Octahedral metal cluster complexes have high potential for biomedical applications. In order to evaluate the benefits of these moieties for combined CT/X-ray luminescence computed tomography, this paper compares photoluminescence, radiodensity and X-ray induced luminescence properties of eight related octahedral molybdenum and tungsten cluster complexes [{M₆I₈}L₆]ⁿ (where M is Mo or W and L is I⁻, NO₃ ⁻, OTs⁻ or OH⁻/H₂O). This article demonstrates that despite the fact that molybdenum cluster complexes are better photoluminescence emitters, tungsten cluster complexes, in particular (Bu₄N)₂[{W₆I₈}I₆], demonstrate significantly higher X-ray induced luminescence due to a combination of relatively good photoluminescence properties and high X-ray attenuation. Additionally, photo-degradation of [{M₆I₈}(NO₃)₆]²⁻ was evaluated.

The development of water-soluble hexanuclear cluster complexes of low toxicity is a promising task due to their potential biomedical applications such as bioimaging and photodynamic therapy. Herein, we present the syntheses of two new water-soluble hexarhenium cluster complexes with terminal amphiphilic phosphine ligands, and delineate their photoluminescence and X-ray excited optical luminescence (XEOL) properties. These cluster complexes, namely [{Re₆Q₈}(PPh₂CH₂CH₂COO)₆]⁴⁻ (Q = S (1); Se, (2)), have the least cytotoxicity among all the tested hexanuclear metal-clusters, are capable of penetrating into cells and exhibit moderate photodynamic toxicity toward Hep-2 cells.

The Novosibirsk Free Electron Laser (NovoFEL) facility is able to produce high-power tunable terahertz (THz) laser radiation in quasi-continuous mode. The ability to control/shape this THz radiation is required in a number of user experiments. In this work we propose a modulation approach suitable for free electron lasers based on recuperation design. It allows for generating THz macropulses of a desirable length, down to several microseconds (limited by a quality factor of FEL optical resonator). Using this approach, macropulses in the time window from several microseconds to several hundred microseconds have been shown for three possible frequency ranges: mid-infrared (~1100 cm⁻¹), far-infrared (~200 cm⁻¹) and THz (~40 cm⁻¹). In each case, the observed rise and decay of the macropulse have been measured and interpreted. The advantage of using short macropulses at the maximum peak power available has been demonstrated with the time-resolved Electron Paramagnetic Resonance (EPR) spectroscopy.

Unlike synchrotrons with multiple beamlines, free electron lasers (FELs) are single-beam facilities, which nevertheless have a number of endstations. The latter requires development of complex radiation transport line, which should be efficient enough to avoid scaling down the FEL capabilities. Keeping the beam shape and radiation power level along the beamline is a challenge because the total length of the FEL radiation transport line can exceed a hundred meters. The FELs around the world differs each other in both radiation parameters and endstations layout requiring individual design of their radiation transport lines. In this work we describe the 120-m beamline for transporting the radiation of the Novosibirsk free electron laser facility (NovoFEL), consisting of three FELs of the terahertz (THz), far-infrared, and mid-infrared ranges. The radiation of these three FELs is directed to the same beam transport channel, which is able to deliver the radiation to any of 14 endstations already commissioned. To compare the expected beam parameters with the actual ones, the radiation intensity distribution was measured in a number of places of the beamline that are THz radiation outputs for some endstations. Possible causes of the parameters mismatching observed for distant endstations are discussed. The problem of radiation absorption by water vapor is considered in detail.

X-irradiation of alkane solutions of N,N-dimethylaniline with various organic luminophores produces characteristic emission bands ascribed to the corresponding exciplexes. In contrast to optical generation, which requires diffusion-controlled quenching of excited states, an additional channel of exciplex formation via irreversible recombination of radical ion pairs is operative here, which produces exciplexes in solution with high efficiency even for p-terphenyl and diphenylacetylene having fluorescence decay times of 0.95 ns and 8 ps, respectively. The exciplex emission band is sensitive to an external magnetic field and exerts a very large observed magnetic field effect of up to 20%, the maximum possible value under the conditions of the described experiment.