Galvanic corrosion test of water cooled aluminum heatsink

In J-PARC Main Ring (MR), we plan to shorten the driving cycle from 2.5 sec to 1.3 sec for higher beam power. To achieve this, replacement of the power supplies of main magnets is mandatory. A water-cooled heatsink for cooling the IGBT is included as a component of the new power supply. For the purpose of the cost reduction, the aluminum heatsink is used instead of the conventional copper heatsink. A concern in the adoption of the aluminum heatsink is the possibility of the galvanic corrosion since the cooling water is shared with the existing equipments that use copper tubes for the flow channels. Therefore, we conducted a galvanic corrosion evaluation test using aluminum heatsink samples. In this report, we describe the results of expose the flow path and analyzing the condition of the flow path surface. (author)