# Beam parameters

In this section, we'll review the various parameters that need to be configured to work in q-space. **We assume that you've collected all the required information from your beamline scientist (wavelength, PONI, sample-detector distance ...), but you can also find them in the notebook.** We will address the optional case of using a calibration sample to obtain beam information in a next section.

## Beamtime/Experimental Setup

1. Click on `File > Beamtime/Experimental Setup` to open the `Beamtime/Experimental Setup` window.
2. Click on `New Beamtime` and name your experiment. Here, we will usethe name `Tutorial.
   - **Important:** Once created, you must select the new entry in the `Beamtime` list again to edit it.

 We will create two `Experimental Setup` configurations here, one for each value of the out-of-plane detector angle `gamma`.

### Configuration for ${\rm gamma}=-0.75$
In the `Name` field, enter `gamma -0.75` and configure the following parameters:

- Geometry: `GammaDelta`.
- **Sample detector distance**: 350 mm.
- **Wavelength**: 1.24 $\rm A$.
- Beam height/width: Leave as is, not relevant for this case.
- Fraction horiz. polarized: 0.99.
- **Center pixel horizontally/vertically**: This refers to the position of the direct beam on the detector, sometimes called PONIx and PONIy (Point Of Normal Incidence). Use values of 563.5 and 1015.
- Detector rotation around x, y, z: Leave at 0.
- **In-plane/out-of-plane det. angles**: These correspond to `delta` and `gamma`, respectively. Note that due to differing conventions, the delta value from the notebook must be inverted for GIDVis. For example, a notebook value of ${\rm delta} = -8.7$ degrees is entered as ${\rm delta} = 8.7$ in GIDVis. Here, use 8.7 and -0.75 degrees.
- Outer offset: Leave at 0.
- Load the detector properties: Select `Pilatus 1M` from the list in the `Detector` frame and click on `Load`.
- Medium between sample & detector: Set to `He` with a density of 0.

The parameters in **bold** are specific to this tutorial and should be adapted for your experimental setup.

Save the experimental setup, and reselect it from the `Select Experimental Setup` list. The configuration should look like this:

![](images/beam-parameters-beamtime-075.png)

## Create one experimental setup per geometry

Next, create a second `Experimental Setup` for images collected at ${\rm gamma} = -1.4$ degrees.

1. Change the out-of-plane detector angle to -1.4.
2. Update the name to `gamma -1.4`.
3. Save the configuration.

This configuration should look like this:

![](images/beam-parameters-beamtime-14.png)

Be sure to save the configuration and close the window.