Development of thermostatic unit for new magnet power supply at J-PARC MR

In J-PARC Main Ring (MR), we plan to shorten the driving cycle from 2.48 sec to about 1 sec for higher beam power. To achieve this, replacement of the power supplies of main magnets is mandatory. The digital control system is adopted to the power supply controller. This is because the digital control system enables us to implement complex algorithm into the controller and reproduce its configuration. In case of the digital control, the stability of the current measurement decides the performance of the controller. To maintain stable operation of our high intensity beam, the stability of the current measurement needs to be at ppm level. This needs the temperature control of the A/D convertor and its surrounding circuit (A/D board). We have developed a thermostatic unit for the A/D board and successfully control the temperature around the A/D board within our requirement level. In this article, we describe the details of the developed thermostatic unit. (author)