Heat Straps monitor / External heater of the separator line

Heat Straps

Often, heat straps are put on the exterior of the shells below the large ISO-200 Tee and above the blue magnet dewar. This helps to keep the electronics from freezing, and when using a Teflon O-ring it helped to not let it freeze. The temperature difference between the inside and outside of the shells with the Teflon O-ring should be kept as low as possible, preferably within less than 20 degrees C of each other. If the temperature difference increases too much, that will cause the o-ring to fail and cause a dangerous vacuum leak/shells failure event.

Starting in August 2020, we have new shells where the Teflon o-ring has been replaced with copper CF flanges, so it is hoped that we will not have to worry as much about another leak event.

Even still, the heat straps can be used to limit the amount of frosting on the top of the shells to avoid getting water/ice on the electronics. Ideally, the heaters should be connected to a thermocouple and PID loop controller so that they can be well-controlled. The set temperature should not be higher than 10-15 C above room temperature, and the ideal set temperature should be between room temperature and the freezing point of water.