Xiangping Zhu

The estimation of charge footprint size of ultraviolet photon counting imaging detector with induction readout.

The structure and work principle of an ultraviolet photon counting imaging detector based on wedge and strip anode with induction readout mode are introduced. Two methods of estimating the charge footprint size are presented. One way is theoretical calculation and simulation. The physical course of electrons is simulated from the microchannel plate output side to the readout anode. The calculated results show that the final charge footprint size is sensitive to the thickness of ceramic and not sensitive to the charge footprint size on the Ge layer. The other way is experimental image estimation. The final charge footprint size can be estimated according to the position where the light line of resolution board image begins to bend. Both methods show that the charge footprint size is sensitive to the ceramic substrate. The two methods are simple and effective for estimation of charge footprint size of photon counting imaging detector with induction readout.

Correction of ultraviolet single photon counting image distortion

Single photon counting imaging technology has been widely used in space environment detection, astronomy observation, nuclear physics, and ultraweak bioluminescence. However, the distortion of the single photon counting image will badly affect the measurement results. Therefore, the correction of distortion for single photon counting image is very significant. Ultraviolet single photon imaging system with wedge and strip anode is introduced and the influence factor leading to image distortion is analyzed. To correct original distorted image, three different image correction methods, namely, the physical correction, the global correction, and the local correction, are applied. In addition, two parameters, i.e., the position index and the linearity index, are defined to evaluate the performance of the three methods. The results suggest that the correction methods can improve the quality of the initial image without losing gray information of each counting light spot. And the local correction can provide the best visual inspections and performance evaluation among the three methods.

Noninvasive blood glucose detection using a miniature wearable Raman spectroscopy system

In this Letter, a miniature wearable Raman spectroscopy system is developed. A wearable fiber-optic probe is employed to help the stable and convenient collection of Raman spectra. A nonlinear partial least squares model based on a multivariate dominant factor is employed to predict the glucose level. The mean coefficients of determination are 0.99, 0.893, and 0.844 for the glucose solution, laboratory rats, and human volunteers. The results demonstrate that a miniature wearable Raman spectroscopy system is feasible to achieve the noninvasive detection of human blood glucose and has important clinical application value in disease diagnosis.

Progress of laser cooling of 12C3+ ions at the CSRe

We have performed a test run for laser cooling experiments with 12C3+ ion beams at an energy of 122 MeV/u at the CSRe with a pulsed laser. During this beamtime a lot of progress have been made. This was the first time we could successfully separate the 12C3+ ions and 16O4+ ions in the Schottky spectrum with the help of electron cooling. And our newly installed CPM detector worked well during the experiment. We tried to see effects from the interaction of the pulsed laser light with the stored 12C3+ ion beams, but no cooling effects could yet be observed.

Progress of dielectronic recombination experiment at CSRm

The storage ring equipped with an electron cooler is an ideal platform for dielectronic recombination (DR) experiments. In order to fulfil the requirement of DR measurements at the main Cooler Storage Ring, a detuning system for the precision control of the relative energy between the ion beam and the electron beam has been installed on the electron cooler device. The test run using 7.0 MeV/u C6+ beam was performed to examine the influence of this system on the performance of the stored ion beam. The Schottky spectra and the ion beam currents were recorded to monitor the beam status. The influence of pulse heights and widths of the detuning voltage on the ion beam was investigated. For the small pulse height, the experimental results from the Schottky spectrum were in good agreement with the theoretical results. The frequency shift in the Schottky spectrum is significantly reduced for the short pulse width. For the large pulse height, an oscillation phenomenon was observed. From the Schottky spectrum, we found the oscillation amplitude is dependent on the pulse width of detuning and the ion beam intensity. The detailed description of the phenomenon and the theoretical model based on the plasma oscillation was discussed in this paper.

A new photon counting imaging detector for the Chinese ChangE-2 EUV explorer mission

This paper describes the preliminary design and performances of a new developed photon counting imaging detector for Chinese ChangE-2 EUV explorer mission. The detector consists of microchannel plate (MCP) stacks and wedge and strip anode and corresponding data read out electronics. The experimental results shows that the new developed detector has a spatial resolution of about 75μm, image distortions are small and dark noise count rate less than 0.4 counts cm-2s-1. The pulse height distribution vs MCP operating voltages and the flat field performances are also discussed.

Progress of laser cooling of relativistic Li-like C 3+ ion beams at the CSRe*

Laser cooling is one of the most promising techniques to reach high phase-space densities for relativistic heavy ion beams. Realizing a crystalline ion beam is one of the ultimate goals of laser cooling of heavy ion beams at storage rings [1]. Preparations for laser cooling of relativistic lithium-like C are being made at the experimental cooler storage ring (CSRe) in Lanzhou, China [2]. In September 2014 a test experiment was performed with C ion beams at an energy of 122 MeV/u on the CSRe with a pulsed laser system. A schematic view of the experimental setup is shown in figure 1. In the experiment C ions were produced by an Electron Cyclotron Resonance ion source (ECR). In the ECR, a significant fraction of O was produced alongside. Then the ions were accelerated by a Sector Focused Cyclotron (SFC), and injected into the main Cooler Storage Ring (CSRm). After accumulation and acceleration in the CSRm, the ion beams were extracted and injected into the CSRe at the energy of 122 MeV/u (at a velocity of 47% of the speed of light). Since the circumference of the CSRe is 128.8 m, this beam energy lead to the revolution frequency of 1.087 MHz. A pulsed UV laser system from HZDR was employed for this test laser cooling experiment. The closed 2s1/2―2p1/2 optical transition at a wavelength of 0 155.07   nm of the Li-like carbon ions was Doppler-