The Union_abs_logger_nD McStas Component

12.43 The Union_abs_logger_nD McStas Component

A logger of absorption as events with Monitor_nD options

Identiﬁcation

Author: Mads Bertelsen
Origin: ESS DMSC
Date: 19.06.20

Description

Part of the Union components, a set of components that work together and thus separates geometry and physics within McStas. The use of this component requires other components to be used.

1) One speciﬁes a number of processes using process components 2) These are gathered into material deﬁnitions using Union_make_material 3) Geometries are placed using Union_box/cylinder/sphere, assigned a material 4) Logger and conditional components can be placed which will record what happens 5) A Union_master component placed after all of the above

Only in step 5 will any simulation happen, and per default all geometries deﬁned before this master, but after the previous will be simulated here.

There is a dedicated manual available for the Union_components

This component is an absorption logger, and thus placed in point 4) above.

An absorption logger will log something for each absorption event happening in the geometry or geometries on which it is attached. These are speciﬁed in the target_geometry string. By leaving it blank, all geometries are logged, even the ones not deﬁned at this point in the instrument ﬁle. Multiple geometries are speciﬁed as a comma separated list.

This absorption logger stores absorption as events, with position, velocity, time and weight. The Monitor_nD libraries are used to write the event ﬁles. This version is a close copy of Monitor_nD, having the same interface, though the user must be aware that no propagation happens for rays to hit the detector pixels, instead it uses the position of absorbed. Use the previous keyword to tell Monitor_nD that this is going on. It still needs values set for xwidth and yheight, even though these will not be used.

This absorption logger needs to be placed in space, the position and velocity is recorded in the coordinate system of the logger component.

It is possible to attach one or more conditional components to this absorption logger. Such a conditional component would impose a condition on the state of the neutron after the Union_master component that executes the simulation, and the absorption logger will only record the event if this condition is true.

To use the logger_conditional_extend function, set it to some integer value n and make and extend section to the master component that runs the geometry. In this extend function, logger_conditional_extend[n] is 1 if the conditional stack evaluated to true, 0 if not. This way one can check what rays is logged using regular McStas monitors. Only works if a conditional is applied to this logger.

Input parameters

Parameters in boldface are required; the others are optional.


Name	Unit	Description	Default



target_geometry	string	Comma separated list of geometry names that will be logged, leave empty for all volumes (even not deﬁned yet)	"NULL"
order_total	1	Only log rays that have scattered n times, -1 for all orders	-1
order_volume	1	Only log rays that have scattered n times in the same geometry, -1 for all orders	-1
logger_conditional_extend_index	1	If a conditional is used with this logger, the result of each conditional calculation can be made available in extend as a array called "logger_conditional_extend", and one would then access logger_conditional_extend[n] if logger_conditional_extend_index is set to n	-1
init	string	Name of Union_init component (typically "init", default)	"init"
user0	str	Variable name of USERVAR to be monitored by user0.	""
user1	str	Variable name of USERVAR to be monitored by user1.	""
user2	str	Variable name of USERVAR to be monitored by user2.	""
user3	str	Variable name of USERVAR to be monitored by user3.	""
user4	str	Variable name of USERVAR to be monitored by user4.	""
user5	str	Variable name of USERVAR to be monitored by user5.	""
user6	str	Variable name of USERVAR to be monitored by user6.	""
user7	str	Variable name of USERVAR to be monitored by user7.	""
user8	str	Variable name of USERVAR to be monitored by user8.	""
user9	str	Variable name of USERVAR to be monitored by user9.	""
xwidth	m	Width of detector.	0
yheight	m	Height of detector.	0
zdepth	m	Thickness of detector (z).	0
xmin	m	Lower x bound of opening	0
xmax	m	Upper x bound of opening	0
ymin	m	Lower y bound of opening	0
ymax	m	Upper y bound of opening	0
zmin	m	Lower z bound of opening	0
zmax	m	Upper z bound of opening	0
bins	1	Number of bins to force for all variables. Use ’bins’ keyword in ’options’ for heterogeneous bins	0
min	u	Minimum range value to force for all variables. Use ’min’ or ’limits’ keyword in ’options’ for other limits	-1e40
max	u	Maximum range value to force for all variables. Use ’max’ or ’limits’ keyword in ’options’ for other limits	1e40
restore_neutron	0\|1	Not functional for Union version	0
radius	m	Radius of sphere/banana shape monitor	0
options	str	String that speciﬁes the conﬁguration of the monitor. The general syntax is "[x] options..." (see <b>Descr.</b>).	"NULL"
ﬁlename	str	Output ﬁle name (overrides ﬁle=XX option).	"NULL"
geometry	str	Name of an OFF ﬁle to specify a complex geometry detector	"NULL"
nowriteﬁle	1	If set, logger will skip writing to disk	0
nexus_bins	1	NeXus mode only: store component BIN information <br>(-1 disable, 0 enable for list mode monitor, 1 enable for any montor)	0
username0	str	Name assigned to User0	"NULL"
username1	str	Name assigned to User1	"NULL"
username2	str	Name assigned to User2	"NULL"
username3	str	Name assigned to User3	"NULL"
username4	str	Name assigned to User4	"NULL"
username5	str	Name assigned to User5	"NULL"
username6	str	Name assigned to User6	"NULL"
username7	str	Name assigned to User7	"NULL"
username8	str	Name assigned to User8	"NULL"
username9	str	Name assigned to User9	"NULL"

12.43 The Union_abs_logger_nD McStas Component

Identiﬁcation

Description

Input parameters

Links