1. List of terms and abbreviations

BAM

Beam arrival monitor, monitors the time when the FEL beam arrives.

BDA

Beam distribution area (behind the gas monitor detector).

bunch charge

The total charge of an electron microbunch.

CAMP chamber

CFEL ASG multipurpose chamber, with CFEL being the Center for Free-Electron Laser.

DLD

Delay line detector, measures the (x,y) positions of electrons by two pairs of timing difference measurements.

GMD

Gas monitor detector, measures the intensity of the FEL beam before and after the gas attenuator. It contains the parts before (GMD_Tunnel) and after (GMD_BDA) the FEL undulator tunnel. Technical details of the detector see [Tiedke08].

FEL

Free electron laser.

HEXTOF analyzer

High energy X-ray time of flight analyzer. A measurement device that records simultaneously the (kx, ky, E) coordinates of the photoelectrons emitted within the X-ray photoemission horizon. It is later rebranded and sold by SPECS GmbH under the name METIS.

SASE

Self-amplified spontaneous emission.

ToF

Time of flight.

macrobunch

A macroscopic bunch of electrons which can possess substructures (i.e. microbunches). It is the operating unit of a high-gain FEL and also referred to colloquially as a pulse train. Each macrobunch of electrons is tagged by the macrobunch ID.

microbunch

A subunit of a high-gain FEL pulse train due to spatial redistribution and localization of electrons within a macrobunch – a phenomenon called micronbunching. Each microbunch of electrons is tagged by a microbunch ID. A well-behaving FEL has a stable number of microbunches within a macrobunch, although the total microbunch number can vary between beam time slots due to change in the machine parameters.

dd

Dask dataframe – a parallelized version of the pandas dataframe.

run number

Integer label of an experimental run. Every scan shares a single run number.

file number

Integer label of a file in an experimental run.

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Bibliography

[Tiedke08] Gas-detector for X-ray lasers. pdf