On 3 Nov 2015, at 10:18, Jonathan Davies <[log in to unmask]> wrote:Thanks Jacob
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Subject: RE: [ccp4bb] New Rule for PADs Date: Tue, 3 Nov 2015 01:05:19 +0000 From: Keller, Jacob <[log in to unmask]> To: Jonathan Davies <[log in to unmask]> >Has there been any further discussion on this?
Only a resounding silence…!
>I don't fully understand why one would require such a high multiplicity, would there be any significant difference between a dataset with a multiplicity of 100 compared to one with a multiplicity of 20 say, or even 10 (apart from specific cases such as sulphur SAD)?I was thinking that for estimations of errors, which can be important, this would be very good.
>Would the attenuation also possibly affect the resolution, i.e. worse signal to noise in high resolution shell?
No, not at all, and this is exactly my point. With PADs, there is zero readout noise, so it does not matter whether you collect your photons in 10 frames or 1000 frames: the signal is the same. The benefit is huge, however, in that reciprocal space is sampled evenly as a function of radiation dose, whereas in the usual method, crystals are damaged by the time the dataset reaches full completeness.
Thanks for your interest—you could post this to the list, and it might engender some interesting discussion.
Jacob
On 26/10/15 19:35, Keller, Jacob wrote:[log in to unmask]" type="cite" class="">How about a new rule for data collected on pixel area detectors (Pilatus etc): Attenuate to ensure multiplicity/redundancy greater than 100? JPK ******************************************* Jacob Pearson Keller, PhD Looger Lab/HHMI Janelia Research Campus 19700 Helix Dr, Ashburn, VA 20147 email: [log in to unmask] *******************************************