|
|
Thread Tools | Display Modes |
#2
|
|||
|
|||
CCD charge transfer
[Moderator's note: Apologies for posting this so late; I had overlooked
it before leaving for holiday. -P.H.] On Sunday, July 31, 2016 at 3:31:35 PM UTC-4, Martin Brown wrote: On 01/06/2016 05:00, wrote: On Friday, May 27, 2016 at 1:15:25 PM UTC-4, Tom Roberts wrote: On 5/20/16 5/20/16 - 10:17 PM, wrote: If a charge packet in a CCD pixel is accelerated out of a pixel (in some direction) due to charge transfer, I wish to know what would be the median frequency of photons emitted from the pixel array (simultaneously) by this acceleration; and what then would be the corresponding median charge packet velocity? Most of the electromagnetic noise would be in the RF band at around the readout clock frequency and odd harmonics give or take a bit of jitter. The CCD should not notice it at all. In a CCD being read out, the radiation emitted is completely negligible, because the individual electrons are moving so slowly and their acceleration is correspondingly very very small. That's the microscopic explanation; macroscopically the currents are very small as are the distances involved, so the radiation is (very small) squared. Tom Roberts I appreciate the clarification. I'm trying to account (in theory) for a source of evanescent waves (fringes) across the pixel array, with frequencies quantized as nu_n = n(nu_o), where n is integer quantum mode n=(NdP_n/h), N is array dim in unit pixels, d is pixel dim. P_n = (h/Nd)n is momentum, h is Planck's constant, nu_o is detector fundamental frequency nu_o = (c/d)/N and c is light velocity in vacuum. I think you need to a post a picture somewhere to demonstrate the effect that you are seeing, but my first guess would be either some kind of Moire fringing due to inadequate oversampling of a broadband image or an interaction between the regular structure of the CCD pixel layout and monochromatic light. What could "diffract" during charge xfer/readout? IR photons from the readout amplifier is one possibility typically leading to a warm corner with faint radiating lines away from it. Modern CCDs are very much better in this respect than early ones. -- Regards, Martin Brown 160802 Thanks for the notes. Let me digress on this: since the effect is not visible in the output of the CCD, but rather a result of computational processing of an image, I'm a bit skeptical the effect is "real," and if it is, that it's of practical use. My experiment may be the noise. That said, I think this might be of general interest, and independently reproducible. With the input image dim. N fixed, N=512, I've run image data from several detectors with pixel dim. d ranging 6.8 - 21.0 microns. Overall, the frequencies, plotted versus counts, yield resonances at 1.25 THz +/- 0.25 THz. So the fringes are sub-mm. The average visibility is 0.90. I could send you images via email, if you wish. My best guess at this point (underscore guess), is that I'm "seeing" plasmon modes, non-propagating typically; but I find that changes to the primary source (point or extended), DO appear to couple, evident in certain systematic changes to the statistics of observed phase singularities / topological charges (orbital angular momentum) visible as characterisitic forks in the fringes. It's beyond me to know how conceptually misguided this might be. Best, mark jonathan horn |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
CCD charge transfer | John Heath | Research | 0 | June 4th 16 09:51 PM |
transfer preachs sam | V. W. Nichol | Amateur Astronomy | 0 | August 15th 07 01:42 AM |
transfer | Ed. Ehrenspeck | SETI | 1 | January 5th 05 05:40 AM |
Bielliptic Transfer | Reza | Technology | 4 | August 10th 04 11:31 PM |
SETI WU transfer | Stephen McHaney | SETI | 6 | October 10th 03 12:20 AM |