6. Geometry commands

Macro commands related to geometry of the target.

Target geometry is located inside a World, and consists of a Bulk and arbitrary number of Back End Of Line (BEOL) layer volumes (optional). Inside the Bulk volume, one Sensitive Volume (SV) is defined with same material as the Bulk. The scoring of defined quantities (\(E_{dep}\), \(E_{kin}\)) happens only inside this SV.

Center of the top Bulk surface is always in the origin (0,0,0). Position of SV (the center of its top surface) is defined relative to this, inside Bulk only.

X-Z side view of a multi-layer target geometry

X-Y top view of a multi-layer target geometry

See examples/SRAM_example.mac.

6.1. Definition of BULK

Use this command only once.

# BULK                MATERIAL      WIDTH unit      THICK unit  BIAS
/SEE/geometry/Bulk    G4_Si         10. um          10. um      true

Bulk parameters	Type	M?	Description	Example value
MATERIAL	string	y	Bulk layer material	G4_Si
WIDTH with unit	double u	y	Bulk width (X and Y dimension)	10 um
THICKNESS with unit	double u	y	Bulk thickness (Z dimension)	9 um
BIAS	bool	y	Enable XS bias in Bulk layer	true

Any predefined G4 element/material from this list can be used for the MATERIAL parameter. Additionally, VACUUM can be also used as predefined material.

Bulk dimensions (RPP): \(w_{b}\) \(\times\) \(w_{b}\) \(\times\) \(t_{b}\)

There are no default values for the parameters of this command.

6.2. Definition of SV

Use this command only once.

# SV                  POSITION unit       X-Y WIDTH unit  THICK unit  BIAS
/SEE/geometry/SV      0. 0. -1. um        3. 1. um        3. um       true

SV parameters	Type	M?	Description	Example value
X, Y, Z POSITION with unit	double[3] u	y	Sensitive Vol. X, Y, Z position	0 0 -1.5 um
X, Y WIDTH with unit	double[1,2] u	y	Sensitive Vol. X, Y dim.	2 1 um
THICKNESS with unit	double u	y	Sensitive Vol. thickness (Z dim.)	1 um
BIAS	bool	y	Enable XS bias in Sensitive Vol.	true

Material of the SV is the same as its mother volume, which by default is the Bulk.

SV dimensions (RPP): \(w^x_{sv}\) \(\times\) \(w^y_{sv}\) \(\times\) \(t_{sv}\)

There are no default values for the parameters of this command.

6.3. Definition of BEOL layers

Optional command, define as many Back End Of Line (BEOL) layers on top of the Bulk volume as one needs. Each BEOL layer is added on top of the previous BEOL layers in the same order as the /SEE/geometry/BEOL/addLayer commands follow each other in the macro.

# BEOL                        MATERIAL    WIDTH unit  THICK unit  BIAS    NAME
/SEE/geometry/BEOL/addLayer   BEOLmix     4. um       800 nm      false   BEOL1
/SEE/geometry/BEOL/addLayer   G4_Ti       4. um       200 nm      false   BEOL2
/SEE/geometry/BEOL/addLayer   OxideMat    4. um       400 nm      false   BEOL3

BEOL layers in a target geometry

addLayer parameters	Type	M?	Description	Example value
MATERIAL	string	y	BEOL layer material	G4_Al
WIDTH with unit	double[1,2] u	y	BEOL layer width (X and Y dim.)	2 1 um
THICKNESS with unit	double u	y	BEOL layer thickness (Z dim.)	1 um
BIAS	bool	y	Enable XS bias in BEOL layer	true
NAME	string	y	Name of BEOL layer	Oxide

Any predefined G4 element/material from this list can be used for the MATERIAL parameter. Additionally, ‘VACUUM’ can be also used as material.

BEOL dimensions (RPP): \(w_{beol1}\) \(\times\) \(w_{beol1}\) \(\times\) \(t_{beol1}\)

There are no default values for the parameters of this command.

6.4. Special geometry commands

Macro command	Type	M?	Description	Example value	Default value
/SEE/geometry/setCylindricalGeometry	bool	n	Use cylindrical volumes instead of default cuboids	true	false
/SEE/geometry/setWorldAsMotherOfSV	bool	n	Use World volume as mother of SV, instead of Bulk volume	true	false

Setting the WorldAsMotherOfSV true makes possible to score outside Bulk. Use with caution! In this case, SV material is VACUUM and SV should be placed outside Bulk volume.

Particles entering World volume are killed, thus always define layers on top of each other and filled with materials, even if that material is VACUUM.

X-Y top view of a cylindrical diode geometry