jUNE S M T W T F S
 jULY S M T W T F S 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

June 02, 2009:

First began working with the ellipsometer. Alignment of the ellipsometer as well as cleanliness of my glassware is a critical part of

collecting accurate and reproducible data. My cleaning technique involves glass etch which consists of hydrofluoric and nitric acids.

This process actually “eats” away about an angstrom of glass inside the bottles removing any filth inside the glass.

June 03, 2009:

I spent today looking for some more of the bottles we use in ellipsometry. Once found, I spent the rest of the day using the glass etch

on each of these bottles.

June 04, 2009:

It is important to only fill each bottle exactly half-way to get accurate readings on the ellipsometer. In order to find the half-volume

inside each of my bottles, I have filled each bottle with water and weighed the amount of water used to fill bottle. Using the density of

water, I am able to determine the half-volume of each bottle.

June 05, 2009:

I spent today taking data samples of pure water in order to have a value to compare our solutions to.

Upon the suggestion of Dr. Law, I made a stock solution of 1.4M stock solution in hopes that it will be easier to have on solution already

made rather than making a fresh solution every day. I began collecting samples of various concentrations of NaI solutions.

June 10, 2009:

My data collected yesterday is not reproducible today and I am getting a value of 0 for the imaginary coefficient of ellipticity,  Im(Rho), at

the Brewster angle, which is impossible and leads us to believe something is wrong in either my alignment or something else.

June 11, 2009:

I am checking the water values in every bottle again to determine if we get consistent results. We do not get consistent results so it is

assumed that my bottles are unclean.

June 12, 2009:

I first cleaned my bottles with soap and water, and then checked for consistent results with pure water. This yields inconsistent results

once again. Next we try to sonicate the bottles with soap and water and being sure to rinse the bottles very well. Again, we see

inconsistent results. As a last resort the bottles are glass etched, and fairly consistent values are seen.

Data is collected again for the NaI solutions first of a 1.1M concentration then with a .11M concentration. Both of these data collections

contain some results with zero at the Brewster angle, so again it is assumed something is wrong.

June 16, 2009

The bottles are cleaned, and new solutions are made in order to be sure the zero values are not due to filth in the bottles. Again values of

zero at the Brewster angle are found.

June 17, 2009:

Tests are done on the ellipsometer in order to make sure the ellipsometer is working correctly. The tests prove the ellipsometer is working

fine.

June 18, 2009:

A brand new stock solution is made and still the results are inconsistent.

June 19, 2009:

It is realized by Dr. Law that our glass bottles act as a lens thus causing our laser beam to diverge. A lens is put in between the birefringence

modulator and the solution.

With the lens in place, data is collected once more for pure water samples.

June 23, 2009:

Water values are again inconsistent and do not match the accepted value. Tests are done with our sample of carbon tetrachloride which

is sealed (thus completely clean) and has a known value. These results are consistent and closely match the accepted value, thus determining

that the lens does not have an effect on our values and should not skew the water values nor give such a broad range.

June 24, 2009:

As suggested by Haeng Sub, measurements are taken at various spots on the bottle, and noted whether the reflected beam from the bottle

is bright or dim. This is done in order to see if there is a correlation between bright and dim reflectance and the measured coefficient of

ellipticity value measured. No correlation was determined

June 25, 2009:

Glass etched the bottles in the morning.

Upon the suggestion of Dr. Law, the sensitivity on the ellipsometer is changed to 10mV rather than 100mV. This gives the most accurate

Rho(Im) value so far with the smallest deviation. We now have an accepted water value.

June 30, 2009:

Measurements are taken for 1.1M NaI and .11MNaI solutions. Again, the data has a broad range and even exceeds the water value.

July 1, 2009:

Since the label on the NaI salt says to keep the salt out of the light. It is hypothesized that the salt solutions also need to be made in the

dark. This seems to prove true for the first sample 1.15M NaI solution, however the results are not reproducible. The following week

is dedicated to obtaining reproducibility. No reproducible results are reached.

Since there is limited NaI salt left, and it is difficult to keep the salt in complete darkness, I switch to working with NaBr, the next largest

and polarizable salt. The first solution made is 1.0M NaBr. When tested, the water value is obtained. So a 2.0M NaBr solution is made and

yields the same result. Finally, a 3.0M solution is made however, the same scenario occurs. The solution is left untouched for 2 hours, and

when the Rho(Im) value is measured again, the result is negative. After two more hours the results appear more negative. It is hypothesized

that the solution cannot be shaken  just prior to measurements as it requires time to come to equilibrium.

July 10-12, 2009:

Our equilibrium hypothesis is reinforced by data collected throughout the past three days, and measurements will be taken in order to determine whether or not there is a dependence on concentration.

July 13, 2009:

I begin collecting data on the 2.25M NaBr solution to determine concentration dependence of the equilibrium time.