Week+of+9-6+and+9-7

9-7-2011 This page is incorrectly titled. I got my dates confused. It should 9-7 and 9-8. I came in today around 3:35 P.M. Today was my first day back in the lab since the summer. Natlaie had me measure the voltages of all the batteries, that were new, before I placed them back into the power supply box for the piezo stack. After I finished taking the voltages, I began to scan with little luck. I scanned Octanethiol on Au(111). The images had little to no definition. There seemed to be a lot of noise on the scans. I only successfully got 2 total scans today, and neither was very interesting or defined. This could be due to a bad tip, a bad sample, or maybe the large amounts of noise in the room. 9-7-11AA- This image shows a few recognizable features but with very bad definition and a lot of noise. media type="custom" key="10389132" 9-7-11AB- This image had very bad resolution and definition. The tip was bad -- most likely blunt-- and there was a lot of noise in the image. media type="custom" key="10389126" 9-8-11

I came in at about 3:40 today. I began the day by scanning a sample of Octanethiol on Au(111). I started scanning but halfway through my first scasn, the STM began to malfunction and I was unable to finish that scan. At about five o'clock Ichanged the tip. The images, "AD"and"AE", improved slightly.There were some features on "AE" so I decided to shoot it with the laser for 45 seconds. I brought the piezoelectric stack power from 45 volts to five volts then back up to 45 volts and I was able to successfully scan again. The after scan, "AF", could have possibly been the same area as the before image. There is a long black crater on the left side in the before image that is curved to the left and there is a long black ridge in the after image that is curved to the right. There is also one black crater in the top middle of both images. In the before image, the crater is more oblong and not as defined but in the after image the crater is more defined and circular. I shot the laser at image "AG" for 45 seconds then let it cool for 1 minute and 30 seconds. I brought the voltage down from 45 V to 5 v then back up to 45 volts after it had cooled. I after image looks nothing like the pre-image. I could have possibly bumped into the wires connected to the sample holder while operating the laser which could have caused this drastic change in area media type="custom" key="10430530" 9-9-11 I did not do anything pertaining to my particular project on this day but I went over to Quarknet and for about an hour and worked on developing some excel skills that will pertain to future MATLAB work that I hope to participate in.