# 3.3.1.33. NXmonitor¶

**Status**:

base class, extends NXobject

**Description**:

## A monitor of incident beam data. ...

A monitor of incident beam data.

It is similar to the NXdata groups containing monitor data and its associated axis coordinates, e.g. time_of_flight or wavelength in pulsed neutron instruments. However, it may also include integrals, or scalar monitor counts, which are often used in both in both pulsed and steady-state instrumentation.

**Symbols**:

No symbol table

**Groups cited**:

**Structure**:

@default: (optional) NX_CHAR## Declares which child group contains a path leading ...

Declares which child group contains a path leading to a NXdata group.

It is recommended (as of NIAC2014) to use this attribute to help define the path to the default dataset to be plotted. See https://www.nexusformat.org/2014_How_to_find_default_data.html for a summary of the discussion.

mode: (optional) NX_CHAR## Count to a preset value based on either clock time (timer) ...

Count to a preset value based on either clock time (timer) or received monitor counts (monitor).

Any of these values:

`monitor`

|`timer`

start_time: (optional) NX_DATE_TIMEStarting time of measurement

end_time: (optional) NX_DATE_TIMEEnding time of measurement

preset: (optional) NX_NUMBER {units=NX_ANY}preset value for time or monitor

distance: (optional) NX_FLOAT {units=NX_LENGTH}

DEPRECATED: Use transformations/distance insteadDistance of monitor from sample

range: (optional) NX_FLOAT (Rank: 1, Dimensions: [2]) {units=NX_ANY}Range (X-axis, Time-of-flight, etc.) over which the integral was calculated

nominal: (optional) NX_NUMBER {units=NX_ANY}Nominal reading to be used for normalisation purposes.

integral: (optional) NX_NUMBER {units=NX_ANY}Total integral monitor counts

type: (optional) NX_CHARAny of these values:

`Fission Chamber`

|`Scintillator`

time_of_flight: (optional) NX_FLOAT (Rank: same as field efficiency, Dimensions: same as field efficiency) {units=NX_TIME_OF_FLIGHT}Time-of-flight

efficiency: (optional) NX_NUMBER (Rank: same as field i, Dimensions: same as field i) {units=NX_DIMENSIONLESS}Monitor efficiency

data: (optional) NX_NUMBER (Rank: dataRank) {units=NX_ANY}Monitor data

sampled_fraction: (optional) NX_FLOAT {units=NX_DIMENSIONLESS}Proportion of incident beam sampled by the monitor (0<x<1)

count_time: (optional) NX_FLOAT {units=NX_TIME}## Elapsed actual counting time, can be an array of size ``np`` ...

Elapsed actual counting time, can be an array of size

`np`

when scanning. This is not the difference of the calendar time but the time the instrument was really counting, without pauses or times lost due beam unavailability

depends_on: (optional) NX_CHAR

integral_log: (optional) NXlogTime variation of monitor counts

GEOMETRY: (optional) NXgeometry

DEPRECATED: Use the field depends_on and NXtransformations to position the monitor and NXoff_geometry to describe its shape insteadGeometry of the monitor

OFF_GEOMETRY: (optional) NXoff_geometryThis group describes the shape of the beam line component

TRANSFORMATIONS: (optional) NXtransformations## This is the group recommended for holding the chain of translation ...

This is the group recommended for holding the chain of translation and rotation operations necessary to position the component within the instrument. The dependency chain may however traverse similar groups in other component groups.

## Hypertext Anchors¶

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.