[Solid_ec] SoLID EC meeting at 10am Tuesday

[Xiaochao Zheng]

Dear All:

Minutes for yesterday's meeting have been posted at:

http://hallaweb.jlab.org/experiment/PVDIS/SoLID/EC/meetings/SoLID_EC_Weekly_minutes.html#20130430

The two main conclusions are as follows:

*** Main conclusion 1: Using 6+1 cluster sum alone isn't enough. One must store all waveforms on tape. Waveform analysis off-line will potentially improve PID by a factor of 10 (estimated using 4ns vs. 50ns timing);
*** Main conclusion 2: We must have a sophisticated pion trigger and pion sample analysis. If the contamination is 5%, then we must measure pion asymmetry to 1% level in order to control the systematic uncertainty to below 0.05% (1/10 of the statistical error). This means pion samples can be as high as 1/4 of the electron samples. Perhaps we should aim for equal amount of pion and electron events, for offline analysis.

The to-do list is copied below:

A) Zhiwen will continue optimizing the baffles, focusing on reducing the photons. However, must pay attention to not reduce e- rates;
B) Jin will do simple simulation of how 10%, 15%, 30%, and 50% light loss will affect Preshower PID. These % are chosen to reflect the light loss of Kuraray at 100krad, S.G. at 100krad, Kuraray at 700krad and S.G. at 700krad.
C) Jin will continue to trigger simulation, now including all backgrounds.
D) Alexandre will work on DAQ, to accomodate the recording of all waveforms. This will likely double the DAQ cost and add $1M.
E) Jin will work with Alexandre on designing the pion triggers. Similar PID analysis/simulation as for electrons must be done for pions as well. (For example, a large electron contamination in pion triggers will significantly increase the error on the measured pion asymmetry).
F) Jin will think about additional EC methods to improve PID.
G) Xiaochao received pi/e ratio table and CC performance table from M.P., will try to work on the files. Also will need to make sure CC simulations include backgrounds as well.

Thanks,

Xiaochao