Y.Y. Yang

Construction and tuning of BEPC mini-beta permanent quadrupole prototype

A large aperture and good field performance permanent quadrupole prototype for the Beijing Electron Positron Collider (BEPC) luminosity upgrade was made. This paper will describe the configuration, assembly, held measurement and tuning procedure used to get the required field quality

7Be, 8B+208Pb Elastic Scattering at Above-Barrier Energies

Angular distributions for the elastic scattering of 7Be and 8B by an enriched 208Pb target were measured at the Radioactive Ion Beam Line at Lanzhou (RIBLL). The incident energies of the radioactive beams were about three times the respective Coulomb barriers. A suppressed Coulomb-nuclear Interference Peak (CNIP) is not observed for 8B, a pronounced proton halo nucleus. Optical model fits were performed using Woods-Saxon potentials and the total reaction cross sections deduced. The results are discussed.

An experimental apparatus for EDXD of high pressure specimens using synchrotron radiation at BSRF

Abstract A high pressure energy dispersive X-ray diffraction apparatus on 3W1A beamline, at BSRF, is described. A ten-poles permanent magnetic wiggler provided white X-ray beam. The extreme high pressure up to 115xa0GPa has been obtained by a modified Mao-Bell diamond anvil cell. A motorized loading system with strain sensor can finely control the pressure change. The in situ experimental procedures are described. Some applications are also presented.

The readout design of Si-PIN detector in HXMT

The Medium Energy X-ray Telescope (ME), covering 5-30 keV, is one of the three main payloads of the Hard X-ray Modulation Telescope (HXMT). ME adopts an array of Si-PIN detectors. The detection area of one pixel is 56.25 mm2 , and the total detection area is 952 cm2 . The ME has a large active area while the pixel size is smaller. So the front-end electronics and forming electronics are realized by Application Specific Integrated Circuit (ASIC) chips. In this paper, we will describe the matching design of ME Si-PIN detector and ASIC, and the performance of the design. The energy response, temperature response, and dead time of a Two-Pixels Si-PIN detectors with the simplest readout electronics which is similar with ME, were tested on the Max Planck Institute for Extraterrestrial Physics PANTER X-ray test facility at Neuried by Munchen (Germany). The overall performance is quite similar to what was expected.

CDS4C: A novel CDS ASIC for a multi-readout X-ray CCD with a 0.032% INL

This work presents the development of a four-channel correlated double sampling (CDS) ASIC, named CD-S4C, targeting the readout of a type of multi-readout swept charge device (SCD) for applications in the fields of both X-ray spectroscopy and imaging. Compared with conventional CDS architecture based on clamping technique, the innovation of the CDS4C ASIC is that it not only moves the clamping switch out of the signal path but also omits the sampling switch, eliminating the nonlinearity and thermal noise introduced by the these switches. Besides, it is implemented in a fully differential topology which suppresses the second-order harmonic distortion, improving the linearity further more. A theoretical noise analysis taking into consideration of the limited bandwidth of the operational-amplifier (OPA) highly coincides with the simulation results. A prototype of the CDS4C ASIC is fabricated with Global Foundries 0.35μm CMOS process, the preliminary experimental results show that, within the effective input dynamic range of 0∼20mV which is equivalent to a wide range of soft X-ray energy band from 0 to 18.25keV, 0.032% integral nonlinearity (INL) and 35.5μV input-referred readout noise are achieved under 200kHz pixel rate with 8× gain, while the total power consumption is only 8.8mW from a single 3.3V supply voltage.

Two measurements of the 22Na+p resonant scattering via thick-target inverse-kinematics method

Na-22 is an important isotope for the study of extinct radioactivity, meanwhile its sufficiently long half life provides the possibility to observe live Na-22 in nearby nova explosions. The Na-22(p,gamma)Mg-23 is one of the key reactions that influence the Na-22 abundance in nova ejecta. To study the proton resonant states in Mg-23 relevant to the astrophysical Na-22(p,gamma)Mg-23 reaction rates, two measurements have been carried out at the CRIB separator of University of Tokyo, and the RIBLL secondary beamline in Lanzhou, respectively. The Na-22 secondary beam was produced via the H-1(Ne-22,Na-22) n charge exchange reaction. Thick-target inverse-kinematics method is applied to obtain the excitation function of Na-22+ p elastic scattering. Extended gas target and solid state polyethylene foil were used in the two measurements, respectively, to map the different excitation energy region of the compound nucleus Mg-23. Several new resonant levels are observed and their contribution to the Na-22(p,gamma)Mg-23 reaction rate is evaluated.