Measurement Of Cross Section Of ¹²C+¹³C Fusion Reaction And Study Of Position Sensitive Detector Based On Microchannel Plate

The ¹²C+¹²C fusion reaction is one of the most important reactions in the nuclear astrophysics.The temperature of carbon burning varies from 0.8-1.2GK,corresponding to 1-3MeV,.All the measurements,during the last decades,have been limited to the energy above 2.1MeV.The cross section in lower energy has to be obtained based on the theoretical extrapolation.However,due to the strong narrow resonances in ¹²C+¹²C reaction,theoretical predictions become very difficult and are no consistent with each other.In contrast to the complicated resonances in ¹²C+¹²C system,the ¹²C+¹³C behaves more smoothly.Therefore,the measurement of ¹²C+¹³C can be used to constrain the cross section of ¹²C+¹²C and evaluate the extrapolation theories.The experiment is performed to measure the cross section of ¹²C+¹³C fusion reaction in the 3MV Tandem accelerator of Sichuan University with the mass center energy varying from 4.13 to 5.76MeV.In this experiment,both thick target and thin target were used to measure the online characteristic?-rays emitted from four main decay channels,corresponding to the n,p,?and pn emissions,respectively.The decay of residual nucleus ²⁴Na for some targets were also measured offline.TALYS was used to calculate the branching ratios for each exit channel of ¹²C+¹³C and populations of individual states in the residuals.The total fusion cross sections were deduced by correcting the gamma-ray yields and compared with the previous measurements.Our result agrees with the data of Dasmahapatra et al.,but 10%higher than that of Dayras et al..Finally,the systematic uncertainties from the branching ratio corrections in both online and offline measurements were reviewed and 13.76%uncertainty was decided when the cross section of ²⁴Na channel was transformed to the total fusion cross section.Additionally,the study of position-sensitive detector based on microchannel plate?MCP?was also discussed in this thesis,which is designed for the measurements of astrophysically important??,p?reactions.In this work,the right-angle deflected field cage and tilted cage at 45 degree with respect to the incident direction were both studied.In order to improve the position resolution,different versions of the anode readout pad were tested and discussed here.Finally,the test results showed that our MCP detector could reach the level required by the future experiments.