[Sane-analysis] Packing fractions

[O. A. Rondon]

Hi,

I took a look at Hoyoung's table of final packing fractions, to see
whether some information of interest to experiments using ammonia
targets can be extracted. I've posted a summary of my observations at
the link given below.

The packing fractions for some run periods that used the same material
can be combined, resulting in a set of 8 unique packing fractions. This
combination can be done because the packing fraction is insensitive,
within errors, to the dose deposited by the beam; the insert motion
inside the refrigerator; the effect of anneals; and even the removal and
reinsertion of the insert between two periods of different field
orientation; as is clearly shown by the packing fraction for insert C,
load #3 (rows highlighted in cyan).

Therefore, I propose we use only the unique, combined, packing
fractions listed on the bottom table, to get the dilution factors for
the ranges of runs when the same material was used, even if they were
not consecutive or at different kinematics (the pf is independent of
kinematics). This approach will reduce or systematic errors.
Unique pf's:
https://userweb.jlab.org/~rondon/analysis/asym/df/pfs-final-v2.pdf

It can also be seen that the average (not mean) pf. and average error
are 0.06+/-0.03 (5% relative). Since the pf's are unique to each load,
these individual values cannot be combined to form a mean with reduced
error, although, of course, multiple pf's for the same load can be combined.

 From the SANE experience, it would seem that the numbers above can be
used as the baseline for future experiments using 3 cm long cups.

Hoyoung's table is given as a link in the file posted above, and also at
this url:
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Packing_Fractions_Tables

Cheers,

Oscar