The 4 X 4 multiple CCD X-ray detector installed in the beamline 45XU of the SPring-8 facility in Japan was examined by acquiring X-ray diffraction images of lysozyme crystals. The detector system was calibrated at the beamline by observing X-ray images of a flood-field and a mask pattern generated by the synchrotron radiation X-ray beam. It was found in the present work that the quality of the X-ray images observed is limited by an unexpected spike noise, the origin of which was suspected to be the (gamma) -rays emitted from the radioisotopes remaining in the X-ray scintillating screen. Image analysis carried out with a median filter predicted, however, that the image quality could be as high as designed, once the noise as well as the grain colonization is removed from the screen.
A position-sensitive ionization chamber has been developed with backgammon-type-segmented electrodes. This novel detector possesses a linear range of 8 mm for determining the incident position of the X-ray beam incoming. The position resolution was found to be better than 10 micrometers , probably close the sub-micrometer region. Owing to its high spatial resolution, the position-sensitive ionization chamber was able to commit that the gradual decrease observed in the X-ray beam intensity at the BL44B2 of the SPring-8 facility was mainly due to the spatial variation of the X-ray beam position in time. The present work also confirmed the applicability of the novel detector to the feedback correction system for the beam stabilization.
Double-differential cross sections (DDXs) of emitted protons and αs particles were measured for proton-induced reactions on 12C at 14, 18 and 26MeV in order to investigate the 12C(p, p′3α) breakup reaction. The experimental DDXs were analyzed on the assumption that the (p, p′3α) reaction proceeds through two major processes, a three-body simultaneous breakup (3BSB) process (i.e., p+12C→p+α+8Be*2094Mev) and sequential decay processes from unstable nuclei produced by (p, p′) and (p, α) reactions (i.e., 12C, 9B, 8Be and 5Li). Partial cross sections for the various reaction channels were extracted from the measured DDXs by a least squares method with two fitting functions: a three-body phase distribution function for the 3BSB process and a Breit-Wigner function for the transition to a discrete level in the first step of the sequential decay process. The result showed that the 12C(p, p′3α) reaction took place predominantly via nearly isotropic particle emission in the 3BSB process, and emission of protons and α particles with low energies was explained well by the sequential decay via 12C* and 9Bg.s Experimental (p, p) and (p, p′) scattering cross sections at 26 MeV were reproduced well by the coupled-channels calculation with the soft-rotator model. The experimental DDXs were compared with a Monte Carlo calculation based on the SCINFUL/DDX code and the latest intermediate energy nuclear data evaluation library LA150.
A position-sensitive ionization chamber has been developed with backgammon-type-segmented electrodes. This novel detector possesses a linear range of 8 mm for determining the incident position of the X-ray beam incoming. The position resolution was found to be less than 10 microm, probably close the sub-micrometer region. Owing to its high spatial resolution, the position-sensitive ionization chamber was able to commit that the gradual decrease observed in the X-ray beam intensity at a SPring-8 beamline was mainly due to the spatial variation of the X-ray beam in time. The present work also confirmed the applicability of the novel detector to the accurate monochromator adjustment for experiments using diamond anvil cells.
The Station Equipment Group of JASRI and the SR Structural Biology Research Group of RIKEN have designed and constructed a 4 × 4 array of CCD X-ray detectors called the `multiple charge-coupled-device X-ray detector (MCCDX)' in collaboration with EEV in the UK. The novel features of the system are the lower demagnification factor of its fibre-optics taper assembly and the higher operational temperature, when compared with similar detector systems already in existence. The present paper describes the design concepts of the MCCDX system as well as the basic characterization of the constructed MCCDX system, which was carried out by using a conventional X-ray generator system prior to its installation on RIKEN beamline I (BL45XU) of the SPring-8 facility.
Double-differential cross sections (DDXs) of emitted protons and αs particles were measured for proton-induced reactions on 12C at 14, 18 and 26MeV in order to investigate the 12C(p, p′3α) breakup reaction. The experimental DDXs were analyzed on the assumption that the (p, p′3α) reaction proceeds through two major processes, a three-body simultaneous breakup (3BSB) process (i.e., p+12C→p+α+8Be*2094Mev) and sequential decay processes from unstable nuclei produced by (p, p′) and (p, α) reactions (i.e., 12C, 9B, 8Be and 5Li). Partial cross sections for the various reaction channels were extracted from the measured DDXs by a least squares method with two fitting functions: a three-body phase distribution function for the 3BSB process and a Breit-Wigner function for the transition to a discrete level in the first step of the sequential decay process. The result showed that the 12C(p, p′3α) reaction took place predominantly via nearly isotropic particle emission in the 3BSB process, and emission of protons and α particles with low energies was explained well by the sequential decay via 12C* and 9Bg.s Experimental (p, p) and (p, p′) scattering cross sections at 26 MeV were reproduced well by the coupled-channels calculation with the soft-rotator model. The experimental DDXs were compared with a Monte Carlo calculation based on the SCINFUL/DDX code and the latest intermediate energy nuclear data evaluation library LA150.
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