GCOMD2Response::kn_gauss_kernel Class Reference

Inheritance diagram for GCOMD2Response::kn_gauss_kernel:

Public Member Functions
	kn_gauss_kernel (const double &ereco, const double &e0, const double &ec, const double &sigma)
double	eval (const double &e)
	Computes modified Klein-Nishina cross section multiplied with Gaussian kernel.
Public Member Functions inherited from GFunction
	GFunction (void)
	Void constructor.
	GFunction (const GFunction &function)
	Copy constructor.
virtual	~GFunction (void)
	Destructor.
GFunction &	operator= (const GFunction &function)
	Assignment operator.

Protected Attributes
double	m_ereco
double	m_e0
	Incident energy (MeV)
double	m_ec
	Compton edge energy (MeV)
double	m_wgt
	Inverse of Gaussian standard deviation (1/MeV)

Additional Inherited Members
Protected Member Functions inherited from GFunction
void	init_members (void)
	Initialise class members.
void	copy_members (const GFunction &function)
	Copy class members.
void	free_members (void)
	Delete class members.

Detailed Description

Definition at line 94 of file GCOMD2Response.hpp.

Constructor & Destructor Documentation

kn_gauss_kernel()

GCOMD2Response::kn_gauss_kernel::kn_gauss_kernel ( const double & ereco, const double & e0, const double & ec, const double & sigma )

inline

Definition at line 96 of file GCOMD2Response.hpp.

Member Function Documentation

eval()

double GCOMD2Response::kn_gauss_kernel::eval ( const double & e )

virtual

Computes modified Klein-Nishina cross section multiplied with Gaussian kernel.

Parameters

[in]

e

Energy (MeV).

Returns

Modified Klein-Nishina cross section multiplied with Gaussian kernel

Computes the modified Klein-Nishina cross section multiplied with a Gaussian kernel using

$$KN_{\rm mod}(E|E_2,\hat{E_2}) = \sigma_{\rm KN}(E|\hat{E_2}) \times f(E|\hat{E_2}) \times \frac{1}{\sigma^2(E_2) \sqrt{2\pi}} \exp \left( -\frac{1}{2} \frac{(E-E_2)^2}{\sigma^2(E_2)} \right)$$

where

$$\sigma_{\rm KN}(E|\hat{E_2}) = \left( \frac{E/\hat{E_2}}{1-E/\hat{E_2}} \frac{m_e c^2}{\hat{E_2}} \right)^2 - \frac{E}{\hat{E_2}} + \frac{1}{1-E/\hat{E_2}}$$

is the Klein-Nishina cross section, and

$$f(E|\hat{E_2}) = \left \{ \begin{array}{l l} \displaystyle \exp \left( -\mu(E|\hat{E_2}) \, l(\hat{E_2}) \right), & \mbox{if $\hat{E_2} > 12.14$ MeV} \\ \displaystyle 0, & \mbox{otherwise} \\ \end{array} \right .$$

is the probability that a photon, which has been Compton scattered, has no second interaction before escaping (aborption, compton scattering, pair creation), where

$$\mu(E|\hat{E_2}) = 0.72 \, e^{-1.28 (\hat{E_2} - E)^{0.35}} + 0.01 \, (\hat{E_2} - E) + 0.014 \, (\hat{E_2} - E)^{-2.5}$$

is the total linear attenuation coefficient in NaI for all processes, which is an empirical function which describes the values given by Harshaw, and

$$l(\hat{E_2}) = 2.9 \log( \hat{E_2} - 11.14)$$

is an empirical path length in the D2 module (energies are in MeV). $\hat{E_2}$ is the position of the photo peak, $E_2$ is the energy deposit measured in D2, $\sigma(E_2)$ is the standard deviation at the measured energy, and $E$ is the energy over which the convolution is performed.

The code implementation is based on the COMPASS RESRS209 function KLNSUB.F (release 1.0, 14-Oct-91) and CHANCT.F (release 2.0, 26-JAN-93).

Implements GFunction.

Definition at line 1020 of file GCOMD2Response.cpp.

References gammalib::inv_sqrt2pi, m_e0, m_ereco, m_wgt, and gammalib::mec2.

Member Data Documentation

m_e0

double GCOMD2Response::kn_gauss_kernel::m_e0

protected

Incident energy (MeV)

Definition at line 107 of file GCOMD2Response.hpp.

Referenced by eval().

m_ec

double GCOMD2Response::kn_gauss_kernel::m_ec

protected

Compton edge energy (MeV)

Definition at line 108 of file GCOMD2Response.hpp.

m_ereco

double GCOMD2Response::kn_gauss_kernel::m_ereco

protected

Definition at line 106 of file GCOMD2Response.hpp.

Referenced by eval().

m_wgt

double GCOMD2Response::kn_gauss_kernel::m_wgt

protected

Inverse of Gaussian standard deviation (1/MeV)

Definition at line 109 of file GCOMD2Response.hpp.

Referenced by eval().

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

• inst/com/include/GCOMD2Response.hpp
• inst/com/src/GCOMD2Response.cpp