A Bi-Dimensional Multi-Wire Cathode Strip Detector for Fission Fragments
A large area bi-dimensional position sensitive multi-wire cathode strip detector (MCSD) has been developed for the detection of fission fragments (FFs). The performance of the detector has been characterized with FFs from 252Cf and α particles from 241Am-239Pu sources. The position information is obtained from the measurement of time delay signals of the cathode strips (X-direction) and split-cathode wires (Y-direction) with respect to the timing signal from the anode wires. The position resolution is found to be about 1.0 and 1.5 mm in X-and Y-directions respectively.
Reduction in non-linearity in position-sensitive MWPCs
Measurements of differential nonlinearity have been made with a small multiwire proportional chamber (MWPC) for two special cathode strip geometries. The results have been compared with those for conventional strip geometry and with theoretical predictions. With the ratio of sampling node separation to anode-cathode check separation at the exceptionally large value of 2.4, a peak-to-peak differential nonlinearity of 72% was observed for the conventional geometry. The first special geometry used two intermediate strips between the readout strips, with near optimum capacitive coupling between them, to achieve a differential nonlinearity of about 4% at the same ratio of 2.4. In the second special geometry, cathode strips with optimum-depth zigzag-shaped boundaries yielded an experimental differential nonlinearity of about 7%. >
Quantitative and qualitative relationship between swirl burner operatingconditions and pulverized coal flame length
Abstract Currently, there are used in power plants two types of burners to combustion the pulverized coal: jet burners and swirl burners. Most of the published works in the field of analysis of burners operating conditions are related to jet burners and are limited to initial region of the flame at the outlet of the burner. For jet burners an offset between the burner outlet and the flame beginning point could be analyzed. In the case of swirl burners with the pre-mixing diffuser chamber an offset between flame ignition point and burner outlet is usually not visible. Because already in the pre-mixing diffuser chamber of swirl burner occurs the ignition of coal-dust together with oxidant-gas cloud and thereby the formation of the flame. Therefore, the analysis of operating conditions for this types of burners requires a different approach. There is a lack of researches, in which will be analyzed changes of the flame length, that are caused by changes of design and operating parameters of swirl burner with the pre-mixing diffuser chamber. Therefore the aim of this study was to implement and verify the methodology for estimating the flame length, which will allow monitoring changes of operating conditions, that are caused by changes of design and operating parameters of swirl burner with the pre-mixing diffuser chamber. To carry out the analysis of the image of the coal flame, the two algorithms have been presented. This two algorithms, being based on the video images of the coal flame allows to specify and detect the end point of the flame and on that basis the length of the flame, as well as the fluctuation changes of flame length can be later determined. Both, the change thermal loads of coal burner, streams of secondary air, as well as the constructional change of the angle of swirler assemblies, resulted in distinct changes in the length of the pulverized coal flame.