efficacy was assessed by mouse survival, lung histopathology, bacterial density in the lungs, bodyweight, lung weight, temperature, white blood cells counts, lymphocytes counts, granulocytes counts, and monocytes counts. The mice treated with rLys showed lower mortality, less lung parenchymal damage, and lower bacterial density at metastatic tissue sites than mice treated with PBS or vancomycin. The overall mortality was 100%, 60%, 40%, and 60% for the control, vancomycin, high-dose rLys, and low-dose rLys groups, respectively. These findings indicate that, as a therapeutic agent for MRSA pneumonia, lysostaphin exerts profound protective effects in mice against the morbidity and mortality associated with S. aureus pneumonia.Biotechnology & Applied MicrobiologyMedicine, Research & ExperimentalSCI(E)[email protected]; [email protected]
