A High-speed Nuclear Signal Acquision Card Based On ARM7

Nuclear signal data acquisition is an important part of the spectrometer. It carries on digitized processing on the nuclear detection pulse signal, and obtains the curve of signal amplitude distribution for spectrum analysis software. The traditional nuclear signal acquisition is big on heavy, volume and the power, so it is not advantage to the field analysis. The dissertation discusses about nuclear signal acquisition based on low power loss microprocessor (ARM7) and the high speed ADC chip (AD1605), designs the hardware circuit and software. The nuclear signal data acquisition card includes Multi-Channel pulse height Analyzer, digitized pulse amplification regulation circuit and voltage-stabilized source, and so on.The hardware adopts the LPC2148 chip based on ARM7 TDMI-S as controlling core, carrys on the JTAG simulation debugging, applys high speed and low power ADC (Analog-to-Digital Converters). The card makes use of 40KB SRAM which is contained by LPC2148 chip as exterior data-carrier storage. With the 512KB of Flash debugging space, it may realize In-System Programming and In-application programming. The internal SPI with the digital potentionmeter make the digitized adjustment of to the amplifier, the adjustment precision achieves 1/10000. The internal timer with the exterior hardware circuit may complete the deduction of the dead time and measurement of live time. It adopts the DC/DC transfer circuit, which can transform the 5～12 V into 3.3V, 5.0V and±9V for the system, enlargeing the application domain. Acquisition card connects with computer on line by using RS-232 interface. Software system is written by C Language and is advantageous for second development. This card can be used in portable integrated and the intellectualized X-Ray fluorescence analyzer, gamma spectrometer and so on. It can also be applied in the room nuclear instrument and other experimental equipments, and promotes the nuclear instrument development.