posted by: lrose
June 29 –This is the apparatus that Becky and I built to irradiate the samples. the chamber that hangs down is where the Polonium and the sample are housed. The nitrogen gas is passed through the tube-like top chamber and the glove is attached to pressurize the chamber to insure that nitrogen fills the chamber. we put a whole in the glove for the nitrogen to slowly escape. 
posted by: lrose
So much trouble scanning the samples.
June 24
We investigated the optimum amount of time to expose the sample to the Polonium. We found that 1 hour was about right. But still we are having trouble getting the STM to image the scan without crashing. Becky suggested we get Val to scan a sample on the AFM to get a better idea what the entire surface looked like to get parameters for scanning.
Val agreed to scan a sample. Lauren Chorny, our high school student research associate, was going to learn to use the SEM and AFM with these samples. We made her a sample of gold irradiated by Polonium. When she scanned it, instead of the craters we thought would be there, we discovered structures that rise above the surface.
This caused us to ask many more questions. What cause the blobs on the surface? Why were some larger than others? Why weren’t there craters from the alpha particles hitting the surface? Would there be more if the sample was irradiated longer? Were these caused because Gold is rather soft and can be easily melted?
Dr. Kadel suggested we try irradiating Carbon. It is more rigid and not as easy to melt. We might see craters then instead of hills.
posted by: lrose
this summer we are trying to find out what happens to surface atoms when they are irradiated. We need to know what the damage looks like, how big an area is changed, what the margins look like and how much time is optimum to expose a sample to be able to learn these things.
There are a couple of interesting applications for this information. One is with living cells. How much of a cell is damaged by alpha particles? Can it be directed to interact in specific areas? Can we focus the distruction so it effectively removes one layer of atoms?
More tomorrow on what has already been done.
