Explain+the+process+of+preparing+and+ashing+the+fish

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[[BB's 2009 - '10 Logbook|BB's Logbook

]] Explain the Process of Preparing and Ashing the Fish

Why preparing the samples is needed

The step of preparing the samples is necessary to make handling the fish simpler and more convenient. If I were to skip this step I would have to deal with many more problems. I would have to worry about the fish defrosting or else going bad. I would have to worry about cleaning up the fish mess after every experiment and dealing with the fish smell. By preparing the samples and ashing them I do not have to deal with any of those problems. By ashing each fish there is no smell, minimal cleanup, and a much improved shelf life that does not need any special care as in freezing.

Step 1:

The first step in the pre-experiment preparing process is acquiring a fish. I have used fish in the local area as samples. I have two fish that have experimented with so far. The first was a fresh salmon from the local grocery store, Martain's grocery. The second was a fresh caught blue gill that was caught in a lake just north of here. Some of the fish I had to buy. The blue gill was kindly donated by a local fisherman. Once the fish were in my possession they were put in the freezer so they would keep until I could get to the next step.

Step 2:

The next step is the actual ashing of the fish. This step is most important in simplifying the PIXE/XRF experiment. The ashing makes it so the fish does not go bad and that cleanup is much easier. I was able to use an ashing oven in the natural science building. An ashing oven is basically an oven that can get really hot. The typical setting I use to ash the fish, as sugested by my mentor, is ashing at 550 degrees Celsius for three hours. Mike said that should be enough time for the whole fish to burn into ash. So far it has worked well on those settings.

Step 3:

This last step has to do with preparing the ash for the PIXE and XRF experiments. There is not much that is needed in the way of preparing for XRF. Where I need to put the substance to be experimented with is a flat horizontal surface. I can use a plastic dish to hold the ash while XRF is running. PIXE is more complicated because there is a vertical mount. I ended up taking some ash and stuffing it into the head of a screw. I then put the screw into a block of Styrofoam. This enabled me to position the ash in front of the PIXE beam.

Problems with ashing

I have had two problems with the ashing process. For one of the fish, the jar shattered while in the oven. This was because I put the fish in the jar when it was still frozen. The temperature difference caused the jar to shatter. This can be avoided by letting the fish defrost before putting it in the jar. The second problem is that you can not write anything on the jar that go into the ashing oven; the writing ends up burning off. I have been ashing the fish one at a time and keeping a detailed lab book to keep track the fish.