I keep meaning to get around to showing the world which way up benchcoat should go, for those of you who do not know it is a simple but important matter when working with open radioactive sources. All fumehoods and trays should have a water proof layer at the bottom which has an absorbent side upwards. The idea is that any droplets spilled will be absorbed into the absorbent layer and will not be able to pass downwards.
One way of doing this is to wrap a plastic tray in a plastic bag, then you place in the tray a pad of paper towel like matter. If you spill liquid then it will be rapidly absorbed and will not be mobile. If you leave out the plastic bag then you can contaminate your plastic tray, while if you leave out the paper towel then the contamination can spread when the droplet whizzes around like an ice skater.
Now when I get the chance I will take a postage stamp sized bit of bench coat and I will put 20 or 50 microlitre drops of a blue dye on it, I will repeat the process with a stamp of bench coat the wrong way up. I intend to photograph the event to let you see what happens.
I will warn you that while bench coat might be great for radioactivity work it is not universally good, I would like to point out that while it is a anti-contamination feature it is a pro-fire thing. I have fought petrol fires in chemistry labs, and I have always been lucky that I was fighting a fire which was a pool of fuel on a hard and non flammable surface (tiled floors of fume hoods). I hold the view that a petrol fire on top of a pile of paper or in long dry grass would be a real snake in the grass and a pain in the neck. If you thought I was going to swear in my blog then I have to disappoint you !
Filed under: radioactivity |