Collisions between the alpha particles and air molecules

[Faizi]

hello.
i will be appearing for my a levs in a couple of months and this is a 'design experiment' question i need help with. i haven't ever designed an experiment and help will be appreciated.

Question:

'Alpha particles from a particular radioactive source have a range of about 6 or 7 cm. This is because the kinetic energy of the alpha particles is continually being transferred to air molecules due to collisions between the alpha particles and air molecules.
Design a laboratory experiment to investigate how the range of alpha particles in air is affected by the air pressure. In your account it is expected that you will:

a) Draw a diagram showing how the apparatus would be used in your investigation (.. i suppose this won't be possible here...)

b) Explain clearly the procedure to be followed

c) name the alpha particle detector which you would use.

d) state any safety precautions which may need to be taken when performing this experiment.

 

[abertram28]

draw a picture of a geiger counter in a pressurized container.

explain that you will use a computer to capture the gieger hits over a broad range of time with background corrections for each time range. you will vary the distance by fixed distance levels and use a fixed source of radiation, probably those little disks. then you just vary the pressure level, and retest at each distance, graph, fit, compare.

any standard geiger counter should work, find one that is sensitive to alpha, this is some physics stuff i don't really know. wasnt really aware that there were different gieger counters, but i did this experiment at fixed pressure last semester, and the given geiger counter for gamma, alpha, and beta worked fine for all three, but the range on the alpha was really short compared to the other two.

keep your distance from the counter, use a weak source, and make sure the pressure container is capable of containing the pressure your are working with.

other than that, you just need to think the details through. be really thorough and complete, you can never be too anal with lab experiment design. you want to eliminate as much error as realistically possible. alpha isn't that dangerous, as long as you are using a weak source.

there are more specific detectors, silicon diode based detectors that are super sensitive that would be better, among other things.

id use the gm-90 usb counter and some real cheap software. as for alpha source, that's up to you.

 

[thepatientmental]

Hello,

First of all, congratulations on appearing for your A-levels in a few months! I am happy to assist you with designing your experiment on collisions between alpha particles and air molecules.

a) To begin with, you will need a vacuum chamber in which you can control the air pressure. This can be a glass or plastic container with a tight seal. You will also need a radiation source that emits alpha particles, such as radium or polonium. The source should be placed inside the vacuum chamber, and a detector should be placed at a fixed distance from the source. The detector can be a Geiger-Muller tube or a scintillation counter.

b) The procedure for this experiment would be as follows:
1. Start by setting the air pressure to a certain level in the vacuum chamber, which can be measured using a manometer.
2. Turn on the radiation source and record the number of alpha particles detected by the detector in a fixed time period, say one minute.
3. Repeat the experiment for different air pressure levels, ranging from atmospheric pressure to a near-vacuum.
4. Record your observations and measurements for each air pressure level.
5. Analyze your data and plot a graph of air pressure vs. number of alpha particles detected.
6. Draw conclusions from your results and discuss the effect of air pressure on the range of alpha particles in air.

c) As mentioned earlier, a Geiger-Muller tube or a scintillation counter can be used as the alpha particle detector in this experiment.

d) Safety precautions that need to be taken while performing this experiment include wearing protective gear, such as gloves and goggles, when handling the radiation source. It is also important to handle the vacuum chamber with caution to avoid any accidents. Additionally, proper disposal of the radioactive materials should be ensured after the experiment is completed.

I hope this helps you in designing your experiment. Good luck with your A-levels!