O'Grady, Paul Christopher <cpo@slac.stanford.edu>
Hi,
Our lab uses a number of rayonix cameras. We would like to know the precise pixel size of the MX340-HS described here: https://www.rayonix.com/product/mx340-hs/
MX340-HS | Rayonix, LLC
A very large area, high speed detector for the most demanding X-ray science applications. Consists of a 4 x 4 tiled array of frame-transfer CCD modules, with 340 x 340mm² square active area, tiled without gaps in the imaging area.
www.rayonix.com
. For example, that page says 1x1 binning pixel size is 44um, but 2x2 binning is 89um (which implies 44.5um per pixel). We suspect this is a “rounding” issue. Can you email us the precise pixel size?
Also, that page says the 4x4 array is “tiled without gaps”. Is that because it is a monolithic piece of silicon, or are there actually several different silicon pieces that are mechanically assembled with tight tolerances?
Thank you for any thoughts!
chris
Christine R.A. Muchmore <cram@rayonix.com>
Hello Chris
The actual unbinned pixel size for the MX340-HS detectors is 0.0443 mm.
The accurate binned pixel sizes can be derived from that number by simply multiplying according to binning.
Yes, brochures and promotional materials have rounded numbers.
"Also, that page says the 4x4 array is “tiled without gaps”. Is that because it is a monolithic piece of silicon, or are there actually several different silicon pieces that are mechanically assembled with tight tolerances?"
So these are CCD's mounted on the small ends of fiberoptic glass tapers. The large ends of the fiberoptic glass tapers are squared and fused together (tiled) at the front of the detector, such that the gaps are much smaller than a pixel. There are no silicon pieces to be assembled, this is not a hybrid pixel detector (ASICs bump-bonded to Silicon sensors), instead they are integrating detectors with fast frame-transfer CCDs.
The attached brochure has a small picture of one of those tiled 340mmx340mm FO taper arrays on page 2.
I assume you were using the MX340-HS at BioCARS at the APS. This beamline produces too high a photon count to use with the hybrid pixel array detectors (they would miss photons, because the next one arrives before the pixel has finished processing the last photon). That is why BioCARS has this integrating Detector.
They are trying to install an ePix10k hybrid pixel array (ASICs bump-bonded to the silicon sensors you mentioned) from SLAC, which is also integrating and switches gain when the photon flux becomes too high (much like the Jungfrau from PSI).
Hope this helps,
-Christine
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Christine R.A. Muchmore. Ph.D.
COO
Rayonix, L.L.C.
1880 Oak Ave, Evanston, IL60201
ph:847 869 1548 fx: 847 869 1587
toll-free (US&Canada): 1 877 627 9729
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Christine R.A. Muchmore <cram@rayonix.com>
Chris,
Sorry I just inspected your email address more closely - you must be using the MX340-HS at LCLS.
At an XFEL you obviously also have very high photon rates and need to integrate.
Several ePix10k's must be deployed at LCLS.
Sorry I jumped to the conclusion that you collect at APS...
-Christine
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Christine R.A. Muchmore. Ph.D.
COO
Rayonix, L.L.C.
1880 Oak Ave, Evanston, IL60201
ph:847 869 1548 fx: 847 869 1587
toll-free (US&Canada): 1 877 627 9729
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
O'Grady, Paul Christopher <cpo@slac.stanford.edu>
On Jun 17, 2022, at 3:21 PM, Christine R.A. Muchmore <
On Jun 17, 2022, at 3:21 PM, Christine R.A. Muchmore <cram@rayonix.com> wrote:
Several ePix10k's must be deployed at LCLS.
Sorry I jumped to the conclusion that you collect at APS…
No worries, Christine. Thank you for the excellent answers about the MS340 … very much appreciate that!
Dubrovin, Mikhail
Hi Chris,
Very good progress in understanding of rayonix pixel size!
To close this issue, we need to clarify a couple of other questions.
We also use MX170-HS made of 2x2 tiles https://www.rayonix.com/product/mx170-hs/
Are they made of the same tiles as MX340-HS? Otherwise, we need in their pixel size too.
If stitches between tiles are so precise, we would expect accuracy in coordinate ~1pixel on scale of entire detector.
Corrected pixel size 44.3um relative to used 44um brings a huge coordinate difference on the full detector scale
0.3um * 7680 pixels = 2304 um (or 2.3 mm). Next digit in pixel size gives about order of magnitude smaller correction 0.23mm, that is about 5 pixels. This means that we need in a couple of more digits in pixel size in addition to corrected value 44.3um.
Alternative question would be about precise matrix size. For example, 340x340 mm should be known with precision of 1 pixel. Then pixel size is 340mm/7680 = 44.271 um. Tiny detail might be the size of 340mm is between edges of border pixels or their centers?
Thank you for moderation,
Mikhail
O'Grady, Paul Christopher <cpo@slac.stanford.edu>
On Jun 20, 2022, at 9:25 AM, Dubrovin, Mikhail <
On Jun 20, 2022, at 9:25 AM, Dubrovin, Mikhail <dubrovin@slac.stanford.edu> wrote:
Alternative question would be about precise matrix size. For example, 340x340 mm should be known with precision of 1 pixel. Then pixel size is 340mm/7680 = 44.271 um. Tiny detail might be the size of 340mm is between edges of border pixels or their centers?
Hi Mikhail,
I think your idea above is an excellent one: it feels like the total sensor size (with an error of perhaps 1mm because of the number of significant figures supplied). So pixel size is (340mm += 1mm)/7680 = .044271mm+-.000130mm which feels like it would be high enough precision for us.
I would vote to go with that number, but if you would like to be absolutely certain I’m happy to contact the manufacturer. Let me know what you would prefer,
chris
2022-06-20 3:07 PM
Dubrovin, Mikhail
Chris, It would definitely worth to contact Christine again with these questions.
Precision 340 +/- 1mm is not enough for us.
We need in precision 340.??mm +/- 0.04mm or similar values translated to the pixel size.
Then question about MX170-HS is also important for old experiments.
Mikhail
O'Grady, Paul Christopher <cpo@slac.stanford.edu>
On Jun 17, 2022, at 3:17 PM, Christine R.A. Muchmore <
On Jun 17, 2022, at 3:17 PM, Christine R.A. Muchmore <cram@rayonix.com> wrote:
The actual unbinned pixel size for the MX340-HS detectors is 0.0443 mm.
Hi Christine,
If I could trouble you a little more (if you know the answers). Here at LCLS we’re very interested in precise-as-possible pixel positions. It feels like the best way to calculate that would be from the MX340 sensor dimension of 340mm/7680pixels = 44.271um/pixel. Is it possible to add some significant-figures to the 340mm number? (e.g. 340.27mm?). Might also be good to know if that measurement is pixel-center-to-pixel-center or outer-edge-to-outer-edge (makes a difference of 1 pixel).
And, if possible, would be good to have that number for both MX340 and MX170.
Thank you again!
Christine R.A. Muchmore <cram@rayonix.com>
Paul,
That would not be an adequate way to calculate the pixel position, because it completely ignores the magnification and distortion the FO tapers impose.
The actual CCD has a pixel size around 14 micron. The 340mm number refers to the front of the FO tapers, i. e. The X-ray sensitive surface. Again, there are no silicon sensors like you have with ASICs like the ePix10k (which Rayonix is commercialising together with SLAC).
You would end up with incorrect positions and much too small a pixel size.
The precision is determined by the Xray measurements and calculations Rayonix uses to calculate the pixel position and size.
The details are proprietary.
Please consider that Rayonix has done these distortion corrections for 20 years very successfully. Many institutions have tried to design their own algorithm and ended up with much worse data then they get by using the Rayonix factory calibration. Not just LCLS, but ever scientist at every beamline worldwide wants these numbers as accurate and precise as possible. We are aware of that.
Rayonix is closed for Juneteenth today, but tomorrow I can send you an example of a raw image.
-Christine
2022-06-21 12:14 PM
Dubrovin, Mikhail
Hi Chris,
Good try, but sorry, it was a bad idea to ask "alternative question" about precise value for 340mm. Indeed, she is right CCD panel edges might be quite fuzzy due to tapered shape of the electric field at the very edge. Still, it would be nice to get precise design dimensions of the ONE SEGMENT electrode with capacitors with size "around 14 um". We need in step of these electrodes with precision of 3 digits after the dot like 14.NNN because of huge number of pixels.
For example, MS340-HS consists of 4x4 segments, segment dimension is 7680/4 = 1920 pixels of ~44um of each side and
1920*3 = 5760 pixels of size ~14um.
So, precision 0.001um x 5760 = 5.76 um which is about half of this pixel size on full dimension of this segment.
I am pretty sure that the dimensions of the matrix of 5760x5760 "capacitors" should be known with at least pixel size precision.
Another words, to get right answer we need to ask right question.
Mikhail
2022-06-22 11:49 AM
Ross Doyle <ross@rayonix.com>
Dear Chris,
You could use 44.271 um as the best estimate for the unbinned pixel size, and multiples of that for binned pixels. That's somewhat beyond the tolerances of the exact imaging area size (340mm x 340mm), but it's the target expansion number we use in our calculations to make the calibration tables. Also, to answer your question, the corrected pixel space is 340mm x 340mm, pixel edge to pixel edge.
Best regards,
-Ross
From: O'Grady, Paul Christopher <cpo@slac.stanford.edu>
Sent: Wednesday, June 22, 2022 12:01 PM
To: Dubrovin, Mikhail <dubrovin@slac.stanford.edu>
Subject: Fwd: MS340-HS pixel size and "gap" question
Hi Mikhail,
I think the answer below is good enough for our purposes. Do you agree?
Dubrovin, Mikhail
Hi Chris,
Thank you for efforts to shed light on this murky issue.
Yes, I do. Hope this will convince our scientists. And I can use this size for implementation.
To completely convince myself, I would prefer to see a schematic design drawing of a single CCD panel charge moving electrodes of capacitors/pixels ~14um with precise dimensions from edge to edge. Map of squares/rectangles should not be a "proprietary information", right? These dimensions should not depend on electric field shape at the edge and inter-panel gap uncertainties. If Christine confirms that these pixels map has dimensions (340mm/4) 85x85mm with precision of 1 pixel width, I will absolutely be happy.
Also, we did not get answer about panels of MS170-HS. Are they the same as for MS340-HS? It is the same topic question, so you may merge them in one question.
Mikhail
2022-06-22 3:04 PM
Dubrovin, Mikhail
Just in order to stimulate this discussion, I found scientific publication based on data of this detector
http://www.photocrystallography.eu/pubs/2020/Szarejko-J-Synchrotron-Rad-2020-27-405.pdf
where pixel size is used as 44um sharp. So total error in distance measurement is ~0.5%.
Can't comment on how important this error for measurement is....
And I am pretty sure that this is not the only publication.
Mikhail
