#include <acts/blob/sPHENIX/Core/include/Acts/MagneticField/SolenoidBField.hpp>

Inheritance diagram for Acts::SolenoidBField:

Collaboration diagram for Acts::SolenoidBField:

Classes
struct	Cache

struct	Config
	Config struct for the SolenoidBfield. More...

Public Member Functions
	SolenoidBField (Config config)
	the constructor with a shared pointer

Vector2	getField (const Vector2 &position) const
	Retrieve magnetic field value in local (r,z) coordinates.

MagneticFieldProvider::Cache	makeCache (const MagneticFieldContext &mctx) const override


Vector3	getField (const Vector3 &position) const
	Get the B field at a position.

Result< Vector3 >	getField (const Vector3 &position, MagneticFieldProvider::Cache &cache) const override


Result< Vector3 >	getFieldGradient (const Vector3 &position, ActsMatrix< 3, 3 > &derivative, MagneticFieldProvider::Cache &cache) const override

Private Member Functions
Vector2	multiCoilField (const Vector2 &pos, double scale) const

Vector2	singleCoilField (const Vector2 &pos, double scale) const

double	B_r (const Vector2 &pos, double scale) const

double	B_z (const Vector2 &pos, double scale) const

double	k2 (double r, double z) const

Private Attributes
Config	m_cfg

double	m_scale

double	m_dz

double	m_R2

Detailed Description

Implements a multi-coil solenoid magnetic field. On every call, the field is evaluated at that exact position. The field has radially symmetry, the field vectors point in +z direction. The config exposes a target field value in the center. This value is used to empirically determine a scale factor which reproduces this field value in the center.

E_1(k^2) = complete elliptic integral of the 1st kind E_2(k^2) = complete elliptic integral of the 2nd kind

E_1(k^2) and E_2(k^2) are usually indicated as K(k^2) and E(k^2) in literature, respectively _ 2 / pi / 2 2 2 - 1 / 2 E (k ) = | ( 1 - k sin {theta} ) dtheta 1 _/ 0

        _          ____________________

2 / pi / 2| / 2 2 E (k ) = | |/ 1 - k sin {theta} dtheta 2 _/ 0

k^2 = is a function of the point (r, z) and of the radius of the coil R

2 4Rr k = ------------— 2 2 (R + r) + z Using these, you can evaluate the two components B_r and B_z of the magnetic field: _ _ mu I | / 2 \ | 0 kz | |2 - k | 2 2 | B (r, z) = --— ---— | |----—|E (k ) - E (k ) | r 4pi ___ | | 2| 2 1 | | / 3 |_ \2 - 2k / _| |/ Rr

 _                                       _

mu I | / 2 \ | 0 k | | (R + r)k - 2r | 2 2 | B (r,z) = --— -— | | -----------— | E (k ) + E (k ) | z 4pi __ | | 2 | 2 1 | |/Rr |_ \ 2r(1 - k ) / _|

Definition at line 70 of file SolenoidBField.hpp.

View newest version in sPHENIX GitHub at line 70 of file SolenoidBField.hpp

Constructor & Destructor Documentation

Acts::SolenoidBField::SolenoidBField ( Config config )

the constructor with a shared pointer

Note: since it is a shared field, we enforce it to be const

Template Parameters

bField is the shared BField to be stored

Definition at line 22 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 22 of file SolenoidBField.cpp

References Acts::SolenoidBField::Config::bMagCenter, ckf::field, Acts::SolenoidBField::Config::length, m_cfg, m_dz, m_R2, m_scale, multiCoilField(), Acts::SolenoidBField::Config::nCoils, and Acts::SolenoidBField::Config::radius.

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Member Function Documentation

double Acts::SolenoidBField::B_r	(	const Vector2 &	pos,
		double	scale
	)		const

private

Definition at line 84 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 84 of file SolenoidBField.cpp

References k, m_cfg(), physmon_track_finding_ttbar::r, and physmon_track_finding_ttbar::z.

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double Acts::SolenoidBField::B_z	(	const Vector2 &	pos,
		double	scale
	)		const

private

Definition at line 121 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 121 of file SolenoidBField.cpp

References k, m_cfg(), physmon_track_finding_ttbar::r, and physmon_track_finding_ttbar::z.

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Acts::Vector2 Acts::SolenoidBField::getField ( const Vector2 & position ) const

Retrieve magnetic field value in local (r,z) coordinates.

Parameters

[in] position local 2D position

Definition at line 56 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 56 of file SolenoidBField.cpp

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE(), Acts::IntegrationTest::BOOST_DATA_TEST_CASE(), main(), and Acts::solenoidFieldMap().

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Acts::Vector3 Acts::SolenoidBField::getField ( const Vector3 & position ) const

Get the B field at a position.

Parameters

position The position to query at

Definition at line 36 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 36 of file SolenoidBField.cpp

References Acts::VectorHelpers::perp().

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Acts::Result< Acts::Vector3 > Acts::SolenoidBField::getField	(	const Vector3 &	position,
		MagneticFieldProvider::Cache &	cache
	)		const

override

Definition at line 51 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 51 of file SolenoidBField.cpp

Acts::Result< Acts::Vector3 > Acts::SolenoidBField::getFieldGradient	(	const Vector3 &	position,
		ActsMatrix< 3, 3 > &	derivative,
		MagneticFieldProvider::Cache &	cache
	)		const

override

Note: currently the derivative is not calculated

Definition at line 60 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 60 of file SolenoidBField.cpp

double Acts::SolenoidBField::k2	(	double	r,
		double	z
	)		const

private

Definition at line 158 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 158 of file SolenoidBField.cpp

References m_cfg(), physmon_track_finding_ttbar::r, and physmon_track_finding_ttbar::z.

Referenced by pyqqbh(), pysugi(), and rk4step().

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Acts::MagneticFieldProvider::Cache Acts::SolenoidBField::makeCache ( const MagneticFieldContext & mctx ) const

override

Definition at line 31 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 31 of file SolenoidBField.cpp

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE().

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Acts::Vector2 Acts::SolenoidBField::multiCoilField	(	const Vector2 &	pos,
		double	scale
	)		const

private

Definition at line 66 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 66 of file SolenoidBField.cpp

References m_cfg().

Referenced by SolenoidBField().

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Acts::Vector2 Acts::SolenoidBField::singleCoilField	(	const Vector2 &	pos,
		double	scale
	)		const

private

Definition at line 79 of file SolenoidBField.cpp.

View newest version in sPHENIX GitHub at line 79 of file SolenoidBField.cpp

Member Data Documentation

Config Acts::SolenoidBField::m_cfg

private

Definition at line 125 of file SolenoidBField.hpp.

View newest version in sPHENIX GitHub at line 125 of file SolenoidBField.hpp

Referenced by SolenoidBField().

double Acts::SolenoidBField::m_dz

private

Definition at line 127 of file SolenoidBField.hpp.

View newest version in sPHENIX GitHub at line 127 of file SolenoidBField.hpp

Referenced by SolenoidBField().

double Acts::SolenoidBField::m_R2

private

Definition at line 128 of file SolenoidBField.hpp.

View newest version in sPHENIX GitHub at line 128 of file SolenoidBField.hpp

Referenced by SolenoidBField().

double Acts::SolenoidBField::m_scale

private

Definition at line 126 of file SolenoidBField.hpp.

View newest version in sPHENIX GitHub at line 126 of file SolenoidBField.hpp

Referenced by SolenoidBField().

The documentation for this class was generated from the following files:

acts/blob/sPHENIX/Core/include/Acts/MagneticField/SolenoidBField.hpp
acts/blob/sPHENIX/Core/src/MagneticField/SolenoidBField.cpp

Classes

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation