diff --git a/README.md b/README.md
index 1702448f78465a1e48ca432fdc35a76c96e88bb4..ba4f67e32defcc401f1b4089635ac08e936348e6 100644
--- a/README.md
+++ b/README.md
@@ -1,379 +1,4 @@
-Tutorial Part 1
-===============
+EIC Software tutorial
+=====================
- * [Introduction](#introduction)
- * [How to build a detector from scratch](#how-to-build-a-detector-from-scratch)
- + [Compiling a new detector](#compiling-a-new-detector)
- + [Building the geometry](#building-the-geometry)
- - [Compact detector description entry element](#compact-detector-description-entry-element)
- - [Geometry Construction](#geometry-construction)
- * [XML Parsing Tip : Provide good default values](#xml-parsing-tip--provide-good-default-values)
- - [Critical parts of build_detector](#critical-parts-of-build_detector)
- * [The Readout and Bit Fields](#the-readout-and-bit-fields)
- * [Simple Reconstruction Overview of scripts](#simple-reconstruction-overview-of-scripts)
- + [Dependencies](#dependencies)
- + [Running the scripts](#running-the-scripts)
- + [To Do](#to-do)
-
-Introduction
-------------
-
-To a newcomer it might not be immediately clear why a *generic detector
-library* based on `dd4hep` is a good solution to the 'simulation and
-reconstruction geometry problem'. However, with the following examples we
-intend to show how generic detector libraries can be used to access the
-geometry information in simulation and reconstruction.
-
-We try to emphasize in the following examples that dd4hep (plus a data model)
-allows the software components to be only loosely decoupled. This allows for a
-'no framework' framework approach where the emphasis is on the underlying
-algorithms used (or being designed). Furthermore, using ROOT's TDataframe, the
-details of each task are made manifest.
-
-Furthermore, the 'no framework' framework allows for the each step to be
-executed using any tool available, however, the IO and data model should be
-fixed.
-
-
-How to build a detector from scratch
-------------------------------------
-
-Building a new (generic) detector using dd4hep is rather straight forward if we
-make the following assumptions.
-
-1. We will use the built-in sensitive detectors
-2. We will use the built-in data model (hits) associated with these detectors
-
-These items can be customized by using the DD4hep plugin mechanism. This will
-be covered in another tutorial.
-
-### Compiling a new detector
-
-For this tutorial we will build a simplified Roman Pot detector.
-We will discuss the detector built in the source file
-`src/GenericDetectors/src/SimpleRomanPot_geo.cpp`.
-To compile this detector into the GenericDetectors library the detector needs
-to be added to the list of sources in the cmake file
-`src/GenericDetectors/CMakeLists.txt`.
-
-```
-dd4hep_add_plugin(${a_lib_name} SOURCES
- src/BeamPipe_geo.cpp
- ...
- src/SimpleRomanPot_geo.cpp # add this line
- )
-```
-
-### Building the geometry
-
-The work of defining the detector is done in a function (here called
-`build_detector`) that is registered using the DD4hep plugin macro
-`DECLARE_DETELEMENT`.
-
-```
-static Ref_t build_detector(Detector& dtor, xml_h e, SensitiveDetector sens)
-{
- xml_det_t x_det = e;
- Material air = dtor.air();
-...
-}
-DECLARE_DETELEMENT(SimpleRomanPot, build_detector)
-```
-
-The argument signature of the `build_detector` is:
-- `Detector& dtor`: This handle provides the main hook to the detector tree (`dd4hep::Detector`).
-- `xml_h e`: Handle to the XML `<detector>` tag associated with the detector in
- the "compact" detector description file (more on this later). This provides
- the mechanism for feeding in the run-time construction parameters.
-- `SensitiveDetector sens`: The sensitive detector to be assigned to the
- sensitive volumes/elements of the detector.
-
-The DD4hep plugin macro `DECLARE_DETELEMENT(SimpleRomanPot, build_detector)`
-stamps out the necessary boiler plate code to register a new detector called
-`SimpleRomanPot` which is build by calling `build_detector`.
-
-#### Compact detector description entry element
-
-The `<detector>` tag defines a new instance of a detector and requires the
-attributes "id", "name", and "type". For example:
-
-```
-<detector id="1" name="MyRomanPot" type="SimpleRomanPot"
- vis="RedVis" readout="RomanPotHits" zoffset="1.0*m">
-</detector>
-````
-
-This defines an instance of the detector named "MyRomanPot" of type
-"SimpleRomanPot" (i.e. the type-name given in the first argument of the DD4hep
-`DECLARE_DETELEMENT` macro) and with id=1. The additional attributes (vis,
-readout, zoffset) will are optional.
-
-The detector tag is provided as the second argument in the `build_detector`
-function. It can be parsed *how ever you want* in order to extract detector
-information. The allowed attributes are listed in
-[`UnicodeValues.h`](http://test-dd4hep.web.cern.ch/test-dd4hep/doxygen/html/_unicode_values_8h_source.html)
-where it is clear how to add new attributes.
-
-
-#### Geometry Construction
-
-If you are familiar with Geant4 or TGeo geometry construction then this will be
-easy. DD4hep has TGeo under hood but there are a few naming tweaks. The
-following table will help orient the user.
-
-| *DD4hep* | *Geant4* | *TGeo |
-| ------ | -------- | ---- |
-| Solid | G4VSolid | TGeoShape |
-| Volume | G4LogicalVolume | TGeoVolume |
-| PlacedVolume | G4PVPlacement | TGeoNode |
-| Element | G4Element | TGeoElement |
-| Material | G4Material | TGeoMaterial/TGeoMedium|
-
-##### XML Parsing Tip : Provide good default values
-
-If you have a detector parameter which we later will tweak (while optimizing
-the design) try to get the value from the xml element but provide a good
-default value. For example:
-
-```
-double radius = ( x_det.hasAttr(_Unicode(radius)) ) ? x_det.attr<double>(_Unicode(radius)) : 5.0*dd4hep::cm;
-```
-
-This provides a default radius of 5 cm when `x_det` does not have a "radius"
-attribute defined. We will return to this later.
-
-#### Critical parts of build_detector
-
-
-We will now look at parts of the source file `src/GenericDetectors/src/SimpleRomanPot_geo.cpp`.
-
-```
-static Ref_t build_detector(Detector& dtor, xml_h e, SensitiveDetector sens)
-{
- xml_det_t x_det = e;
- Material air = dtor.air();
- Material carbon = dtor.material("CarbonFiber");
- Material silicon = dtor.material("SiliconOxide");
- Material aluminum = dtor.material("Aluminum");
- Material vacuum = dtor.material("Vacuum");
- Material supp_mat = carbon;
- Material sens_mat = silicon;
- int det_id = x_det.id(); // id=1
- string det_name = x_det.nameStr(); // "MyRomanPot"
-```
-
-Here we are grabbing the materials that are assumed to be already defined. Also
-we are getting the detector id and name defined in the `detector` tag.
-
-Next we define an [Assembly
-volume](http://test-dd4hep.web.cern.ch/test-dd4hep/doxygen/html/classdd4hep_1_1_assembly.html).
-Here we also stumble upon the important class
-[`dd4hep::DetElement`](http://test-dd4hep.web.cern.ch/test-dd4hep/doxygen/html/classdd4hep_1_1_det_element.html#details).
-It is a means of providing the detector hierarchy/tree, but doesn't necessarily
-have to map exactly to detector geometry. However, it typically will typically
-parallel the geometry (and probably should).
-
-```
- string module_name = "RomanPot";
- Assembly assembly(det_name + "_assembly");
- DetElement sdet( det_name, det_id);
- sens.setType("tracker");
-```
-The last line sets the `SensitiveDetector sens` argument to be the tracker type
-(which is a DD4hep built-in). We will soon assign this to sensitive volumes.
-`sdet` is associated with the mother detector element by the constructor which
-looks up the detector name (here "MyRomanPot").
-
-```
- double z_offset = (x_det.hasAttr(_Unicode(zoffset))) ? x_det.attr<double>(_Unicode(zoffset)) : 0.0;
- double thickness = (x_det.hasAttr(_Unicode(thickness))) ? x_det.attr<double>(_Unicode(thickness)) : 0.01*dd4hep::cm;
-```
-Here we grab attributes and provide default values. We continue with default
-values that could also be define through attributes, however, we will want to
-add child elements of the detector tag (so the attributes does not grow too
-long).
-
-```
- double rp_chamber_thickness = 5.0*dd4hep::mm;
- double rp_chamber_radius = 5.0*dd4hep::cm;
- double rp_chamber_length = 50.0*dd4hep::cm;
- Tube rp_beam_pipe_tube(rp_chamber_radius, rp_chamber_radius+rp_chamber_thickness, rp_chamber_length/2.0);
- Tube rp_beam_vacuum_tube(0.0, rp_chamber_radius+rp_chamber_thickness, rp_chamber_length/2.0);
- Tube rp_beam_vacuum_tube2(0.0, rp_chamber_radius, rp_chamber_length/2.0);
-
- double rp_detector_tube_radius = 2.5*dd4hep::cm;
- double rp_detector_tube_length = 20.0*dd4hep::cm;
- Tube rp_detector_tube(rp_detector_tube_radius, rp_detector_tube_radius+rp_chamber_thickness, rp_detector_tube_length/2.0);
- Tube rp_detector_vacuum_tube(0.0, rp_detector_tube_radius+rp_chamber_thickness, rp_detector_tube_length/2.0);
- Tube rp_detector_vacuum_tube2(0.0, rp_detector_tube_radius, rp_detector_tube_length/2.0);
-
- ROOT::Math::Rotation3D rot_X( ROOT::Math::RotationX(M_PI/2.0) );
- ROOT::Math::Rotation3D rot_Y( ROOT::Math::RotationY(M_PI/2.0) );
-
- UnionSolid rp_chamber_tee1(rp_beam_vacuum_tube, rp_detector_vacuum_tube, rot_X);
- UnionSolid rp_chamber_tee12(rp_chamber_tee1, rp_detector_vacuum_tube, rot_Y);
-
- UnionSolid rp_chamber_tee2(rp_beam_vacuum_tube2, rp_detector_vacuum_tube2, rot_X);
- UnionSolid rp_chamber_tee22(rp_chamber_tee2, rp_detector_vacuum_tube2, rot_Y);
-
- SubtractionSolid sub1(rp_chamber_tee12,rp_chamber_tee22);
- Volume rp_chamber_vol("rp_chamber_walls_vol", sub1, aluminum);
- Volume rp_vacuum_vol("rp_chamber_vacuum_vol", rp_chamber_tee22, vacuum);
-```
-The above code builds the up the two solids associated with 3 tubes
-intersecting. One volume is the aluminum vacuum chamber walls and the other is
-the vacuum contained within this envelope.
-
-Next we must place these two volumes in the assembly volume (which is just an
-empty container-like volume. The PlacedVolume is then associated with a
-BitFieldValue in the readout's BitField64 readout string. In this case the
-"layer" BitFieldValue. The BitField64 is used to construct unique VolumeIDs and
-CellIDs for PlacedVolumes and Segmentations respectively.
-
-```
- PlacedVolume pv;
- pv = assembly.placeVolume( rp_chamber_vol );
- pv = assembly.placeVolume( rp_vacuum_vol );
- pv.addPhysVolID( "layer", 2 );
-```
-
-Set the PlacedVolume BitFieldValue ID. "2" in this case.
-
-```
- double supp_x_half = 1.0*dd4hep::cm;
- double supp_y_half = 1.0*dd4hep::cm;
- double supp_thickness = 1.0*dd4hep::mm;
- double supp_gap_half_width = 1.0*dd4hep::mm;
- double sens_thickness = 0.1*dd4hep::mm;
-
- Box supp_box( supp_x_half, supp_y_half, supp_thickness/2.0 );
- Box sens_box( supp_x_half-supp_gap_half_width, supp_y_half-supp_gap_half_width, sens_thickness/2.0 );
-
-```
-
-Next we define vectors which are used to define a "surface" (which will later
-generate simulation tracker hits).
-
-```
- // create a measurement plane for the tracking surface attched to the sensitive volume
- Vector3D u( 1. , 0. , 0. ) ;
- Vector3D v( 0. , 1. , 0. ) ;
- Vector3D n( 0. , 0. , 1. ) ;
- //Vector3D o( 0. , 0. , 0. ) ;
-
- // compute the inner and outer thicknesses that need to be assigned to the tracking surface
- // depending on wether the support is above or below the sensor
- // The tracking surface is used in reconstruction. It provides material thickness
- // and radation lengths needed for various algorithms, routines, etc.
- double inner_thickness = supp_thickness/2.0;
- double outer_thickness = supp_thickness/2.0;
- double z_shift = 5.0*dd4hep::mm;
- double xy_shift = 15.0*dd4hep::mm;
-
- SurfaceType type( SurfaceType::Sensitive ) ;
-```
-
-We now define a simple rectangular pixel sensor. This will be the first of
-four: two will come in along the x axis and two along the y axis.
-
-```
- // ------------- x1
- Volume support1_vol( "xsenseor_supp", supp_box, supp_mat );
- Volume sensor1_vol( "xsenseor_sens", sens_box, sens_mat );
- VolPlane surf1( sensor1_vol, type, inner_thickness , outer_thickness, u,v,n);
- sensor1_vol.setSensitiveDetector(sens);
-```
-The code above builds two volumes one which will contain the sensitive volume.
-The sensitive volume is assigned to be a sensitive detector.
-
-```
- DetElement layer1_DE( sdet, "layer1_DE", 1 );
- pv = rp_vacuum_vol.placeVolume( support1_vol, Position(xy_shift,0, -z_shift) );
- pv.addPhysVolID("layer", 1 );
- layer1_DE.setPlacement( pv ) ;
-```
-The above creates a new DetElement, places the support volume in the vacuum,
-sets this PlacedVolume to associate with the layer bitfield, and adds the PV to
-the DetElement. Note the DetElement is constructed with the parent element
-(sdet) being the first argument. In this way it is clear we are building,
-(semi-)parallel to the geometry, a detector element hierarchy.
-
-```
- DetElement mod1( layer1_DE , "module_1", 1 );
- pv = support1_vol.placeVolume(sensor1_vol, Position(0,0,0));
- pv.addPhysVolID("module", 1 );
- mod1.setPlacement( pv );
-```
-This creates the module DetElement and places the sensitive volume in the
-support volume (already placed). It also assocates the pv with the module
-bitfield and then adds the PV to the DetElement.
-
-The above is repeated for the three remaining sensitive elements.
-
-Finally we get the top level volume to place the assemble volume. Note we are
-using the zoffset. This PV is then associated with the top level "system"
-bitfieldvalue.
-
-```
- pv = dtor.pickMotherVolume(sdet).placeVolume(assembly, Position(0,0,z_offset));
- pv.addPhysVolID("system", det_id); // Set the subdetector system ID.
- sdet.setPlacement(pv);
-
- assembly->GetShape()->ComputeBBox() ;
- return sdet;
-}
-
-```
-
-The Readout and Bit Fields
---------------------------
-
-
-Simple Reconstruction Overview of scripts
----------------------------------------
-
-In the examples here we use ROOT and the LCIO data model.
-The following scripts should be executed in order:
-
-1. `run_example` : bash script that runs `ddsim` with the Geant4 macro file
- `gps.mac` and the input geometry defined in `gem_tracker_disc.xml`.
-2. `scripts/example_hit_position.cxx` : ROOT script showing how to use both the
- "segmentation" and "surface" geometry to get the hit position information.
-3. `scripts/example_cell_size.cxx` : ROOT script showing how information about
- the geometry beyond the position.
-4. `scripts/example_digi.cxx` : ROOT script performing a crude digitization of
- gem tracker hits.
-5. `scripts/example_hit_recon.cxx` : ROOT script that shows how to to use
- dd4hep to lookup a 'segment' (cell) position based on the unique cellID
- attached to the hit object.
-6. `scripts/example_tracking.cxx` : ROOT script showing how to use the
- `GenFind` finding library along with `GenFit` to produce tracks.
-
-### Dependencies
-
-There are some library dependencies:
-
-- DD4hep
-- lcgeo
-- GenFind
-- GenFit
-- NPdet
-
-
-### Running the scripts
-
-
-```
-./run_example
-root scripts/example_digi.cxx++
-root scripts/example_hit_position.cxx++ # no output
-root scripts/example_cell_size.cxx++ # no output
-root scripts/example_hit_recon.cxx++
-root scripts/example_tracking.cxx++
-```
-
-### To Do
-
-- Show how to build a detector
-- Finish track fitting script.
-- Create example for basic PFA usage
+https://eicweb.phy.anl.gov/Argonne_EIC/tutorial/tutorial_part1
diff --git a/gem_tracker.xml b/gem_tracker.xml
index cfc4938d9a58c953160aa927729c9c58ea354214..5fd593a13a3d1bb7e3f348a94a2cb1c03cb66238 100644
--- a/gem_tracker.xml
+++ b/gem_tracker.xml
@@ -127,7 +127,7 @@
<layer id="5" z="315 *cm" inner_r="109.0*cm" outer_r="237.0*cm" phi0_offset="-0.5*deg" />
</detector>
-->
- <detector id="2" name="GEMTracker_SIDIS" vis="RedVis" type="GEMTrackerDisc" readout="GEMTrackerHits" >
+ <detector id="2" name="GEMTracker_SIDIS" vis="RedVis" type="GEMTrackerDiscSOLID" readout="GEMTrackerHits" >
<layer id="1" z="-175 *cm" inner_r="36*cm" outer_r="87.0*cm" phi0_offset="0.0*deg" />
<layer id="2" z="-150 *cm" inner_r="21*cm" outer_r="98.0*cm" phi0_offset="0.0*deg" />
<layer id="3" z="-119 *cm" inner_r="25*cm" outer_r="112.0*cm" phi0_offset="0.0*deg" />
@@ -183,7 +183,7 @@
<fields>
<field name="GlobalSolenoid" type="solenoid"
- inner_field="10.0*tesla"
+ inner_field="5.0*tesla"
outer_field="-0.5*tesla"
zmax="4.0*m"
outer_radius="2.0*m">
diff --git a/gps.mac b/gps.mac
index 6f6e0ceb43187c31691637dc05ba580b6c36aa16..34a060adb34323d971800a0fdb6573c1dd113540 100644
--- a/gps.mac
+++ b/gps.mac
@@ -2,11 +2,11 @@
/run/initialize
/gps/verbose 2
-/gps/particle e-
+/gps/particle pi-
/gps/number 1
/gps/ene/type Gauss
-/gps/ene/mono 9.0 GeV
+/gps/ene/mono 3.5 GeV
/gps/ene/sigma 3.0 GeV
/gps/pos/type Volume
@@ -14,9 +14,11 @@
/gps/pos/centre 0.0 0.0 0.0 cm
/gps/pos/radius 0.01 cm
/gps/pos/halfz 0.01 cm
-/gps/position 0 0 -6.0 m
+/gps/position 0 0 0 cm
-/gps/direction 0 0.1 1.0
-#/gps/ang/type iso
+#/gps/direction 0 0.1 1.0
+/gps/ang/type iso
+/gps/ang/mintheta 30 degree
+/gps/ang/maxtheta 160 degree
/run/beamOn 100
diff --git a/scripts/example_cell_size.cxx b/scripts/example_cell_size.cxx
index 2bdc1b2f8a09466a93ab86190b64755a85516a1b..40020a3c3475af7253219bf7bc8f4eb10a285d65 100644
--- a/scripts/example_cell_size.cxx
+++ b/scripts/example_cell_size.cxx
@@ -1,15 +1,7 @@
-//
-//#include <vector>
-//#include <tuple>
-//#include <algorithm>
-//#include <iterator>
-//
-//// DD4hep
-//// -----
-//// In .rootlogon.C
-//// gSystem->Load("libDDDetectors");
-//// gSystem->Load("libDDG4IO");
-//// gInterpreter->AddIncludePath("/opt/software/local/include");
+R__LOAD_LIBRARY(libfmt.so)
+#include "fmt/core.h"
+R__LOAD_LIBRARY(libDDG4IO.so)
+
#include "DD4hep/Detector.h"
#include "DDG4/Geant4Data.h"
#include "DDRec/CellIDPositionConverter.h"
@@ -17,23 +9,10 @@
#include "DDRec/Surface.h"
#include "ROOT/RDataFrame.hxx"
-//#include "lcio2/MCParticleData.h"
-//#include "lcio2/ReconstructedParticleData.h"
-
-//#include "Math/Vector3D.h"
-//#include "Math/Vector4D.h"
-//#include "Math/VectorUtil.h"
#include "TCanvas.h"
-//#include "TLegend.h"
-//#include "TMath.h"
-//#include "TRandom3.h"
-//#include "TFile.h"
-//#include "TH1F.h"
-//#include "TH1D.h"
-//#include "TTree.h"
#include "TChain.h"
-//#include "TF1.h"
-/** Cell size example.
+
+ /** Cell size example.
*
* Makes use of ROOT's TDataframe
* (https://root.cern.ch/doc/master/classROOT_1_1Experimental_1_1TDataFrame.html)
@@ -54,7 +33,7 @@
* This example shows how to get both kinds of hit positions.
*
*/
-void example_cell_size(const char* fname = "test_tracker_disc.root"){
+void example_cell_size(const char* fname = "gem_tracker_sim.root"){
using namespace ROOT::Math;
@@ -65,14 +44,14 @@ void example_cell_size(const char* fname = "test_tracker_disc.root"){
ROOT::RDataFrame d0(*t, {"GEMTrackerHits","MCParticles"});
//How to get the type of the initial branch: (vector<dd4hep::sim::Geant4Tracker::Hit*>)
- //std::cout << t->GetBranch("GEMTrackerHits")->GetClassName() << std::endl;
+ std::cout << t->GetBranch("MCParticles")->GetClassName() << std::endl;
// -------------------------
// Get the DD4hep instance
// Load the compact XML file
// Initialize the position converter tool
dd4hep::Detector& detector = dd4hep::Detector::getInstance();
- detector.fromCompact("gem_tracker_disc.xml");
+ detector.fromCompact("gem_tracker.xml");
dd4hep::rec::CellIDPositionConverter cellid_converter(detector);
// -------------------------
@@ -132,10 +111,12 @@ void example_cell_size(const char* fname = "test_tracker_disc.root"){
dd4hep::rec::ISurface* surf = (si != surfMap->end() ? si->second : nullptr);
dd4hep::rec::Vector3D pos2;
// Get the origin of the surface volume
- if(!surf) pos2 = surf->origin();
std::cout << " Hit Position : " << pos0 << std::endl;
std::cout << "Segmentation-Cell Position : " << pos1 << std::endl;
- std::cout << " Surface Origin Position : " << pos2 << std::endl;
+ if(surf) {
+ pos2 = surf->origin();
+ std::cout << " Surface Origin Position : " << pos2 << std::endl;
+ }
result.push_back( VectorUtil::RotateZ((pos1-pos0), -1.0*pos1.Phi()+TMath::Pi()/2.0).x() );
}
return result;
@@ -155,9 +136,7 @@ void example_cell_size(const char* fname = "test_tracker_disc.root"){
dd4hep::rec::Vector3D pos2;
// Get the origin of the surface volume
if(!surf) pos2 = surf->origin();
- //std::cout << " Hit Position : " << pos0 << std::endl;
- //std::cout << "Segmentation-Cell Position : " << pos1 << std::endl;
- //std::cout << " Surface Origin Position : " << pos2 << std::endl;
+ //rotate to cell coordinates
result.push_back( VectorUtil::RotateZ((pos1-pos0), -1.0*pos1.Phi()+TMath::Pi()/2.0).y() );
}
return result;
@@ -175,22 +154,11 @@ void example_cell_size(const char* fname = "test_tracker_disc.root"){
return false;}, {"GEMTrackerHits"})
.Define("deltax", deltax, {"GEMTrackerHits"})
.Define("deltay", deltay, {"GEMTrackerHits"});
-// .Define("derp",
-// [](const std::vector<dd4hep::sim::Geant4Tracker::Hit*>& hits){
-// std::vector<double> res;
-// std::transform(hits.begin(),
-// hits.end(),
-// std::back_inserter(res),
-// [&](auto h) { return h->position.x()/100.0 - 1.0; } );
-// return res;
-// }, {"GEMTrackerHits"})
-
-
- //auto h0 = d1.Histo1D(TH1D("h0", "nhits; ", 100, -10.0,10.0), "deltay");
+
auto h0 = d1.Histo2D( TH2D("h0", "nhits; ", 100, -2.0, 2.0, 100, -2.0, 2.0), "deltax", "deltay");
TCanvas* c = new TCanvas();
h0->DrawClone("colz");
+ c->SaveAs("scripts/example_cell_size.png");
- //d1.Snapshot("EVENT","derp.root");
}
diff --git a/scripts/example_digi.cxx b/scripts/example_digi.cxx
index d5f8284783000003e6f53a17b30477a8dca5c1bb..4307be34b7bf94975ba0966ef53e84fd031a2e31 100644
--- a/scripts/example_digi.cxx
+++ b/scripts/example_digi.cxx
@@ -96,10 +96,11 @@ void example_digi(const char* fname = "gem_tracker_sim.root"){
.Define("RawTrackerHits", digitize_gem_hits, {"GEMTrackerHits"})
;
- auto h0 = d1.Histo1D(TH1D("h0", "nhits; ", 20, 0,20), "nhits");
+ auto h0 = d1.Histo1D(TH1D("h0", "Number of Hits in GEM Tracker; N hits ", 20, 0,20), "nhits");
TCanvas* c = new TCanvas();
d1.Snapshot("digitized_EVENT","gem_tracker_digi.root");
h0->DrawClone();
+ c->SaveAs("scripts/example_digi.png");
}