$B!!(JThis paper describes the development of highly accurate detecting technologies to measure the voltage and the power, (which are the fundamental units,) of a radio frequency wave and a high power continuous wave C0₂ laser. The thermo-sense mechanism which requires many considerations, has to be designed so that it may respond to an electro-magnetic wave with high sensitivity. We have developed a thermistor mount, a thermo-couple type thermal converter, an alumite cone calorimeter, and a quartz-thermal type direct converter.
$B!!(JIn Chapter 1, the process of development of a thermistor mount for the radio frequency voltage standards is described. The thermistor mount was designed so that the residual contribution of the leads in the thermistor was eliminated when used in the UHF range. The output voltage of the thermistor bridge was measured with an accuracy of 0.3%over 0.1-1 V for frequencies up to 1.5 GHz. The output voltage agreed with the voltage derived from the power standards and impedance standards within the accuracy limit. Subsequently, this method could widen the frequency range from 10 MHz-500 MHZ to 10 MHz-1.5 GHz.
$B!!(JIn Chapter 2, a description of a developed thermal converter consisting of a thermo-couple as a RF current-sensor and a 50 Ohm disk-type resistor is given. This is designed for accurate determination of the magnetic field from a Standard loop antenna ; the incident power on the antenna had to be measured exactly. In comparison with a RF voltage standard, the values agreed within 0.2%(I%(J The achievement was transferred to Thailand Institute of Science and Technology Research, and the technology has been used as the national standard in Thailand. It has also been adopted as a secondary standard at J. M. I. in Japan.
$B!!(JChapter 3 describes a developed calorimeter which was designed to measure the power of a high power CW C0₂ laser. This consists of a double cone-shaped optical absorber which is made of alumite and cooled with water, a quartz thermo sensor with high resolution, a water flow meter, and a data processor to calculate power of the laser. The optical absorber has a response time of less than 11 seconds. A Theoretical discussion is given on the possible causes of errors. The calculations about optical absoption, thermal conduction, and radiation give an estimated uncertainty in category B with a standard deviation of 0.2%at 10 kW.
$B!!(JChapter 4 proposes a new power mount as a digital sensor which is based on the principle of an oscillation frequency shift caused by a minute temperature rise in a quartz oscillator. The quartz oscillator has a certain cut angle which enables it to have a strong dependence of temperature on oscillation frequency, and an electrode which functions as an energy absorber of radio frequency waves, microwaves, and laserlight. The sensitivity is 34 Hz/mW. A quartz sensor, which we have called a "light through type", has also been developed. This has the advantage of a wide dynamic range from several micro watts to several tens of watts for detecting laser power.
$B!!(JChapter 5 gives the main conclusions of this report.