From 113ab8398a295f0da5d48d2bca68ef87d63f5d26 Mon Sep 17 00:00:00 2001
From: Alvaro Tolosa Delgado <alvaro.tolosa.delgado@cern.ch>
Date: Sat, 4 May 2024 17:42:18 +0200
Subject: [PATCH] Add data extension class for FCCee Drift Chamber
---
DDRec/include/DDRec/DCH_info.h | 348 +++++++++++++++++++++++++++++++++
1 file changed, 348 insertions(+)
create mode 100644 DDRec/include/DDRec/DCH_info.h
diff --git a/DDRec/include/DDRec/DCH_info.h b/DDRec/include/DDRec/DCH_info.h
new file mode 100644
index 000000000..a44e3da3c
--- /dev/null
+++ b/DDRec/include/DDRec/DCH_info.h
@@ -0,0 +1,348 @@
+#ifndef DCH_INFO_H_INCLUDED
+#define DCH_INFO_H_INCLUDED
+
+#include "TMath.h"
+
+#include "DDRec/DetectorData.h"
+#include <map>
+
+namespace dd4hep { namespace rec {
+
+
+/* Data structure to store DCH geometry parameters
+ *
+ * Global parameters are members of this class
+ *
+ * Parameters of each layer are stored in the helper
+ * class DCH_info_layer.
+ *
+ * The member database is a container which stores one
+ * DCH_info_layer object per layer.
+ *
+ * To use this class, instantiate an object and define the global parameters.
+ * Then call the method BuildLayerDatabase, which calculates
+ * the parameters of each layer based on the global parameters.
+ *
+ * @author A. Tolosa Delgado, CERN
+ * @date April 2024
+ * @version Drift chamber v2
+ *
+ */
+struct DCH_info_struct
+{
+public:
+ // use alias of types to show more clearly what the variable is
+ // if everything is double, the code is not readable
+ /// type for layer number
+ using DCH_layer = int;
+ /// tpye for lengths
+ using DCH_length_t = double;
+ /// tpye for angles
+ using DCH_angle_t = double;
+ /// Half length of the active volume
+ DCH_length_t Lhalf = {0};
+ /// Inner radius of the active volume
+ DCH_length_t rin = {0};
+ /// Outer radius of the active volume
+ DCH_length_t rout = {0};
+
+ /// Inner guard wires radius
+ DCH_length_t guard_inner_r_at_z0 = {0};
+ /// Outer guard wires radius
+ DCH_length_t guard_outer_r_at_zL2 = {0};
+
+ /// number of cells of first layer
+ int ncell0 = {0};
+ /// increment the number of cells for each superlayer as:
+ /// ncells(ilayer) = dch_ncell0 + increment*superlayer(ilayer)
+ /// See DCH_info::Get_nsuperlayer_minus_1(ilayer)
+ int ncell_increment = {0};
+
+ /// cells within the same layer may be grouped into sectors, not in use atm
+ int ncell_per_sector = {0};
+
+ /// input number of layers in each superlayer
+ DCH_layer nlayersPerSuperlayer = {0};
+ /// input number of superlayers
+ /// superlayer is an abstract level of grouping layers used to
+ /// parametrize the increment of cells in each layer
+ DCH_layer nsuperlayers = {0};
+ /// Calculated as dch_nlayersPerSuperlayer * dch_nsuperlayers
+ DCH_layer nlayers = {0};
+
+ /// global twist angle
+ /// alternating layers will change its sign
+ DCH_angle_t twist_angle = {0};
+
+ /// Cell width for the first layer
+ double first_width = {0};
+ /// Cell radius for the first layer
+ DCH_length_t first_sense_r = {0};
+
+ void Set_lhalf(DCH_length_t _dch_Lhalf){Lhalf=_dch_Lhalf;}
+ void Set_rin (DCH_length_t _dch_rin ){rin = _dch_rin; }
+ void Set_rout (DCH_length_t _dch_rout ){rout = _dch_rout;}
+
+ void Set_guard_rin_at_z0 (DCH_length_t _dch_rin_z0_guard ){guard_inner_r_at_z0 = _dch_rin_z0_guard; }
+ void Set_guard_rout_at_zL2(DCH_length_t _dch_rout_zL2_guard){guard_outer_r_at_zL2 = _dch_rout_zL2_guard; }
+
+ void Set_ncell0 (int _ncell0 ){ncell0 = _ncell0; }
+ void Set_ncell_increment (int _ncell_increment ){ncell_increment = _ncell_increment; }
+
+ void Set_nlayersPerSuperlayer(int _nlayersPerSuperlayer){nlayersPerSuperlayer = _nlayersPerSuperlayer;}
+ void Set_nsuperlayers (int _nsuperlayers ){nsuperlayers = _nsuperlayers; }
+
+ void Set_ncell_per_sector(int _ncell_per_sector){ncell_per_sector = _ncell_per_sector;}
+
+ void Set_twist_angle (DCH_length_t _dch_twist_angle ){twist_angle = _dch_twist_angle;}
+
+ void Set_first_width (double _first_width ){first_width = _first_width; }
+ void Set_first_sense_r(double _first_sense_r){first_sense_r = _first_sense_r; }
+
+
+ /// Get number of cells in a given layer
+ /// ncells = number of wires/2
+ int Get_ncells(int ilayer){return database.at(ilayer).nwires/2;}
+
+ /// Get phi width for the twisted tube and the step (phi distance between cells)
+ DCH_angle_t Get_phi_width(int ilayer){return (TMath::TwoPi()/Get_ncells(ilayer))*dd4hep::rad;}
+
+ /// phi positioning, adding offset for odd ilayers
+ /// there is a staggering in phi for alternating layers, 0.25*cell_phi_width*(ilayer%2);
+ DCH_angle_t Get_cell_phi_angle(int ilayer, int nphi){ return (Get_phi_width(ilayer) * (nphi + 0.25*(ilayer%2)));}
+
+ /// calculate superlayer for a given ilayer.
+ /// WARNING: division of integers on purpose!
+ int Get_nsuperlayer_minus_1(int ilayer){ return int((ilayer-1)/nlayersPerSuperlayer);}
+
+ /// Calculate radius at z=L/2 given at z=0
+ DCH_length_t Radius_zLhalf(DCH_length_t r_z0) const {
+ return r_z0/cos(twist_angle/2/dd4hep::rad);
+ }
+
+ /// tan(stereoangle) = R(z=0) / (L/2) * tan( twist_angle/2)
+ DCH_angle_t stereoangle_z0(DCH_length_t r_z0) const {
+ return atan( r_z0/Lhalf*tan(twist_angle/2));
+ }
+
+ /// tan(stereoangle) = R(z=L/2) / (L/2) * sin( twist_angle/2)
+ DCH_angle_t stereoangle_zLhalf(DCH_length_t r_zLhalf) const {
+ return atan( r_zLhalf/Lhalf*sin(twist_angle/2));
+ }
+
+ /// WireLength = 2*dch_Lhalf/cos(atan(Pitch_z0(r_z0)/(2*dch_Lhalf)))/cos(stereoangle_z0(r_z0))
+ DCH_length_t WireLength(int nlayer, DCH_length_t r_z0) const {
+ auto Pitch_z0 = database.at(nlayer).Pitch_z0(r_z0);
+ return 2*Lhalf/cos(atan(Pitch_z0/(2*Lhalf)))/cos(stereoangle_z0(r_z0)) ;
+ };
+
+ /// Internal helper struct for defining the layer layout
+ struct DCH_info_layer
+ {
+ /// layer number
+ DCH_layer layer = {0};
+ /// 2x number of cells in that layer
+ int nwires = {0};
+ /// cell parameter
+ double height_z0 = {0.};
+ /// cell parameter
+ double width_z0 = {0.};
+
+ /// radius (cylindral coord) of sensitive wire
+ DCH_length_t radius_sw_z0 = {0.};
+
+ /// radius (cylindral coord) of 'down' field wires
+ DCH_length_t radius_fdw_z0 = {0.};
+
+ /// radius (cylindral coord) of 'up' field wires
+ DCH_length_t radius_fuw_z0 = {0.};
+
+ /// some quantities are derived from previous-layer ones
+ /// stereo angle is positive for odd layer number
+ bool IsStereoPositive() const {
+ return (1 == layer%2);
+ }
+ /// calculate sign based on IsStereoPositive
+ int StereoSign() const {
+ return (IsStereoPositive()*2 - 1);
+ }
+
+ /// separation between wires (along the circle)
+ DCH_length_t Pitch_z0(DCH_length_t r_z0) const {
+ return TMath::TwoPi()*r_z0/nwires;
+ };
+
+ };
+ /// map to store parameters for each layer
+ std::map<DCH_layer, DCH_info_layer> database;
+ bool IsDatabaseEmpty() const { return database.empty(); }
+
+ inline void BuildLayerDatabase();
+ inline void Show_DCH_info_database(std::ostream& io) const;
+
+
+};
+typedef StructExtension<DCH_info_struct> DCH_info ;
+std::ostream& operator<<( std::ostream& io , const DCH_info& d ){d.Show_DCH_info_database(io); return io;}
+
+inline void DCH_info_struct::BuildLayerDatabase()
+{
+ // do not fill twice the database
+ if( not this->IsDatabaseEmpty() ) return;
+
+ auto ff_check_positive_parameter = [](double p, std::string pname) -> void {
+ if(p<=0)throw std::runtime_error(Form("DCH: %s must be positive",pname.c_str()));
+ return;
+ };
+ ff_check_positive_parameter(this->rin ,"inner radius");
+ ff_check_positive_parameter(this->rout ,"outer radius");
+ ff_check_positive_parameter(this->Lhalf,"half length" );
+
+ ff_check_positive_parameter(this->guard_inner_r_at_z0 ,"inner radius of guard wires" );
+ ff_check_positive_parameter(this->guard_outer_r_at_zL2,"outer radius of guard wires" );
+
+
+ ff_check_positive_parameter(this->ncell0,"ncells in the first layer" );
+ ff_check_positive_parameter(this->ncell_increment,"ncells increment per superlayer" );
+ ff_check_positive_parameter(this->ncell_per_sector,"ncells per sector" );
+
+ // if dch_ncell_per_sector is not divisor of dch_ncell0 and dch_ncell_increment
+ // throw an error
+ if( 0 != (ncell0 % ncell_per_sector) || 0 != (ncell_increment % ncell_per_sector) )
+ throw std::runtime_error("dch_ncell_per_sector is not divisor of dch_ncell0 or dch_ncell_increment");
+
+ ff_check_positive_parameter(this->nsuperlayers,"number of superlayers" );
+ ff_check_positive_parameter(this->nlayersPerSuperlayer,"number of layers per superlayer" );
+
+ /// nlayers = nsuperlayers * nlayersPerSuperlayer
+ /// default: 112 = 14 * 8
+ this->nlayers = this->nsuperlayers * this->nlayersPerSuperlayer;
+
+ ff_check_positive_parameter(this->first_width,"width of first layer cells" );
+ ff_check_positive_parameter(this->first_sense_r,"radius of first layer cells" );
+
+
+ // intialize layer 1 from input parameters
+ {
+ DCH_info_layer layer1_info;
+ layer1_info.layer = 1;
+ layer1_info.nwires = 2*this->ncell0;
+ layer1_info.height_z0 = first_width;
+ layer1_info.radius_sw_z0 = first_sense_r;
+ layer1_info.radius_fdw_z0 = first_sense_r - 0.5*first_width;
+ layer1_info.radius_fuw_z0 = first_sense_r + 0.5*first_width;
+ layer1_info.width_z0 = TMath::TwoPi()*first_sense_r/this->ncell0;
+
+ this->database.emplace(layer1_info.layer, layer1_info);
+ }
+
+ // some parameters of the following layer are calculated based on the previous ones
+ // the rest are left as methods of DCH_info or DCH_info_layer class
+ // loop over all layers, skipping the first one
+ for(int ilayer = 2; ilayer<= this->nlayers; ++ilayer)
+ {
+ // initialize empty object, parameters are set later
+ DCH_info_layer layer_info;
+
+ // the loop counter actually corresponds to the layer number
+ layer_info.layer = ilayer;
+ // nwires is twice the number of cells in this particular layer (ilayer)
+ layer_info.nwires = 2*(this->ncell0 + this->ncell_increment*Get_nsuperlayer_minus_1(ilayer) );
+
+ // the previous layer info is needed to calculate parameters of current layer
+ const auto& previousLayer = this->database.at(ilayer-1);
+
+ //calculate height_z0, radius_sw_z0
+ {
+ double h = previousLayer.height_z0;
+ double ru = previousLayer.radius_fuw_z0;
+ double rd = previousLayer.radius_fdw_z0;
+
+ if(0 == Get_nsuperlayer_minus_1(ilayer))
+ layer_info.height_z0 = h*ru/rd;
+ else
+ layer_info.height_z0 = TMath::TwoPi()*ru/(0.5*layer_info.nwires - TMath::Pi());
+
+ layer_info.radius_sw_z0 = 0.5*layer_info.height_z0 + ru;
+ }
+
+ //calculate radius_fdw_z0, radius_fuw_z0, width_z0
+ layer_info.radius_fdw_z0 = previousLayer.radius_fuw_z0;
+ layer_info.radius_fuw_z0 = previousLayer.radius_fuw_z0 + layer_info.height_z0;
+ layer_info.width_z0 = TMath::TwoPi()*layer_info.radius_sw_z0/(0.5*layer_info.nwires);
+
+ // according to expert prescription, width_z0 == height_z0
+ if(fabs(layer_info.width_z0 - layer_info.height_z0)>1e-4)
+ throw std::runtime_error("fabs(l.width_z0 - l.height_z0)>1e-4");
+
+
+
+ this->database.emplace(ilayer, layer_info);
+ }
+
+ std::cout << "\t+ Total size of DCH database = " << database.size() << std::endl;
+ return;
+}
+
+inline void DCH_info_struct::Show_DCH_info_database(std::ostream & oss) const
+{
+ oss << "\n";
+ oss << "Global parameters of DCH:\n";
+ oss << "\tGas, half length/mm = " << Lhalf/dd4hep::mm << '\n';
+ oss << "\tGas, radius in/mm = " << rin/dd4hep::mm << '\n';
+ oss << "\tGas, radius out/mm = " << rout/dd4hep::mm<< '\n';
+ oss << "\tGuard, radius in(z=0)/mm = " << guard_inner_r_at_z0/dd4hep::mm << '\n';
+ oss << "\tGuard, radius out(z=L/2)/mm = " << guard_outer_r_at_zL2/dd4hep::mm << '\n';
+ oss << "\n";
+ oss << "\tTwist angle (2*alpha) / deg = " << twist_angle/dd4hep::deg << '\n';
+ oss << "\n";
+ oss << "\tN superlayers = " << nsuperlayers << '\n';
+ oss << "\tN layers per superlayer = " << nlayersPerSuperlayer << '\n';
+ oss << "\tN layers = " << nlayers << '\n';
+ oss << "\n";
+ oss << "\tN cells layer1 = " << ncell0 << '\n';
+ oss << "\tN cells increment per superlayer = " << ncell_increment << '\n';
+ oss << "\tN cells per sector = " << ncell_per_sector << '\n';
+ oss << "\n";
+ oss << "Layer parameters of DCH:\n";
+ oss
+ << "\t" << "layer"
+ << "\t" << "nwires"
+ << "\t" << "height_z0/mm"
+ << "\t" << "width_z0/mm"
+ << "\t" << "radius_fdw_z0/mm"
+ << "\t" << "radius_sw_z0/mm"
+ << "\t" << "radius_fuw_z0/mm"
+ << "\t" << "stereoangle_z0/deg"
+ << "\t" << "Pitch_z0/mm"
+ << "\t" << "radius_sw_zLhalf/mm"
+ << "\t" << "WireLength/mm"
+ << "\n" << std::endl;
+
+ if( this->IsDatabaseEmpty() )
+ {
+ oss << "\nDatabase empty\n";
+ return;
+ }
+
+ for(const auto& [nlayer, l] : database )
+ {
+ oss
+ << "\t" << l.layer
+ << "\t" << l.nwires
+ << "\t" << l.height_z0/dd4hep::mm
+ << "\t" << l.width_z0/dd4hep::mm
+ << "\t" << l.radius_fdw_z0/dd4hep::mm
+ << "\t" << l.radius_sw_z0/dd4hep::mm
+ << "\t" << l.radius_fuw_z0/dd4hep::mm
+ << "\t" << l.StereoSign()*this->stereoangle_z0(l.radius_sw_z0)/dd4hep::deg
+ << "\t" << l.Pitch_z0(l.radius_sw_z0)/dd4hep::mm
+ << "\t" << this->Radius_zLhalf(l.radius_sw_z0)/dd4hep::mm
+ << "\t" << this->WireLength(l.layer,l.radius_sw_z0)/dd4hep::mm
+ << "\n" << std::endl;
+ }
+ return;
+}
+}} // end namespace dd4hep::rec::
+
+#endif // DCH_INFO_H_INCLUDED
--
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