61 research outputs found
I-BEAT: New ultrasonic method for single bunch measurement of ion energy distribution
The shape of a wave carries all information about the spatial and temporal
structure of its source, given that the medium and its properties are known.
Most modern imaging methods seek to utilize this nature of waves originating
from Huygens' principle. We discuss the retrieval of the complete kinetic
energy distribution from the acoustic trace that is recorded when a short ion
bunch deposits its energy in water. This novel method, which we refer to as
Ion-Bunch Energy Acoustic Tracing (I-BEAT), is a generalization of the
ionoacoustic approach. Featuring compactness, simple operation,
indestructibility and high dynamic ranges in energy and intensity, I-BEAT is a
promising approach to meet the needs of petawatt-class laser-based ion
accelerators. With its capability of completely monitoring a single, focused
proton bunch with prompt readout it, is expected to have particular impact for
experiments and applications using ultrashort ion bunches in high flux regimes.
We demonstrate its functionality using it with two laser-driven ion sources for
quantitative determination of the kinetic energy distribution of single,
focused proton bunches.Comment: Paper: 17 Pages, 3 figures Supplementary Material 16 pages, 7 figure
The proton radius puzzle
High-precision measurements of the proton radius from laser spectroscopy of
muonic hydrogen demonstrated up to six standard deviations smaller values than
obtained from electron-proton scattering and hydrogen spectroscopy. The status
of this discrepancy, which is known as the proton radius puzzle will be
discussed in this paper, complemented with the new insights obtained from
spectroscopy of muonic deuterium.Comment: Moriond 2017 conference, 8 pages, 4 figure
Improved X-ray detection and particle identification with avalanche photodiodes
Avalanche photodiodes are commonly used as detectors for low energy x-rays.
In this work we report on a fitting technique used to account for different
detector responses resulting from photo absorption in the various APD layers.
The use of this technique results in an improvement of the energy resolution at
8.2 keV by up to a factor of 2, and corrects the timing information by up to 25
ns to account for space dependent electron drift time. In addition, this
waveform analysis is used for particle identification, e.g. to distinguish
between x-rays and MeV electrons in our experiment.Comment: 6 pages, 6 figure
Séparations mécaniques fluide/solide
Licencedécantation gravitaire ; centrifugations (décantation centrifuge et cyclones) ; filtrations (sur support et en profondeur
A tale of two worlds:assessing the vulnerability of enclave shielding runtimes
status: publishe
A Lock-and-Kill anticancer photoactivated chemotherapy agent: this article is part of a Special Issue celebrating the 50thAnniversary of the American Society for Photobiology
Photosubstitutionally active ruthenium complexes show high potential as prodrugs for the photoactivated chemotherapy (PACT) treatment of tumors. One of the problems in PACT is that the localization of the ruthenium compound is hard to trace. Here, a ruthenium PACT prodrug, [Ru(3)(biq)(STF-31)](PF6 )2 (where 3 = 3-(([2,2':6',2″-ter- pyridin]-4'-yloxy)propyl-4-(pyren-1-yl)butanoate) and biq = 2,2'-biquinoline), has been prepared, in which a pyrene tracker is attached via an ester bond. The proximity between the fluorophore and the ruthenium center leads to fluorescence quenching. Upon intracellular hydrolysis of the ester linkage, however, the fluorescence of the pyrene moiety is recovered, thus demonstrating prodrug cellular uptake. Further light irradiation of this molecule liberates by photosubstitution STF-31, a known cytotoxic nicotinamide phosphoribosyltransferase (NAMPT) inhibitor, as well as singlet oxygen via excitation of the free pyrene chromophore. The dark and light cytotoxicity of the prodrug, embedded in liposomes, as well as the appearance of blue emission upon uptake, were evaluated in A375 human skin melanoma cells. The cytotoxicity of the liposome-embedded prodrug was indeed increased by light irradiation. This work realizes an in vitro proof-of-concept of the lock-and-kill principle, which may ultimately be used to design strategies aimed at knowing where and when light irradiation should be realized in vivo.Seventh Framework Programme (FP7)335879Metals in Catalysis, Biomimetics & Inorganic MaterialsSupramolecular & Biomaterials Chemistr
Colossal dielectric constants in transition-metal oxides
Many transition-metal oxides show very large ("colossal") magnitudes of the
dielectric constant and thus have immense potential for applications in modern
microelectronics and for the development of new capacitance-based
energy-storage devices. In the present work, we thoroughly discuss the
mechanisms that can lead to colossal values of the dielectric constant,
especially emphasising effects generated by external and internal interfaces,
including electronic phase separation. In addition, we provide a detailed
overview and discussion of the dielectric properties of CaCu3Ti4O12 and related
systems, which is today's most investigated material with colossal dielectric
constant. Also a variety of further transition-metal oxides with large
dielectric constants are treated in detail, among them the system La2-xSrxNiO4
where electronic phase separation may play a role in the generation of a
colossal dielectric constant.Comment: 31 pages, 18 figures, submitted to Eur. Phys. J. for publication in
the Special Topics volume "Cooperative Phenomena in Solids: Metal-Insulator
Transitions and Ordering of Microscopic Degrees of Freedom
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