18 research outputs found
Possibility of measurement of cross section and vector analyzing powers of p−^{3}He scattering at the Bronowice Cyclotron Center
A new possibility of continuation of few-nucleon dynamics studies at medium energies has appeared together with a new facility at the Institute of Nuclear Physics PAN in Kraków — The Bronowice Cyclotron Center (CCB). The new cyclotron PROTEUS provides a proton beam in an energy range of 70–230 MeV. Current progress in the theoretical calculations for four-nucleon (4N) systems is a main motivation to investigate p−^{3}He scattering. Due to the fact that the beam cannot be polarized, the only possibility to study spin observables is to build a polarized ^{3}He target system. A planned experiment assumes the construction of a cylindrical double Pyrex cell with separated pumping and target chambers with an additional polyamide film covering apertures for the passing beam and the reaction products. To polarize ^{3}He gas, the spin-exchange optical pumping method will be used
A novel system for patient ventilation and dosing of hyperpolarized ^{3}He for magnetic resonance imaging of human lungs
A versatile ventilator for controlling a patient’s breath cycle and dosing 3He gas has been designed and constructed. It is compatible with a medical magnetic resonance imaging scanner and can be incorporated into routine human lungs imaging procedure that employs hyperpolarized noble gas as a contrast agent. The system adapts to the patient’s lung volume and their breath cycle rhythm, providing maximum achievable comfort during the medical examination. Good quality magnetic resonance lung images of healthy volunteers were obtained. The system has the capability of recycling the exhaled gas to recover the expensive 3He isotope, and can be also adapted to human lung imaging with hyperpolarized 129Xe
Metastability exchange optical pumping of 3He gas up to hundreds of millibars at 4.7 Tesla
Knoevenagel condensation of cyclic ketones with benzoylacetonitrile and N,N′-dimethylbarbituric acid : application of sterically hindered condensation products in the synthesis of spiro and dispiropyrans by hetero-Diels–Alder reactions
Inverse-electron demand Diels–Alder cycloadditions of sterically hindered cycloalkylidene derivatives of benzoylacetonitrile and N,{N}′-dimethylbarbituric acid with enol ethers, cyclic enol ethers and also sterically hindered cycloalkylidenecycloalkanes were investigated. New spiro, dispirodihydropyrans, spirouracils, and dispirouracils were obtained. To confirm the experimental results, frontier orbital HOMO and LUMO energies of heterodienes and dienophiles were calculated by semi-empirical AM1, PM3 methods and ab initio Hartree–Fock calculations
Optical hyperpolarization of noble gases for medical imaging
Magnetic resonance imaging (MRI) of human or animal lungs became possible with the application of hyperpolarized noble gases, such as ^{3}He or ^{129}Xe. This method allows obtaining information on lung morphology and functionality. Introduction of hyperpolarized noble gases provided as well a new tool for non-medical applications such as neutron filters or nuclear magnetic resonance (NMR) spectroscopy studies in porous materials. The high polarization of noble gases is possible using so-called optical pumping methods. In this chapter the two most common polarization techniques of noble gases (^{3}He and ^{129}Xe), spin exchange optical pumping (SEOP) and metastability exchange optical pumping (MEOP) are presented. Variations of these methods delivering higher ^{3}He and ^{129}Xe polarization including hybrid SEOP or MEOP in standard conditions and in elevated pressure and high magnetic fields are also reported. A short description of the equipment used for gas polarization is also provided
Magneto-optical trap for rubidium atoms
A magneto-optical trap recently built in our laboratory is described. The principles of operation and construction details are given together with the description of the lasers used in the set-up
Nonlinear spectroscopy of cold, trapped atoms
We report on our studies of atoms contained in a magneto-optical trap using the nonlinear spectroscopy methods. Absorption and four-wave mixing signals are recorded for the probe frequency near the cooling transition frequency and the two methods are compared. The differences in the signal structure and their sensitivity on external conditions are discussed. It is revealed that central feature of these spectra consists of several contributions of different origin