DREAM instrument view

This notebook is a simple example of how to use the instrument view for the DREAM instrument.

• The DREAM-specific instrument view is capable of slicing the data with a slider widget along a dimension (e.g. tof) by using the dim argument.

• There are also checkboxes to hide/show the different elements that make up the DREAM detectors.

We begin with relevant imports. We will be using tutorial data downloaded with pooch. If you get an error about a missing module pooch, you can install it with !pip install pooch:

import scipp as sc
from ess import dream
import ess.dream.data  # noqa: F401

Load the data

We load a dataset from a Geant4 simulation (stored as a .csv file). In each detector bank, the data is organised by wire, strip, module, segment, and counter. The high resolution detector also has an additional sector dimension.

dg = dream.io.load_geant4_csv(dream.data.get_path("data_dream0_new_hkl_Si_pwd.csv.zip"))
dg = dg["instrument"]  # Extract the instrument data

# Extract the events from nested data groups
dg = sc.DataGroup({key: detector["events"] for key, detector in dg.items()})
dg

Downloading file 'data_dream0_new_hkl_Si_pwd.csv.zip' from 'https://public.esss.dk/groups/scipp/ess/dream/1/data_dream0_new_hkl_Si_pwd.csv.zip' to '/home/runner/.cache/ess/dream/1'.

scipp.DataGroup

(module: None, segment: None, counter: 2, wire: None, strip: None, sector: 4, sumo: 4)

• mantle

  scipp

  DataArray

  (module: 7,
   segment: 6,
   counter: 2,
   wire: 32,
   strip: 256)

  DataArrayView

  binned data [len=13, len=8, ..., len=0, len=0]
• high_resolution

  scipp

  DataArray

  (sector: 4,
   module: 9,
   segment: 8,
   counter: 2,
   wire: 16,
   strip: 32)

  DataArrayView

  binned data [len=0, len=0, ..., len=0, len=0]
• sans

  scipp

  DataArray

  (sector: 4,
   module: 9,
   segment: 8,
   counter: 2,
   wire: 16,
   strip: 32)

  DataArrayView

  binned data [len=0, len=0, ..., len=0, len=0]
• endcap_backward

  scipp

  DataArray

  (sumo: 4,
   module: 13,
   segment: 10,
   counter: 2,
   wire: 16,
   strip: 16)

  DataArrayView

  binned data [len=13, len=10, ..., len=4, len=3]
• endcap_forward

  scipp

  DataArray

  (sumo: 4,
   module: 13,
   segment: 10,
   counter: 2,
   wire: 16,
   strip: 16)

  DataArrayView

  binned data [len=0, len=0, ..., len=0, len=1]

Full instrument view

We first histogram the data along the time-of-flight (tof) dimension, making sure the same bins are used for all elements:

tof_edges = sc.linspace("tof", 1.0e7, 1.0e8, 51, unit="ns", dtype=int)
data = dg.hist(tof=tof_edges)

We now use the instrument_view function to show the 3D view of the instrument pixels, specifying that we wish to have a slider along the tof dimension:

full_view = dream.instrument_view(data, dim="tof")
full_view

Note that it is possible to use any dimension for the slider instead of tof, such as wavelength (if present in the data).

Displaying individual detector elements

It is also possible to view a single detector element, selecting e.g. mantle from the original data:

mantle_view = dream.instrument_view(dg["mantle"].hist(tof=50), dim="tof")
mantle_view

The instrument view is designed to be flexible in terms of what it accepts as input. This means that you can easily inspect, for example, a single module by using the usual slicing notation for data arrays.

Below, we display the first module in the backward end-cap detector:

dream.instrument_view(dg["endcap_backward"]["module", 0].hist(tof=1))