Proton elastic scattering and proton induced γ-ray emission cross-sections on Na from 2 to 5 MeV

Differential cross-sections for proton elastic scattering on sodium and for γ-ray emission from the reactions ²³Na(p,p′γ)²³Na (E_γ = 440 keV and E_γ = 1636 keV) and ²³Na(p,α′γ)²⁰Ne (E_γ = 1634 keV) were measured for proton energies from 2.2 to 5.2 MeV using a 63 μg/cm² NaBr target evaporated on a self-supporting thin C film.The γ-rays were detected by a 38% relative efficiency Ge detector placed at an angle of 135° with respect to the beam direction, while the backscattered protons were collected by a Si surface barrier detector placed at a scattering angle of 150°. Absolute differential cross-sections were obtained with an overall uncertainty estimated to be better than ±6.0% for elastic scattering and ±12% for γ-ray emission, at all the beam energies.To provide a convincing test of the overall validity of the measured elastic scattering cross-section, thick target benchmark experiments at several proton energies are presented.     

Design of USB2.0 wireless network Based on nRf2401 and CP2102

This is a design of High- speed wireless network PC- USB2.0- MCU card with nRf2401 and CP2102. The design use CP2102 for USB2.0 interface and nRf2401 for wireless data transmission. We can get the free driver program for CP2102 from manu- factory, and with it we can have comfortable design product. This article expatiates the principle and hardware and software design.     

USB、RS232/RS422接口转换电路的设计

由于USB接口正逐步替代传统的RS232接口成为PC机的标准接口,USB接口转换电路的设计就很有必要。采用Silicon公司高集成度的USB-UART桥接器件CP2102,辅以简单的外部电路,实现了RS232/RS422接口与USB接口转换电路的设计。其中在详细介绍CP2102结构和特性的基础上,给出了接口转换的硬件电路图,最后简单介绍了转换器的工作原理。