Someone asked me a question about polarization yesterday so as I was updating the
calculations for longitudinal coherence for Si 220, I decided to included in the elog.
Please note the P polarization for both 8-ID-E and I monochromators now.
Monochromator type Reflectivity FWHM of reflectivity (microrad) dE/E = FWHM/tg(\thetaB) l_l = \lambda/(dE/E) (microns)
Si (111) 96.4 % 24.8 1.36E-4 0.83
Si (220) 89.7 % 19.4 3.96E-5 4.3
This is a dispersive geometry.
I reported also some calculations from 8-ID-I earlier:
https://8id.xray.aps.anl.gov/elog/8-ID/514
ED
Date: Fri, 28 Jun 2019 00:29:56 +0000
From: Eric Dufresne <[email protected]>
To: "8ID beamline staff -- Jiang, Zhang" <[email protected]>,
"Strzalka, Joseph W." <[email protected]>,
Qingteng Zhang <[email protected]>
Cc: Suresh Narayanan <[email protected]>
Subject: NX question answered!
A student asked me a question about X-ray polarization. Here are details on
the 8-ID-D mono for your reference. Note the longitudinal coherence,
bandwidth and reflectivity. https://8id.xray.aps.anl.gov/elog/8-ID/653
Joe, you did quite well on the 2016 upgrade! More flux through higher
reflectivity, and wider bandpass (x3.4), but you loose on brightness some.
I am happy too with higher longitudinal coherence, and with 2D focusing I
think I am doing better too with flux because there is less strain on my
crystal.
Cheers,
Eric |