Building scientific apparatus

What Hacker News says

1. patwillson22Jul 2020
   Alright here it goes.

   What we're basically doing is using thermal evaporation to lay down thin films of metal on top of each other in a high vacuum environment. We're then patterning the cell with a fiber laser to produce the cell traces and patterns needed to cell size.

   Here's an example of system that does what i've just described in the context of creating CDTE cells. Note that it doesn't use a laser to create the cell divisions but rather uses a conductive ink and sand blasting.

   https://avs.scitation.org/doi/abs/10.1116/1.4941071?journalC....

   I thoroughly analyzed their design and I have copied some aspects of their design while avoiding many of the flaws that significantly limited it's practically and efficiency. Here's a quick summary of the design changes and flaws that I found.

   For one, the design specified in the paper can barely reach high vacuum which is a requirement for producing cells of reasonable efficiency.

   One major improvement I'm working on is a system that allows for automatic changing depostion powder inside that chamber instead having multiple chambers for each layer of depostion powder.

   The advantage of this approach is that miniaturizes the chamber size significantly, making closer to the size of something that could fit in the back of your car then something that needs a dedicated room or floor for.

   I've also looked carefully at how im going to achieve high and maybe even ultra high vacuum. And in that regard I think I've made some significant strides.

   My design achieves high vacuum in three stages, the first is through a simple ventri pump and the second is a sorption pump which has been redesigned based on a old paper I found here(). The last stage uses something called a non-evaporable getter pump.

   Experienced vacuum engineers might initially be baffled of choice of pumps I am using. As they are normally considered too slow for the type of operation that the chamber is being put through.

   However, the downsides of the speed of these pumps can be mitigated by three measures. (1)Building a chamber that can go through bakeout(which removes contaminates and reduces pump down time) (2)Designing a chamber with metal-to metal seals and low leak rate. Lastly the obvious principal of making the chamber volume and surface as small as possible while making the size of the pumps large.

   I've barely scratched the surface here but I think this should give you a rough idea of what I'm doing. I really dont think this stuff is hard as how it's made out to be.

   Here some resources that really have really helped out so far.

   -Building Scientific Apparatus a book that should give you a broad overview of things you need to know

   -vacuum sealing techniques alexander roth Extremely exhaustive in the amount of information of about, valves, and just general construction of the chamber. The book is really old but everything still stands and it's honestly better than most of the stuff i've found online.

   Blogs by this guy https://www.normandale.edu/departments/stem-and-education/va....

   Really good introduction to basic stuff you need to know and decisions you need to make.

   If anyone has any questions further I would be happy to answer them.

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2. sitkackFeb 2015
   Thank you! I have been looking for this book, I thumbed through a copy in a lab I visited.

   Another excellent book in the same vein is, "Building Scientific Apparatus" - http://www.amazon.com/Building-Scientific-Apparatus-John-Moo... the second edition can be had for a song.

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3. tomkinstinchAug 2012
   For spectroscopy, I'd go to the online handbook put out by Richardson Gratings:

   http://gratings.newport.com/information/handbook/handbook.as...

   For a textbook, this one is pretty good:

   http://www.amazon.com/Introduction-Spectroscopy-Donald-L-Pav...

   For optics, Hecht is the classic text:

   http://www.amazon.com/Optics-4th-Edition-Eugene-Hecht/dp/080...

   I'd suggest Keating though, since it is a more comprehensive overview and includes things like the human visual system and some basic math review:

   http://www.amazon.com/Geometric-Physical-Visual-Optics-2e/dp...

   For instrument design in general, these books are outstanding:

   http://www.amazon.com/Building-Scientific-Apparatus-John-Moo...

   http://www.amazon.com/Optical-System-Design-Second-Fischer/d...

   Of course, any understanding of spectroscopy should include some background of the physics behind what you're measuring. Any modern physics book would be fine: Krane, etc.:

   http://www.amazon.com/Modern-Physics-Kenneth-S-Krane/dp/1118...

   Haven't tried this one, but it looks cool:

   http://www.amazon.com/Spectroscopy-Reading-Stellar-Practical...

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4. JugurthaNov 2020
   For any reader of this: if you understood apparatus in the scientific sense, there is a book titled "Building Scientific Apparatus" by Moore and Davis.
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