During the running phase of the experiment, provide timely analysis to monitor the progress of the experiment and the performance of the equipment. The analysis should be sufficient to permit decisions and changes in direction to be made on the floor, if needed.
Extract GEn/GMn from the asymmetry for the d(e,e'n) reaction. The analysis will also compare asymmetries extracted using charge-specific reactions in the polarimeter, the (n,n) and (n,p) reactions, with the all neutrals (n,N) analysis.
Extract GEp/GMp using the asymmetry for the p(e,e'p) reaction.
Extract GEp/GMp using the asymmetry for the two-step process p(e,e'p) followed by Pb(p,n).
Determine the efficiency and analyzing power of the neutron polarimeter.
Determine the efficiency and analyzing power of the proton polarimeter.
Compare kinematic distributions with simulations and evaluate systematic uncertainties.
One standard version of the analysis codes: standard versions of the analysis codes shall be maintained by A. Semenov. Personal versions are the responsibility of their creators.
Disk space: Whenever the free disk space on the work disk falls below 5 GB (10% of the 50 GB disk), Semenov will delete the oldest files with one-day prior notification.
Transfer to tape: No one should replay more than five (5) runs before moving large data files to tape. If necessary, one may move runs to a personal mss directory before completion of the evaluation process, but files moved to the collaboration tape directory must be checked carefully first.
Identify suitable runs for a given time period.
Examine the tdcL vs. tdcR correlations for the normal run and compare with the sample found in time_calibration.htm. Report significant changes to the run coordinator so that corrective action may be taken, if needed.
Perform the time calibration according to the procedures outlined in time_calibration.htm.
Check time_xxxxx.log for error messages. If a first-pass data file is not read correctly, one should either repeat that replay or select a different run.
Check time_xxxxx.sum for warning messages that indicate problems in the calibration procedure and verify that the numbers of events for each run are consistent with run summary information.
Compare calibration parameters in time_xxxxx.dat with other recent calibrations and make note of any significant changes.
Run the check_calibration kumac using paw and compare the plots in time_xxxxx.ps with the sample file. Evaluate the quality of the calibration, make note of any significant problems or changes, and decide whether the calibration is acceptable for use in second-pass replay.
Perform second-pass replay for the normal run used for time calibration according the procedures outlined in npol_calculations.htm.
Check polxxxxx.log for error messages. If there are inconsistent hit patterns, one should either repeat the first-pass replay or select a different run.
Run the check_detectors program to produce an hbook file. Then run the check_detectors kumac using paw to produce a postscript file. Examine check_xxxxx.ps carefully, comparing with the sample provided. Evaluate the performance of each detector and make note of any significant problems or changes.
Run the make_histograms script to produce an hbook file containing histograms of physics variables. Then run the basic_histograms kumac using paw to produce a postscript file. Examine histo_xxxxx.ps carefully, comparing with the sample provided and making note of any significant problems or changes. Make sure that the kinematic distributions are sensible.
If these procedures are successful and the results acceptable, report the calibration to genlog. Your report should include:
runs employed and statistics found
description of results, including any marginal aspects (e.g., outer rear taggers) and any significant changes relative to other recent calibrations
new or changing features or problems
expected range of runs for which this calibration should be useful
Select suitable runs: for each cycle, choose at least one run of each distinct type (cosmic, LD2 with Charybdis in 0/+/- states, LH2 with Charybdis in 0/+/- states, dummy if available, etc.) During the running phase we need to be selective, but later all good runs will be replayed. The following steps must be performed for each run selected, taking care to follow the guidelines on use of disk space.
First-pass replay: run engine and compare the number of events with run sheets.
Second-pass replay:
Run the do_npol_calculations script and compare the number of events with the report from engine. Check that no hbook errors or inconsistent hit patterns are reported in polxxxxx.log.
Produce check_detectors.ps and evaluate the performance of each detector, noting any significant problems or changes.
Report replay results to the appropriate bookkeeper. The report should include:
run number, target, Charybdis current, average beam current, number of events
calibration file and runs employed by calibration
qualitative evaluation
description of detector problems
files transferred to tape
Combine files into archive files using the following commands:
tar -cvf paw_xxxxx.tar polxxxxx_*.paw
tar -cvf rzdatxxxxx.tar polrawxxxxx_*.rzdat
Use jput to copy files to mss. You will receive a mail message with information about the storage result for each file attempted. Unfortunately, because the jput command is unreliable, it is necessary to check its results carefully. Obviously, if the mail message reports "failed", you must try again. However, even if the message reports "done", you still must compare the file size on tape with the file size on disk. This information may be found either on line 11 of the text file in the mss directory or by using the script /work/hallc/e93038/jones/scripts/check_mss.tcl.
If the file sizes are inconsistent or another problem is found with a file on tape, send a request to the Computer Center to delete the file from mss. After receiving confirmation, repeat the transfer and checking procedure.
Analysis results (hbook and postscript files, summary tables, etc.) should be placed in the group directory
/group/e93038/results
Previous versions should be renamed by appending where a suffix based upon the creation date for the old file using the format YYMMDD where YY is a 2-digit date, MM is a 2-digit month, and DD is a 2-digit day. For example, a file created on March 15, 2001 would be renamed as follows:
mv filename filename.010315
All files must be saved in write-protected mode using
chmod ugo=r filename
After completion, make a genlog entry and send an e-mail message to madey@jlab.org with a copy to semenov@jlab.org.
Create a database for all good runs that will be used in the production phase of analysis. The database shall include the main run parameters, polarization information, detector problems, beam problems (e.g., charge asymmetry, position or current fluctuations, etc.)
Finalize the HMS calibration parameters. Do we need new optics matrix elements?
Assess pulse-height calibrations and make corrections for the dependence of pulse height upon singles rates.
Perform NPOL timing calibrations.
Upgrade the second-pass replay to handle protons correctly. The present version was designed primarily for neutrons and does not compensate for energy loss in lead or plastic and does not identify the NPOL scattering vertex for protons properly. Furthermore, the charge selection algorithm is presently designed for rejection rather than selection of charged tracks.
Replay runs.
Extract asymmetries.
Upgrade simulation to include energy loss and multiple scattering for protons.
Compare kinematic distributions with simulation, determine acceptances, and dependence of asymmetry upon acceptance averaging.
Estimate backgrounds:
randoms
pion production
charge exchange
Evaluate systematic uncertainties
precession angle
false asymmetry
track reconstruction and charge misidentification
threshold variations
Evaluate NPOL efficiency and analyze power.
Extract GEp/GMp.
Extract GEn/GMn.
The following links provide access to documentation and programs used for the analysis of E93-038 data. Both the programs and documentation are under continual development and are changing rapidly.
The installation procedures were streamlined in Version 2.3. The entire package of programs and sample scripts, inputs, and kumacs is contained in the self-extracting archive file GEN_analyzer.uu. The procedure for a new installation is:
Create the top directory for your copy of the software. Download GEN_analyzer.uu and give it executable status using chmod 744 GEN_analyzer.uu. Then unpack the archive by typing GEN_analyzer.uu.
The script init_make establishes environment variables and creates subdirectories in which libraries and executable images for the Linux and Sun platforms will be written. This script was written for JLab and may need to be modified for your computing environment. Once those modifications are made, use source init_make.
The source files for each library and program are found in separate subdirectories. Each of these subdirectories contains a Makefile intended to be used with the gmake utility. The present makefiles will work on either Linux or Sun platforms at JLab, but for other institutions or other platforms you will need to modify the environment variables in the first few lines of each makefile so that they point to the appropriate local compilers and libraries and include the proper options for those choices. The environment variable OSNAME identifies the current operating system and should be aliased to the variable used by your system for this purpose. CERN_ROOT points to the top directory containing CERN libraries.
The script make_all compiles and links all programs in the distribution package. You can also build each component separately, but if you are working at a facility with several incompatible operating systems, such as JLab, you should first use gmake clean to remove any old object files that might have been created with another system. Issuing the gmake command should then build the component within the present directory.
The present makefiles use the g77 compiler for Linux. Many warning messages about type inconsistencies in the cernlib subroutines will appear but are harmless.
The scripts for running these programs have also been streamlined in Version 2.3. The Samples subdirectory contains scripts and input files for each kinematical condition. These files should be copied to your working directory and modified as needed. The most important modifications will be to setup_analyzer, which establishes environment variables that point to the appropriate versions of each program, the locations for raw data and for output files, and to the input files that supply parameters and cuts. This file will need to be adjusted for your environment. The command source setup_analyzer should then be used before working with any of these programs or when changing from one kinematical condition to another. The script will inquire for the kinematical condition and will report the files that it will use. Check these carefully before proceeding.
Maintained by: James J. Kelly
Last revised: June 7, 2001