The Bfieldcomponentklm1 class. More...

#include <BFieldComponentKlm1.h>

Inheritance diagram for BFieldComponentKlm1:

Collaboration diagram for BFieldComponentKlm1:

[legend]

Classes
struct	BFieldPoint
	Trivial struct representing rz coordinate. More...

Public Member Functions
	BFieldComponentKlm1 ()=default
	The BFieldComponentklm1 constructor.

virtual	~BFieldComponentKlm1 ()=default
	The BFieldComponentklm1 destructor.

virtual void	initialize () override
	Initializes the magnetic field Component. More...

virtual B2Vector3D	calculate (const B2Vector3D &point) const override
	Calculates the magnetic field vector at the specified space point. More...

virtual void	terminate () override
	Terminates the magnetic field Component.

void	setMapFilename (const std::string &filename)
	Sets the filename of the magnetic field map. More...

void	setNLayers (int b, int e)
	Sets the number of barrel and endcap layers. More...

void	setBarrelRegion (double minR, double maxZ, double offset)
	Sets the dimensions of the barrel region. More...

void	setEndcapRegion (double minR, double minZ)
	Set the dimensions of the endcap region. More...

void	setLayerParam (double bgapl0, double bironth, double egap, double dl)
	Set the layer parameters @bgapl0 barrel gap height for layer 0 @bironth barrel iron thickness @egap endcap gap height @dl distance between two layers.

Private Attributes
double	m_cospi8 {cos(M_PI / 8)}
	cos(pi/8)

double	m_cos3pi8 {cos(3 * M_PI / 8)}
	cos(3pi/8)

double	m_cospi4 {cos(M_PI / 4)}
	cos(pi/4)

std::string	m_mapFilename {""}
	The filename of the magnetic field map.

double	m_mapOffset {0}
	Offset required because the accelerator group defines the Belle center as zero.

double	m_barrelRMin {0}
	The minimum boundaries of BKLM region in r.

double	m_barrelZMax {0}
	The maximum boundaries of BKLM region in r.

double	m_endcapRMin {0}
	The minimum boundaries of EKLM region in r.

double	m_endcapZMin {0}
	The minimum boundaries of EKLM region in z.

int	m_nBarrelLayers {0}
	The number of layers per 1 sector for BKLM.

int	m_nEndcapLayers {0}
	The number of layers per 1 sector for EKLM.

double	m_barrelGapHeightLayer0 {0}
	Gap height of BKLM layer0.

double	m_endcapGapHeight {0}
	Gap height of BKLM layer1-14.

double	m_dLayer {0}
	deppth of BKLM module?

double	m_barrelIronThickness {0}
	Thickness of Barrel iron plate.

double	m_barrelZBreakpoint [15] {0}
	z position of breakpoints between the two linear approximations of Bz in the barrel. More...

double	m_barrelRBreakpoint [15] {0}
	z position of breakpoints between the two linear approximations of Br in the barrel. More...

double	m_barrelFieldZSlope1 [15] {0}
	Slope of Bz before the breakpoint in the barrel. More...

double	m_barrelFieldZIntercept1 [15] {0}
	Intercept of Bz before the beackpoint in the barrel. More...

double	m_barrelFieldZSlope2 [15] {0}
	Slope of Bz after the breakpoint in the barrel. More...

double	m_barrelFieldZIntercept2 [15] {0}
	Intercept of Bz after the beackpoint in the barrel. More...

double	m_barrelFieldRSlope1 [15] {0}
	Slope of Br before the breakpoint in the barrel. More...

double	m_barrelFieldRIntercept1 [15] {0}
	Intercept of Br before the beackpoint in the barrel. More...

double	m_barrelFieldRSlope2 [15] {0}
	Slope of Br after the breakpoint in the barrel. More...

double	m_barrelFieldRIntercept2 [15] {0}
	Intercept of Br after the beackpoint in the barrel. More...

double	m_endcapZBreakpoint [2][15][5] {{{0}}}
	z position of breakpoints between linear functions in the endcap. More...

double	m_endcapRBreakpoint [2][15][5] {{{0}}}
	r position of breakpoints between linear functions in the endcap First index indicates whether or not where in a gap (0) or in iron (1), second index is the layer and third index is the number of breaks we have in the linear approximation and their positions

double	m_endcapFieldZSlope [2][15][5] {{{0}}}
	Slopes of the linear approximation of Bz in the endcap. More...

double	m_endcapFieldZIntercept [2][15][5] {{{0}}}
	Intercepts of the linear approximation of Bz in the endcap. More...

double	m_endcapFieldRSlope [2][15][5] {{{0}}}
	Slopes of the linear approximation of Br in the endcap. More...

double	m_endcapFieldRIntercept [2][15][5] {{{0}}}
	Intercepts of the linear approximation of Br in the endcap. More...

Detailed Description

The Bfieldcomponentklm1 class.

This class represents a magnetic field map in KLM region and outside of solenoid. This magnetic field is for Belle. This is porting class from g4superb to basf2. The magnetic field map is stored as linear functions in cylindrical coordinates. It is defined by a maximum radius, a minimum z, r and z, the number of layers for Barrel KLM and Endcap KLM. The ZOffset is used to account for the fact that the acceleration group defines 0 to be in the center of the detector, while the detector group defines the IP to be the center.

Definition at line 33 of file BFieldComponentKlm1.h.

Member Function Documentation

◆ calculate()

B2Vector3D calculate ( const B2Vector3D & point ) const

overridevirtual

Calculates the magnetic field vector at the specified space point.

Parameters

point The space point in Cartesian coordinates (x,y,z) in [cm] at which the magnetic field vector should be calculated.

Returns: The magnetic field vector at the given space point in [T]. Returns a zero vector TVector(0,0,0) if the space point lies outside the region described by the Component.

Implements BFieldComponentAbs.

Definition at line 87 of file BFieldComponentKlm1.cc.

 {
   //Get the r and z Component
   double r = point.Perp();
   double x = point.X();
   double y = point.Y();
   double z = point.Z() - m_mapOffset;
   double absZ =  std::abs(z);
  
   B2Vector3D bField(0., 0., 0.);
  
   // Barrel
   if (absZ < m_barrelZMax) {
  
     // This code assumes that we are in the barrel KLM.  Use the field map
     // inside an iron plate; use zero in the gap between the iron plates.
  
     double cosphi = std::abs(x) / r;
     double d = ((cosphi < m_cospi8) ? ((cosphi < m_cos3pi8) ? std::abs(y)
                                        : (std::abs(x) + std::abs(y)) * m_cospi4)
                 : std::abs(x)) - m_barrelRMin - m_barrelGapHeightLayer0;
  
     if (d >= 0.0) {
       int layer = static_cast<int>(floor(d / m_dLayer));
  
       // make sure layer is in a valid range
       if (layer < 0 || layer > m_nBarrelLayers) return bField;
       if (layer == m_nBarrelLayers) {
         layer = m_nBarrelLayers - 1;
         d = layer * m_dLayer; // for extra-thick outermost iron plate
       }
       if ((d - layer * m_dLayer) < m_barrelIronThickness) {
         double br = ((absZ > m_barrelRBreakpoint[layer]) ?
                      m_barrelFieldRIntercept2[layer] + m_barrelFieldRSlope2[layer] * absZ :
                      m_barrelFieldRIntercept1[layer] + m_barrelFieldRSlope1[layer] * absZ);
         if (z < 0.0) { br = -br; }
         bField.SetXYZ(br * x / r, br * y / r,
                       ((absZ > m_barrelZBreakpoint[layer]) ?
                        m_barrelFieldZIntercept2[layer] + m_barrelFieldZSlope2[layer] * absZ :
                        m_barrelFieldZIntercept1[layer] + m_barrelFieldZSlope1[layer] * absZ));
       }
     }
   } else if (absZ > m_endcapZMin) {
     //Endcap
     if (r <= m_endcapRMin) return bField;
  
     // This code assumes that we are in the endcap KLM.
     // The field in an inter-plate gap in the endcap is not zero.
  
     double dz = absZ - (m_endcapZMin - m_endcapGapHeight);
     int layer = static_cast<int>(floor(dz / m_dLayer));
     // make sure layer is in a valid range
     if (layer < 0 || layer >= m_nEndcapLayers) return bField;
  
     int GapIron = 0;      // in gap
     if ((dz - m_dLayer * layer) > m_endcapGapHeight) GapIron = 1;      // in Iron plate?
     for (int j = 0; j < 5; j++) {
       if (r < m_endcapRBreakpoint[GapIron][layer][j]) {
         double br = m_endcapFieldRIntercept[GapIron][layer][j] + m_endcapFieldRSlope[GapIron][layer][j] * r;
         if (z < 0.0) { br = -br; }
         bField.SetX(br * x / r);
         bField.SetY(br * y / r);
         break;
       }
     }
     for (int j = 0; j < 5; j++) {
       if (r < m_endcapZBreakpoint[GapIron][layer][j]) {
         bField.SetZ(m_endcapFieldZIntercept[GapIron][layer][j] + m_endcapFieldZSlope[GapIron][layer][j] * r);
         break;
       }
     }
   }
  
   return bField;
 }

◆ initialize()

void initialize ( void )

overridevirtual

Initializes the magnetic field Component.

This method opens the magnetic field map file.

Reimplemented from BFieldComponentAbs.

Definition at line 23 of file BFieldComponentKlm1.cc.

◆ setBarrelRegion()

void setBarrelRegion	(	double	minR,
		double	maxZ,
		double	offset
	)

inline

Sets the dimensions of the barrel region.

Parameters

minR	minimal radius
maxZ	max extension in z in both directions
offset	map offset in z

Definition at line 87 of file BFieldComponentKlm1.h.

87 { m_barrelRMin = minR; m_barrelZMax = maxZ; m_mapOffset = offset; }

◆ setEndcapRegion()

void setEndcapRegion	(	double	minR,
		double	minZ
	)

inline

Set the dimensions of the endcap region.

Parameters

minR	minimal radius
minZ	starting z coordinate in both directions

Definition at line 93 of file BFieldComponentKlm1.h.

◆ setMapFilename()

void setMapFilename ( const std::string & filename )

inline

Sets the filename of the magnetic field map.

Parameters

filename The filname of the magnetic field map.

Definition at line 74 of file BFieldComponentKlm1.h.

◆ setNLayers()

void setNLayers	(	int	b,
		int	e
	)

inline

Sets the number of barrel and endcap layers.

Parameters

b	barrel layers
e	endcap layers

Definition at line 80 of file BFieldComponentKlm1.h.

Member Data Documentation