[Halld-tagger] crystal alignment offsets from CHESS

[Richard Jones]

Hello Ken, Hovanes, and Paul,

Here are the crystal alignment offsets that we measured at CHESS, as
promised last week. Indeed the SI45-90 crystal does have an extra large
displacement, greater than 5 degrees. For the definition of the parameters
delta_x, delta_y, chi_c please see the description in
http://zeus.phys.uconn.edu/halld/diamonds/Analysis/diamond_orientation.pdf

To have some redundancy, we measured rocking curves for several different
lattice vectors and crystal orientations, typically in sets of four as in
[2,2,0], [2,-2,0] and the same ones flipped over. The scatter between the
different values extracted gives an idea of the measurement error on these
offsets that comes about because only one of the angles (the rocking angle)
is measured accurately. Even so, I think the precision is good enough to be
useful to you during the alignment in Hall D. The accuracy on chi_c is as
good as we would ever need.

Test of crystal_offsets calculator with JD70-2 from chess-2-2015:
 delta_x, delta_y, chi_c = 0.0141806609029 0.0394494147526 -39.5251537839
 delta_x, delta_y, chi_c = 0.0140324890906 0.0397954694915 -40.3935842105
 delta_x, delta_y, chi_c = 0.0141669508808 0.0389581575168 -39.9760285739
 delta_x, delta_y, chi_c = 0.0140407226328 0.0403175183741 -39.9768264904

Test of crystal_offsets calculator with SI45-S90 from chess-2-2015:
 delta_x, delta_y, chi_c = -0.0924466551452 0.00306242515430 -2.51634472622
 delta_x, delta_y, chi_c = -0.0910412330502 0.00211521917459 -1.81879381444
 delta_x, delta_y, chi_c = -0.0909830241798 0.00211516659456 -1.8148436326
 delta_x, delta_y, chi_c = -0.0925062062008 0.00306263596926 -2.51102611896

Test of crystal_offsets calculator with JD70-3 from chess-2-2015:
 delta_x, delta_y, chi_c = 0.0555090394862 -0.00226379379488 -42.0637956704

Test of crystal_offsets calculator with J2a100 from chess-2-2015:
 delta_x, delta_y, chi_c = -0.0106666579759 -0.00238477061173 -3.05559121911
 delta_x, delta_y, chi_c = -0.0096842675041 -0.00187779806434 -2.30527990118
 delta_x, delta_y, chi_c = -0.0096987704053 -0.00187776487824 -2.30404125307
 delta_x, delta_y, chi_c = -0.0106518082074 -0.00238485627804 -3.05380543156

Test of crystal_offsets calculator with J1a50 from chess-2-2015:
 delta_x, delta_y, chi_c = 0.0102805220675 0.00907463781033 34.0539182057
 delta_x, delta_y, chi_c = 0.0096628447327 0.00869250348022 32.9548229958
 delta_x, delta_y, chi_c = 0.0098503843131 0.00848177043195 33.5035486408
 delta_x, delta_y, chi_c = 0.0101004163280 0.00930188425789 33.5036777525

-Richard Jones
-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://mailman.jlab.org/pipermail/halld-tagger/attachments/20150518/131b1963/attachment.html