4 ms·

Professor Edgerton’s Atomic Camera (2006)

33 points by benbreen 4y ago

adg001 4y ago
Charles Wyckoff, who worked for EG&G (Edgerton, Germeshausen and Grier), showcasing a rapatronic camera and its peculiar shutter. [1] [1] https://youtu.be/h0gXivjfh8o https://youtu.be/h0gXivjfh8o
tecleandor 4y ago
As of today it should be easy to do a relatively cheap rapatronic-like camera with LCD film. The basic principle is more or less the same: two linearly (?) polarized sheets at 90° that block all the light going through, and a sheet/material in the middle that rotates 90° the light polarization when an electric current is applied. Some of those glass windows that can obscure instantly work with this technology. https://en.m.wikipedia.org/wiki/Liquid-crystal_display https://en.m.wikipedia.org/wiki/Liquid-crystal_display What I don't know is the speed of polarization rotation for liquid crystals (compared to a Kerr cell) that would define the minimum "obturation" speed available.
- adg001 4y ago
  A back of envelope calculation for the shutter speed of a Pimoroni LCD shutter [1] suggests 1/15s is the fastest speed available. [2] [1] Pimoroni LCD shutter [Not available any longer ] https://shop.pimoroni.com/products/lcd-shutter https://shop.pimoroni.com/products/lcd-shutter [2] Testing the amazing Pimoroni LCD shutter https://youtu.be/i3GCfAtdZYI https://youtu.be/i3GCfAtdZYI
  - tecleandor 4y ago
    I've never researched much about this, but this company claims that TN shutters can do up to 100hz and "liquid crystal pi cells" can do 1000hz. http://www.liquidcrystaltechnologies.com/products/lcdshutters.htm http://www.liquidcrystaltechnologies.com/products/lcdshutter... This is interesting, I might expend the afternoon reading about it Edit: Related 6 years old EE Stack Exchange post: https://electronics.stackexchange.com/questions/276014/characteristics-of-tn-lcd-shutters-light-valves https://electronics.stackexchange.com/questions/276014/chara... Also this company sells a pi-cell shutter with "50 microsecond rise time 1.3 millisecond fall time" for ~$200USD. I have to calculate the refresh for that : https://boldervision.com/liquid-crystals/pi-cell-shutter/ https://boldervision.com/liquid-crystals/pi-cell-shutter/
- LightRailTycoon 4y ago
  Auto-darkening welding helmets claim 40 microseconds.
  - tecleandor 4y ago
    That seems to match with a shutter vendor that says "50 microsecond rise time 1.3 millisecond fall time". So I guess 'rising' is going dark, and 'falling' is going clear. Or 'rising' means changing the natural state of the crystal (thus rotating 90° the polarization), and 'falling'... well, falling back to the natural resting state. It makes some sense that falling back when unenergized is slower than rising. Now it'd be interesting to know what happens during rise and fall time. Progressive linear polarization? Waiting time until the crystal reacts?
- dekhn 4y ago
  See https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=8166 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=81... for examples of modern LCD shutters. They have closing times that are in the hundreds of microseconds, so they are not really replacements for ultra-short exposures. But they are "cheap".
denton-scratch 4y ago
I'd like to see some more photos of the first moments of a nuclear fireball. You sometimes see video of a nuclear blast; but the first frames just show a ball of plasma that looks like an opaque white cloud. The light from the blast washes out everything else; there's no sense of scale. Is that 100 feet across, or a mile across? And how long ago was the blast? Slo-mo video, with a size scale and a clock, would be fascinating. But a sequence of rapatronic stills would be very interesting.
- adg001 4y ago
  > But a sequence of rapatronic stills would be very interesting. You have a short sequence of stills in the Wyckoff's footage linked somewhere else here. Rapatronic cameras – Wyckoff explains – where typically mounted in a rack of six, where each captured a single frame.
- matthewmcg 4y ago
  There’s a great sequence here: https://1.bp.blogspot.com/-CZhjFVVqx6c/TcbXi9tKg8I/AAAAAAAAAkk/5zlAxpQ4DEs/s1600/Teller+Light+2.jpg https://1.bp.blogspot.com/-CZhjFVVqx6c/TcbXi9tKg8I/AAAAAAAAA... You can actually see the x rays causing the air outside the bomb casing to glow before the casing is destroyed by the expanding fireball. More technical info here: https://cinergie.unibo.it/article/view/10328/11419 https://cinergie.unibo.it/article/view/10328/11419
- acidburnNSA 4y ago
  There are a few in here https://www.atomicarchive.com/media/photographs/testing/us/index.html https://www.atomicarchive.com/media/photographs/testing/us/i...
rkagerer 4y ago
Here's a photo it took nanoseconds after an atomic donation, with some antenna masts in the background for scale: https://i.imgur.com/nO9gqQp.jpg https://i.imgur.com/nO9gqQp.jpg
- deleted 4y ago
  [deleted]
mikewarot 4y ago
One interesting tangent to those explosions, is the "double flash" that happens due to the physics of the shell heating rapidly, then obscuring the explosion, then being outrun by the contents. Even when nations conspire in secret, such explosions can be detected from space.[1] [1] https://en.wikipedia.org/wiki/Vela_incident https://en.wikipedia.org/wiki/Vela_incident
deleted 4y ago
[deleted]

33 points by benbreen 4y ago

Charles Wyckoff, who worked for EG&G (Edgerton, Germeshausen and Grier), showcasing a rapatronic camera and its peculiar shutter. [1] [1] https://youtu.be/h0gXivjfh8o https://youtu.be/h0gXivjfh8o

tecleandor 4y ago

As of today it should be easy to do a relatively cheap rapatronic-like camera with LCD film. The basic principle is more or less the same: two linearly (?) polarized sheets at 90° that block all the light going through, and a sheet/material in the middle that rotates 90° the light polarization when an electric current is applied. Some of those glass windows that can obscure instantly work with this technology. https://en.m.wikipedia.org/wiki/Liquid-crystal_display https://en.m.wikipedia.org/wiki/Liquid-crystal_display What I don't know is the speed of polarization rotation for liquid crystals (compared to a Kerr cell) that would define the minimum "obturation" speed available.

adg001 4y ago
A back of envelope calculation for the shutter speed of a Pimoroni LCD shutter [1] suggests 1/15s is the fastest speed available. [2] [1] Pimoroni LCD shutter [Not available any longer ] https://shop.pimoroni.com/products/lcd-shutter https://shop.pimoroni.com/products/lcd-shutter [2] Testing the amazing Pimoroni LCD shutter https://youtu.be/i3GCfAtdZYI https://youtu.be/i3GCfAtdZYI
- tecleandor 4y ago
  I've never researched much about this, but this company claims that TN shutters can do up to 100hz and "liquid crystal pi cells" can do 1000hz. http://www.liquidcrystaltechnologies.com/products/lcdshutters.htm http://www.liquidcrystaltechnologies.com/products/lcdshutter... This is interesting, I might expend the afternoon reading about it Edit: Related 6 years old EE Stack Exchange post: https://electronics.stackexchange.com/questions/276014/characteristics-of-tn-lcd-shutters-light-valves https://electronics.stackexchange.com/questions/276014/chara... Also this company sells a pi-cell shutter with "50 microsecond rise time 1.3 millisecond fall time" for ~$200USD. I have to calculate the refresh for that : https://boldervision.com/liquid-crystals/pi-cell-shutter/ https://boldervision.com/liquid-crystals/pi-cell-shutter/
LightRailTycoon 4y ago
Auto-darkening welding helmets claim 40 microseconds.
- tecleandor 4y ago
  That seems to match with a shutter vendor that says "50 microsecond rise time 1.3 millisecond fall time". So I guess 'rising' is going dark, and 'falling' is going clear. Or 'rising' means changing the natural state of the crystal (thus rotating 90° the polarization), and 'falling'... well, falling back to the natural resting state. It makes some sense that falling back when unenergized is slower than rising. Now it'd be interesting to know what happens during rise and fall time. Progressive linear polarization? Waiting time until the crystal reacts?
dekhn 4y ago
See https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=8166 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=81... for examples of modern LCD shutters. They have closing times that are in the hundreds of microseconds, so they are not really replacements for ultra-short exposures. But they are "cheap".

denton-scratch 4y ago

I'd like to see some more photos of the first moments of a nuclear fireball. You sometimes see video of a nuclear blast; but the first frames just show a ball of plasma that looks like an opaque white cloud. The light from the blast washes out everything else; there's no sense of scale. Is that 100 feet across, or a mile across? And how long ago was the blast? Slo-mo video, with a size scale and a clock, would be fascinating. But a sequence of rapatronic stills would be very interesting.

adg001 4y ago
> But a sequence of rapatronic stills would be very interesting. You have a short sequence of stills in the Wyckoff's footage linked somewhere else here. Rapatronic cameras – Wyckoff explains – where typically mounted in a rack of six, where each captured a single frame.
matthewmcg 4y ago
There’s a great sequence here: https://1.bp.blogspot.com/-CZhjFVVqx6c/TcbXi9tKg8I/AAAAAAAAAkk/5zlAxpQ4DEs/s1600/Teller+Light+2.jpg https://1.bp.blogspot.com/-CZhjFVVqx6c/TcbXi9tKg8I/AAAAAAAAA... You can actually see the x rays causing the air outside the bomb casing to glow before the casing is destroyed by the expanding fireball. More technical info here: https://cinergie.unibo.it/article/view/10328/11419 https://cinergie.unibo.it/article/view/10328/11419
acidburnNSA 4y ago
There are a few in here https://www.atomicarchive.com/media/photographs/testing/us/index.html https://www.atomicarchive.com/media/photographs/testing/us/i...

rkagerer 4y ago

Here's a photo it took nanoseconds after an atomic donation, with some antenna masts in the background for scale: https://i.imgur.com/nO9gqQp.jpg https://i.imgur.com/nO9gqQp.jpg

deleted 4y ago
[deleted]

mikewarot 4y ago

One interesting tangent to those explosions, is the "double flash" that happens due to the physics of the shell heating rapidly, then obscuring the explosion, then being outrun by the contents. Even when nations conspire in secret, such explosions can be detected from space.[1] [1] https://en.wikipedia.org/wiki/Vela_incident https://en.wikipedia.org/wiki/Vela_incident

deleted 4y ago

[deleted]