Research on temperature measurement technology for graphite-cone-absorption-cavity absolute calorimeter.
The nonlinear effect of materials and sensors in high-energy laser calorimeters is especially obvious-due to the steep temperature gradients of their absorbers. Significant measurement errors occur when traditional integral temperature sensors and methods are utilized. In an effort to remedy this, a method is proposed in this paper in which an absorption cavity is divided into many parts and multiple discrete thermocouple sensors are used to measure the temperature rise of the absorbers. The temperature distribution in the absorbers is theoretically analyzed, numerically simulated, and verified through experimentation. Energy measurement results are compared according to the temperature distribution for different layouts of thermocouples. A high-accuracy calorimeter is developed by setting and optimizing thermocouple layout, as well as correcting various elements such as the specific heat of graphite and responsivity of thermocouples. The calorimeter employing this measurement method is calibrated against a standard energy meter, resulting in correction coefficient of 1.027 and relative standard deviation of the correction coefficient of only 0.8%. Theoretical analysis, numerical simulation, and experimental verification all prove that the proposed method successfully improves measurement accuracy.
State Key Laboratory of Precision Measurement Technology and Instrument, Tsinghua University, Beijing 100084, People's Republic of China.
Ji Feng
JF
Wei
Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900, People's Republic of China.
Fei
F
Lu
State Key Laboratory of Precision Measurement Technology and Instrument, Tsinghua University, Beijing 100084, People's Republic of China.
Li Qun
LQ
Sun
Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900, People's Republic of China.
Kai
K
Zhang
Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900, People's Republic of China.
Xiao Yang
XY
Hu
Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900, People's Republic of China.
Shan
S
Zhou
The Center of Measurement and Test, China Academy of Engineering Physics, Mianyang 621900, People's Republic of China.
De
D
Xu