Author: Owen

ESEM EDS detector alarm

EDS detectors works like a thermos bottle that slow liquid nitrogen evaporation. When the vacuum in the detector deteriorates the liquid nitrogen that cools the detector evaporates quicker. That is happening in the ESEM detector. We refill the detector twice each week but depending on the timing you might hear an alarm signaling that the liquid nitrogen is low. The alarm is a beep signal every few seconds. Here is the important part of this message – if you hear the alarm let me, Aleister or Liz know so we can refill it.

I will have the vacuum replenished in the summer when ESEM use drops.

Thanks, Owen

Change to FESEM x-ray detector

A persistent complaint about the FESEM EDS system was that it was hard to get enough counts (deadtime) for optimal work. To address this we upgraded the detecting crystal in the EDS detector. Now the crystal is 30 mm2 – it was 10 mm2. Now, for the same beam current, there are additional counts (deadtime). You can get 25-30% deadtime at 20kV with the condenser lens set to 5.

I have the system calibrated and you are free to use the upgraded EDS system.

Let me know if you have questions.