The Research On The Full-length Prototype Of Beijing Spectrometer Ⅲ Drift Chamber

The Beijing Electron Position Collider (BEPC) and the Beijing Spectrometer (BES) are upgrading now. The drift chamber is a very important detector in BES. The full-length prototype is designed to simulate the small cell sructure of the BESIII drift chamber (DC) veritably, study the whole function and optimize working parameters for MDC with stereo wire and full length.At first,it describes structure of the full-length prototype, manufacturing craft and prepare to work,including sting,sealing,wire tension and leak current measurement,mounting of the Preamp,gas system, high voltage system, reduction of noise and so on.The construction of full-length prototype provided valuable experience and important reference to the BESIII drift chamber.Then good function of the full-length prototype was performed using 55Fe 5.9Kev X_ray source. we can see that the uniformity of gas gain of the full-length prototype is well and it is effective for the compensation voltage to adjust the uniformity of gas gain of the boundary cells.Cosmic ray test was carried out to choose and optimize working parameters of full-length prototype and its data acquisition system, verify the electronics system about dynamic range ,drift time measurement search window , charge measurement integral width, work stability and electronics grounding and noise..In experiment,acquired abundant experience with the solution of actual problem and verified their reliability of physical design.This lays the foundations for the successful construction of the BESIII drift chamber and electrical system.In order to take further research of performace and optimize working parameters in strong magnetic field, Beam test was carried out.The test results showed that the full-length prototype and its data acquisition system could work successfully in the strong magnetic field with good performance.