Polarized atomic beam sources have been in operation for many years to produce either nuclear polarized atomic hydrogen or deuterium beams. In recent experiments, such a source was used to polarize ...both isotopes independently at the same time. By recombination of the atoms, hydrogen-deuterium molecules with all possible nuclear spin combinations can be created. Those spin isomers are useful for further applications, like precision spectroscopy, as polarized targets for laser-particle acceleration, polarized fuel for fusion reactors, or as an option for future measurements of electric dipole moments.
The nuclear
dd
-fusion reaction can proceed by three possible channels:
,
,
. Interest in
dd
-fusion has been aroused by both fundamental research and astrophysics and applied science, particularly ...in the field of fusion reactor development. In the 1970s, the idea of studying the nuclear
dd
-fusion reaction using polarized deuteron beams was proposed at the Kurchatov Institute. The development of this idea was continued in the PolFusion (polarized fusion) nuclear physics experiment, which aims at studying the reaction of nuclear
dd
synthesis with polarized source particles in the low energy region. The experiment is planned to measured the scattering asymmetries of
dd
-fusion reaction products in the final state at different mutual orientation of the spins of colliding deuterons in the energy range 10–100 keV. The authors present an overview of the status of the experiment.
The study of DD reactions, especially with polarized reactants, helps for better understanding of the processes taking place in nuclear astrophysics and fusion reactors. At PNPI Gatchina, Russia, the ...PolFusion experiment with crossing of two polarized beams, i.e. a deuteron and a deuterium beam, is able to measure angular distributions of the differential cross section and, therefore, the spin-correlations coefficients with different combinations of the adjustable nuclear polarization of both beams with a center-of-mass energy between 10 to 100 keV. Some improvements and fine-tuning of the polarized ion source are performed and presented. The atomic beam source for the jet target has been modified as well. An unpolarized experiment with a 10 keV ion beam and heavy water vapor as a target has been carried out with successful registration of the fusion products.
The PolFusion experiment is under preparation at the National Research Center Kurchatov Institute—PNPI, in collaboration with Forschungszentrum Juelich, Germany, and INFN/University of Ferrara, ...Italy; the experiment will study the
2
H(
d
,
n
)
3
He and
reactions with a polarized beam and target at low energies up to 100 keV. In this experiment, the differential cross sections and spin-correlation coefficients will be measured for various beam and target polarizations. The status of the PolFusion experiment is discussed. The paper contains a brief review of the theoretical models that can be used to describe
dd
fusion. The mathematical calculations based on partial wave decomposition that can be used for processing the obtained experimental data are considered.
The CBM RICH project Adamczewski-Musch, J.; Becker, K.-H.; Belogurov, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Letnik:
766
Journal Article
Recenzirano
The Compressed Baryonic Matter (CBM) experiment will study the properties of super dense nuclear matter by means of heavy ion collisions at the future FAIR facility. An integral detector component is ...a large Ring Imaging Cherenkov detector with CO sub(2) gas radiator, which will mainly serve for electron identification and pion suppression necessary to access rare dileptonic probes like e super(+)e super(-) decays of light vector mesons or J/ psi psi . We describe the design of this future RICH detector and focus on results obtained by building a CBM RICH detector prototype tested at CERN-PS.
The Compressed Baryonic Matter (CBM) experiment at the Facility for Antiproton and Ion Research (FAIR) at Darmstadt will be a dedicated heavy-ion experiment for the investigation of baryonic matter ...at highest net-baryon densities. A RICH detector with CO
2 as radiator gas is being developed for clean and efficient electron identification which will be necessary for the measurement of some of the key observables of the physics program of CBM. The status of the development of this RICH detector and results on R&D activities concerning self-triggered readout electronics for PMTs, studies on the usage of wavelength-shifting films, as well as the evaluation of glass mirrors from industrial providers will be presented.
Event reconstruction in the RICH detector of the CBM experiment at FAIR Adamczewski, J.; Becker, K.-H.; Belogurov, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Letnik:
766
Journal Article
Recenzirano
The Compressed Baryonic Matter (CBM) experiment at the future FAIR facility will investigate the QCD phase diagram at high net-baryon densities and moderate temperatures. One of the key signatures ...will be di-leptons emitted from the hot and dense phase in heavy-ion collisions. Measuring di-electrons, a high purity of identified electrons is required in order to suppress the background. Electron identification in CBM will be performed by a Ring Imaging Cherenkov (RICH) detector and Transition Radiation Detectors (TRD). In order to access the foreseen rare probes, the detector and the data acquisition have to handle interaction rates up to 10 MHz. Therefore, the development of fast and efficient event reconstruction algorithms is an important and challenging task in CBM. In this contribution event reconstruction and electron identification algorithms in the RICH detector are presented. So far they have been developed on simulated data but could already be tested on real data from a RICH prototype testbeam experiment at the CERN-PS. Efficient and fast ring recognition algorithms in the CBM-RICH are based on the Hough Transform method. Due to optical distortions of the rings, an ellipse fitting algorithm was elaborated to improve the ring radius resolution. An efficient algorithm based on the Artificial Neural Network was implemented for electron identification in RICH. All algorithms were significantly optimized to achieve maximum speed and minimum memory consumption.
Neuroimmune interactions pathways are the current interests of neuroimmunophysiology. As it shown, n. vagus is a part of neuroimmune communications, so determination of activation patterns of n. ...vagus is the relevant task. The aim of the study is to determine the amount of с-Fos-positive neurons in nuclei tractus solitarius (NTS) and dorsal motor nuclei (DMX) in rat medulla oblongata after subdiaphragmatic vagotomy and various antigens administration. Immunohistochemistry and morphometry were performed for determination of с-Fos-positive neurons amount in different zones of NTS and DMN. In the cells of DMX were not abserved any с-Fos-positive neurons in control and after subdiaphragmatic vagotomy. LPS administration (500 µg/kg) induced the increasing of с-Fos-positive neurons amount in NTS, particularly in medial NTS. Subdiaphragmatic vagotomy leads to increasing of с-Fos-positive neurons amount in NTS after LPS or SEB (500 µg/kg) administration. LPS injection after subdiaphragmatic vagotomy induced an activation of neurons of the lateral, medial and central NTS, while SEB administration induced only medial NTS activation. Therefore, the pattern of NTS response to the introduction of certain antigens are shown. Subdiaphragmatic vagotomy leads to activation of NTS after the introduction of LPS and SEB.
The CBM experiment at the future FAIR facility will explore nuclear matter at high net-baryon densities. One of the key observables is di-leptons as they penetrate the created matter without further ...strong interactions. A gaseous RICH detector in a standard projective geometry using spherical mirrors is one of two detector elements for the required electron identification. The mirror system consists of about 72 trapezoidal mirror tiles. Any misalignment between the tiles relative to the nominal common spherical surface leads to reduction of the reconstruction efficiency of Cherenkov rings and deterioration of their resolution. To determine tolerances in mirror misalignment extensive simulation and measurement studies were carried out. Pure CO sub(2) will be used as radiator gas. Gas contamination, mainly moisture and Oxygen, reduces the number of detected photons per ring and worsens the quality of reconstructed Cherenkov rings. Therefore a study was carried out to determine tolerances in radiator gas contamination.
Electron identification in the Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) will be performed using a gaseous RICH detector. Due to the UV ...transparency of the CO sub(2) radiator, a high photon detection efficiency of the PMTs in use at small wavelengths is favourable. The use of wavelength shifting (WLS) films aims at increasing the integral quantum efficiency of the photon sensors. WLS films absorb UV photons and re-emit photons at longer wavelengths where the quantum efficiency of common photocathodes is higher. As photon sensors, multianode PMTs (MAPMTs) with bialkali or superbialkali photocathodes and UV-extended windows are envisaged. We present quantum efficiency measurements with and without WLS coating for different types of MAPMTs as well as results from a beam test at the CERN PS. An increased photon yield was observed when using WLS films. In addition, we discuss the effect of WLS films on the spatial resolution of MAPMTs.
PDF
