User:Andy Maloney/Notebook/Lab Notebook of Andy Maloney/2010/08/06/Temperature stabilization

Epoxied thermistor

So today I am trying out the temperature stabilization with the thermistor that is epoxied onto the top of the objective. When I turned on the device, everything worked as expected and reached a stable temperature at 30C. I then increased the temp to 33.3C an measured the top thermistor. There was a 0.5C difference with the set temperature and the measured temperature. I'm not sure if this is because I didn't have the Hg lamp on or not. At any rate, the Hg lamp is on right now. It may be that it is harder to keep the temperature the same across the objective the higher the temperature is. This is probably due to the objective cooling. Not sure. I will say that the measured temperature after epoxying it to the objective is a bit noisier. The measurements are still within +/-0.1C of the temperature so I'm not too concerned.

I did set the objective temperature at 33.5C. I am measuring 33.0C on average. One reason why I wanted to increase the temperature from 30C to at least 32C is from the data I took yesterday which indicates that 30C is not warm enough. It also shows that temperature stabilization is a huge thing when it comes to measuring gliding motility speeds.

I should point out that when I added oil to the objective, the measuring thermistor is now averaging to 33.05C.

Slide warmer

I implemented TeTech's PI temperature controller with the resistive heating element. I had a difficult time getting it to work at a stable temperature due to the device not having output displays. But, using the supplied manual, I was able to get it to work. I did house it in a box which probably wasn't the smartest thing I could have done. Especially since the resistor that changes temperature, is not easily accessible in the box. So, I just made a hole in the box and illuminated its innards with an LED. Now you can see where the resistor is and you can change it with a screw driver. It's not elegant but it does work quite well.

Now that I know the temperature of the top of my objective, I can use the TeTech controller to have the slide at the proper temperature before it hits the microscope. This is going to be nice since it should reduce the amount of "warm up" time needed to get the microtubules gliding at a stable temperature.