title: Research on calorimeter for high-power microwave measurements.
abstract: Based on measurement of the volume increment of polar liquid that is a result of heating by absorbed microwave energy, two types of calorimeters with coaxial capacitive probes for measurement of high-power microwave energy are designed in this paper. The first is an "inline" calorimeter, which is placed as an absorbing load at the end of the output waveguide, and the second is an "offline" calorimeter that is placed 20 cm away from the radiation horn of the high-power microwave generator. Ethanol and high density polyethylene are used as the absorbing and housing materials, respectively. Results from both simulations and a "cold test" on a 9.3 GHz klystron show that the "inline" calorimeter has a measurement range of more than 100 J and an energy absorption coefficient of 93%, while the experimental results on a 9.3 GHz relativistic backward-wave oscillator show that the device's power capacity is approximately 0.9 GW. The same experiments were also carried out for the "offline" calorimeter, and the results indicate that it can be used to eliminate the effects of the shock of the solenoid on the measurement curves and that the device has a higher power capacity of 2.5 GW. The results of the numerical simulations, the "cold tests," and the experiments show good agreement.
authors.affiliation: Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024, China.
authors.forename: Hu
authors.initials: H
authors.lastname: Ye
authors.affiliation: Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Ning
authors.affiliation: Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024, China.
authors.forename: Wensen
authors.initials: W
authors.lastname: Yang
authors.affiliation: Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024, China.
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024, China.
authors.forename: Zhengfeng
authors.initials: Z
authors.lastname: Xiong
authors.affiliation: Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Yang
authors.affiliation: Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Yan
authors.affiliation: Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024, China.
authors.forename: Xinhong
authors.initials: X
authors.lastname: Cui