G0 Moller analysis code

PRELIMINARY VERSION 8/21/2002

Location of analysis software

cdaq@cdaqs1:moller/anal/gzero

Contact persons

Taking a Moller run

See: http://hallcweb.jlab.org/document/moller_sbys/moller_sbys.html

Analyzing data

The G0 Moller analysis code that should be used for analyzing the data if delayed helicity reporting is in effect. The G0 part of the code will sort the scaler data according to the true beam helicity (delayed by 2 quartets in the datastream) and feed this in a transparent way to the originial Moller analysis code. It will check that the quartet helicity structure is either +--+ or -++-, and that the reported helicity agrees with the true helicity. It is capable of recognizing missing events in the data stream (see KNOWN BUGS in g0event.F). As in the main G0 analysis code, the true helicity is obtained by running a predictor algorithm for the pseudorandom helicity generator in the polarized source. Calibration constants, beam current limits, etc. are set in 'moller.flags'.
  1. ssh cdaq@cdaqs1. Standard cdaq password.
  2. cd moller/anal/gzero
  3. replay_moller RRRRR, where RRRRR is the run number for Moller data.
See the Hall C Moller How-To
 
http://hallcweb.jlab.org/document/moller_sbys/moller_sbys.html

for more information about analyzing Moller data.

Other executables

replay_moller_orig:

The originial (non-G0) version of the Moller analysis code. It will not modify the data to account for the true G0 helicity.

dumpit:

A utility for looking at a CODA datafile.

Usage: dumpit <codafile>

mockdata:

A utility for generating a mock G0 Moller data file. The data can be made to include skipped events as well as helicity bit errors.

Usage: mockdata

Compiling the code

Currently the code will only compile and execute correctly on Sun (Sun Fortran) machines. This is probably due to the use of non-standard Fortran, which is handled differently by the GNU Fortran and Sun Fortran compilers. If you have the time to fix it, please do! To compile the code make sure that the environment variables
 
CERN_ROOT
CODA_LIB

are set, or go with the defaults, set for cdaqs1. Edit the Makefile if necessary. Typing
 
make

will then build the four executables.