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Is there any way to recreate this experiment with detectors at home?

I need detectors If I want to recreate the interference pattern. I have a little know-how in electronics so If I need to buy a detector there wouldn't be a problem using it. The thing is I don't know which detector should I use. Can I do this? Is It just too expensive for a DIY project?

Muhamed Krlić
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    We need a lot more info on your design. Do you want to measure visible photons? Radio waves? Electrons? . What's your source (are you aware of coherence requirements)? – Carl Witthoft Feb 25 '14 at 15:40
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    I thought someone's going to ask that. :D Well It's really up to my budget. Realistically I think I want to measure visible photons because I can buy a Laser for a $1 or less. But sure If I need to spend more money on this project I'll do It. – Muhamed Krlić Feb 25 '14 at 17:07
  • I got my inspiration from Dr Quantum video believe it or not :). Since then I started surfing the internet all about double slit experiment. Waves have to be coherent. There's also some math involved in spacing between the gaps to get a good interference patterns. But all this knowledge is a new thing for me and I am willing to learn doing this project. – Muhamed Krlić Feb 25 '14 at 17:22
  • The mind-blowing thing about this experiment is a claim by some people that consciousness is involved in how the particle behaves. Personally I think that It's not true, but I am willing to test this! – Muhamed Krlić Feb 25 '14 at 17:25
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    It's not consciousness which makes particle behave, it's the macroscopic apparatus which measures the particle state. See e.g. this question. – Ruslan Feb 25 '14 at 18:49
  • Yes, thank you. These oversimplified explanations on the internet are mostly misleading. – Muhamed Krlić Feb 25 '14 at 19:44
  • perhaps useful http://www.instructables.com/id/How-To-Make-a-Simple-Double-Slit/ –  Jul 05 '16 at 20:06
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    if you want to measure visible wavelengths, why can't you just use a screen as a detector? (e.g. a wall, sheet of paper) – Wolpertinger Jul 05 '16 at 20:38
  • I'm now curious. If one of the experts out there wanted to do this experiment at home, or use the experiment as a high school demo, how would you do it for a "reasonable" budget (e.g., < $1000, if possible)? – David White Jul 06 '16 at 00:46
  • @Ruslan : The thing that he wants to do is test that hypothesis for himself, independently. Which is actually very good and very much in the spirit of science, and I wish I had had the disposable resources to do things like that myself esp. in my younger years. Given that there are many "authoritative"-seeming pronouncements from various camps from scientifically reasonable to outright quackpot and moreover the judgment of who is who ALSO often given similarly authoritatively, being able to do any direct observation yourself and bypass the partisanship is something I'd think very valuable. – The_Sympathizer Dec 21 '18 at 09:43
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    The real question is why you would want to recreate an experiment that tells you absolutely nothing of interest about quantum mechanics. Can you get yourself a photomultiplier tube and use it at home? Sure. It will set you back by between a couple hundred dollars for a used one and a couple thousand for a brand new one. By the time you are done you will know what a PMT is and does and you will have exactly zero new insight into quantum mechanics. – FlatterMann Oct 27 '22 at 05:13
  • @https://physics.stackexchange.com/users/31684/muhamed-krli%c4%87 I wonder have your ever done the slit experiment? Like you said, you can get a cheap laser and to make it easier just use wires. I use very thin gauge guitar strings. one wire gives you the single slit experiment and two wires give you the double slit. In a dark room you will see the interference just fine. I also designed Slit simulators that do all the math and shows you a graphic. Just input the slit width and separations etc. You can find the simulators on my site at billalsept.com. See Double Slit – Bill Alsept Dec 01 '23 at 07:02

3 Answers3

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The biggest restrictions on detectors are likely to be the light intensity, and the size of one pixel.

The intensity of light that comes through the slits is actually quite small. After all, the slits have to be narrow in order to function. Then you need to go to the screen, spreading out the energy over a wider area. Next, you want to cover the range of intensity in order to see the shape of the pattern. So you need quite a range of sensitivity.

To get details of the pattern, you will want a fairly small size detector pixel. Smaller area means you need more intense light to get signal.

A suggestion: Are you skilled enough to get and install something like a CCD from a digital camera? Probably you don't want to get an actual camera and take out the CCD because it will probably be pretty small for your purposes. To say nothing of destroying the camera. But there are various sizes of CCD devices. And they can be quite sensitive. And they come in a nice grid pattern so your data is automatically divided into locations.

A quick Google found a bunch of things, but I'm not sure where you want to go.

As well, you want to exert care with the light source. Monochromatic is necessary. Intense is good. Consider something like an LED laser pointer type device. You can get them for cheap. Possibly you can get a lens for it that will spread the beam out to the width that is most useful for your experiment.

Alternative: Instead of having the detectors directly receive the light, you could have the light fall on a screen. Then you could use any convenient camera to record the image. A few clever tricks with marks on the screen could give you calibration distances. Then you could extract any information you want from the camera image.

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The question is what exactly it is you would like to observe. If all you are after is an interference pattern, then you could build a double slit experiment with shallow water waves or (classical) laser light. While these are classical waves, the underlying mechanism (maxima and minima due to interference of waves) is exactly the same.

If you insist on using bona fide quantum particles, both, creating a suitable source and a detector will be significantly more complicated. Ditto if you want to create low intensity sources so that you can see single impacts of, say, photons or electrons.

Max Lein
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    Setting up a single photon double slit is next to trivial but it's also fruitless. The diffraction pattern in a double slit if perfectly classical. Counting intensity with photons is a technically useful skill to learn for an experimental physicist (I've done it a lot) but after the first excitements it's just boring tedium because there is absolutely nothing to learn from it other than that a PMT makes "click" more or less randomly. – FlatterMann Oct 27 '22 at 06:47
  • I’m not an experimentalist, but is it really that simple if you wanted to perform a DYI experiment? If you have access to e. g. university lab, I reckon it is, but (going from memory) wouldn’t you need e. g. a photo multiplier, a suitable laser and filters?

    Also, when you write that the PMT clicks “more or less randomly”, that’s precisely the point of the experiment: you confirm the probability interpretation of the wave function, namely that it predicts impacts of discrete particles rather than densities.

     – Max Lein Oct 28 '22 at 07:37
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    PMTs are engineering components. I have never met anybody who has built one (even though I did participate in an experiment that had a very elaborate pulsed laser photocathode electron source) because it is quite a difficult art to build a good one. You simply buy them from Hamamatsu or one or two other companies. You can get the high voltage power supply (called a "base") from the manufacturer as well. That and an electronic counter is all you need. But like I said, if you believe that single photons make any difference, then you simply don't understand the physics of the experiment, yet. – FlatterMann Oct 28 '22 at 07:59
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Cover one slit with a vertically polarized filter and cover the other slit with a horizontally polarized filter. Now you can detect which slit the light passes through, and the double slit interference pattern will disappear, but if you place another polarizing filter at 45 degrees between the slit and the screen, erasing your ability to detect which path the light traveled, the interference pattern will reemerge. Please know that there is a classical and quantum explanation for this.

Lambda
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