Universal approach to in situ light-coupled NMR spectroscopy without fibre optics

In situ illumination of liquid-state nuclear magnetic resonance (NMR) samples makes it possible for a wide range of light-dependent chemical and biological phenomena to be studied by the powerful analytical technique. However, the position of an NMR sample deep within the bore of the spectrometer magnet renders such illumination challenging. Here, we demonstrate a photo-NMR insert device (NMRtorch) where a lighthead containing an LED array is attached directly to the top of an NMRtorch tube. The wall of the tube itself acts as a light guide, illuminating the sample from the outside. We explore how this new setup performs in a number of photo-NMR applications, including photoisomerisation and photo-chemically induced dynamic nuclear polarisation (photo-CIDNP), and demonstrate the potential for ultraviolet (UV) degradation studies with continuous online NMR assessment. This setup enables users of any typical liquid-state spectrometer to easily perform in situ photo-NMR experiments, using a wide range of wavelengths.

Calculation of field of spectrometric magnet with 0.13 m gap

The spectrometric magnet is widely used in experiments on highenergy physics and a number of other fields. In this report, we present the results of calculating the magnetic field for a variant of a magnet with an interpolar gap of 0.13 m. Our spectrometer magnet has external dimensions of 2.95 x 2.12 x 1.62 m and an aperture (occupied by the beam) of 0.30 x 0.13 m. The simulation was carried out using an integral method of magnetostatics. The results of the calculated field distribution of the analyzing magnet with interpolar 0.13 m gap are given. The calculation was performed for the volume 0.33 x 0.0645 x 1.5 m, the volume of overlapping dimensions. The calculation of the spatial distribution of the three components of the magnetic field of the magnet described in the work is performed to obtain the information about the magnitude and uniformity of the magnetic field for different modes of operation of the spectrometer. The obtained results are planned for using in the processing of physical data.

NEUTRAL KAON PHOTOPRODUCTION AT LNS, TOHOKU UNIVERSITY

The elementary photo-strangeness production process has been intensively studied based on the high-quality data of the charged kaon channel, γ + p → K+ + Λ(Σ0). However, there had been no reliable data for the neutral kaon channel γ + n → K0 + Λ(Σ0) and the theoretical investigations suffer seriously from the lack of the data. In order to have reliable data for the neutral kaon photo-production data, substantial effort has been made to measure the γ + n → K0 + Λ process in the π+π- decay channel, using a liquid deuterium target and a tagged photon beam (Eγ = 0.8-1.1 GeV ) in the threshold region at the Laboratory of Nuclear Science (LNS), Tohoku University. We have taken exploratory data quite successfully with the use of Neutral Kaon Spectrometer (NKS) at LNS-Tohoku in 2003 and 2004. The data is compared to theoretical models and it indicates a hint that the K0 differential cross section has a backward peak in the energy region. The second generation of the experiment, NKS2, is designed to extend the NKS experiment by considerably upgrading the original neutral kaon spectrometer, fully replacing the spectrometer magnet, tracking detectors and all the trigger counters. The new spectrometer NKS2 has significantly larger acceptance for neutral kaons compared with NKS, particularly covering forward angles and much better invariant mass resolution. The estimated acceptance of NKS2 is three (ten) times larger for [Formula: see text] than that of NKS. The spectrometer is newly constructed and installed at the Laboratory of Nuclear Science, Tohoku University in 2005. The deuterium target data was taken with tagged photon beam in 2006-2007. We will report recent results of NKS2 in this paper. Additionally, a status of the upgrade project that gives us larger acceptance and capability of K0 + Λ coincidence measurement will be presented.