The Development In Electronics System For Electron Spin Detector

Spin electronic is one of the basic attributes of electrons. Spintronics is a rising and attended research field, which is based on different orientation of electron spin, studying the transport properties of electron in a certain spin state electron.It is also one of the hot topics in condensed matter physics presently.It can be directly measured the polarization and the polarization direction of electron spin by using photomultiplier scintillator and photomultiplier to measuring high energy Mott scattered electron. Based on this, the essay designs electronics system for the electron spin detector with the electron spin detection technology.The article first analyzes the specific requirements of the electron spin detector for the electronic system, considering factors such as working environment and noise, designing high voltage signal processing unit, which works in30KV high voltage environment, and low voltage control unit with displaying. These two units use photoelectric conversion for isolation and communication.The signal processing unit consists of a high-speed, high-gain and low-noise preamplifier, a high-speed pulse amplitude comparator, a anti-coincidence circuit and a high-speed counter of which rate is up to20MHz.The whole unit applies a rechargeable lithium battery to charging,In this unit, the preamplifier signal changes a current pulse signal l00uA with20-30ns width into a voltage pulse signal1Vpp with30ns width; the high-speed pulse amplitude comparator has an adjustable threshold of100mV-4.0V, a response time of2.5ns. Low voltage control unit mainly provides key-press input, displaying the experimental conditions, and communicating with PC through USB interface. Moreover, a standard2U chassis, assembling this unit, meets the equipment and facility specifications.The electronics system design of the electron spin detectors have been applied to reflective spin-resolved electron spectroscopy experiment. The whole system runs stably with friendly user interface, which fully meets the design requirements.