[Primexd] Be empty optimal time

[Ilya Larin]

 Hi Ashot,


following our Thursday's meeting discussion about what should be

the optimal fraction of empty target statistics collection time,

I tried to calculate it assuming that errors are proportional to the square root

of event numbers (which is not exactly true of course).

If I didn't make a mistake somewhere in math - the result

in the attached plot (vertical axis - fraction of time (vs total time) optimal to spent for empty

target measurement for subtraction; horizontal axis - level of background

observed for empty target vs spectrum height observed for target inserted case,

normalized to the same flux).

I got the simple formula for the quantity in the plot: y = 1 - (1-sqrt(x))/(1-x).

If it is true, for our case the optimum for Be is between 25%...30% of total Be time

to spend for Be empty (bckgr level x = 0.1...0.2).


Best regards,

 Ilya.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/primexd/attachments/20190302/5bab4832/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ellin.jpeg
Type: image/jpeg
Size: 68512 bytes
Desc: ellin.jpeg
URL: <https://mailman.jlab.org/pipermail/primexd/attachments/20190302/5bab4832/attachment-0001.jpeg>