ROOT Analyzer/Running

As of the tag "HitMaps" in the master branch, the Hall C++ analyzer will read Hall C style CTP parameter files, and read a Hall C data file and sort HMS hodoscope data and HMS drift chamber data into Hall C style hit lists. It will also fill global variables from which hodoscope hit maps can be created.

Updating software

If you don't already have a copy of the Hall C Analyzer git repository, go to Analyzer/Git to set it up.

To make sure your git repository is up to date, do

 git pull

in both the top hcana directory and the "podd" sub directory and make sure you are on the "develop" branch for the hcana code and the "master" branch in the podd directory. The hcana code should be at tag "HitMaps" or later and the podd tag snould be "1.5.22_HC02" or later.

Decoding hodoscope and drift chamber hits

To demonstrate the analyzer decoding hits, retrieve the file hcana_testing_work.tar.gz. Unpack it into your hcana directory which will make a subdirectory "work". After making sure the analyzer is cleanly compiled, from "work" do:

 ../hcana
 .x hodtest.C

hodtest.C is a script that sets up an analysis. Look in podd/examples for Hall A analyzer script examples.

To see hits printed out by the analyzer, edit hodtest.C and comment out the line

 HMS->AddDetector( new THcDriftChamber("dc", "Drift Chambers" ));

before running the script. To see hodoscope hits, uncomment some code at the end of the THcHodoscope::Decode method.

Running this script will create a root file, "hodtest.root." The contents of this file are controled by "output.def". (See hcana/podd/examples/output_example.def for examples of how to make an output definition file.)

To see the histograms that were created, do:

 ../hcana
 .x hitmaps.C

which should make this plot:

The analyzer does nothing Hall C specific beyond printing hits and filling the hitmap histograms. But it does serve as an example of how to decode hits for other detectors and as a starting point for writing detector analysis code.

Parameters

To try just reading parameters, run the analyzer from the top directory.

 ./hcana

Once it starts up, type

 gHcParms->Load("hctest.input")

To dump the parameters read

 gHcParms->PrintFull()

Some examples of accessing individual variables

 analyzer [3]  Double_t ProtonMass = *(Double_t *)gHcParms->Find("proton")->GetValuePointer();
 analyzer [4] ProtonMass
 (Double_t)9.38272000000000048e+02

 analyzer [5] Int_t *integerarray = (Int_t *)gHcParms->Find("integerarray")->GetValuePointer();
 analyzer [6] integerarray[3]
 (Int_t)4