The Oxrop data analysis software package

OxRop is a data analysis package that was initially designed for the requirements of the CRESST II dark matter experiment. It has since expanded beyond its original purpose, and can now read not only CRESST but EDELWEISS experimental data, as well as the data formats used in Technische Universität München in Garching, Institut de Physique Nucléaire in Lyon, and squid magnetometry data from the CryoEDM experiment. OxRop is an objected orientated program built in C++ using the ROOT framework. This gives access to the ROOT interpreter and graphical capabilities providing flexibility for interactive, bespoke analyses.

OxRop contains all the tools necessary to move from raw experimental data from a generic, multi-detector dark matter experiment to a final yield plot, including pulse fitting and parameter determination, energy calibration, cuts, frequency analysis, mathematical parameter operations as well as general histogram and graph functionality.

The future for OxRop is to become the data analysis package for the future EURECA experiment.

Features

Oxrop takes input data is the form of events, which can be a collection of signal pulses recorded by a CRESST detector, scintillation events from a photomultiplier tube, or a magnetic field measurement over a fixed time period. The program then calculates a large number of parameter, such as pulse height, rise time, average value, for all events. The following options are then available to display and analyse the data:

• Event display: View single or multiple events.
• Histograms: Plot 1D or 2D histograms or any combination of parameters.
• Cuts: Select events meeting specific criteria
• Mathematical operations: To calculate new parameters from existing ones.
• Standard pulses: An accurate calculation of the pulse height is done by creating a template pulse by summing a large number of pulses produced by a calibration source.
• CPE: Converting pulse height to energy is a procedure to determine the energy of events recorded by CRESST detectors, using the signals produce by test pulses, generated by sending a current pulse to the detector heater.
• FFT: Calculates the Fourier spectrum of event data.
• Parametric fit: Fits a given function to a data pulse, to determine (for example) the rise and decay times of different components.
• Advanced cut. A first step towards an automatic blind analysis, the advantaged cut identifies contaminant events in CRESST data due to detector noise, pile-up, SQUID resets, and other effects.
• Macros: As oxrop is fully integrated with the ROOT environment, macros can easily be written to carry out analysis tasks.

Applications

• CRESST: oxrop was designed to analyse the data from the 33 phonon and light detectors for CRESST phase II.
• Scintillation studies: oxrop has been adapted to analyse scintillation pulses recorded by photomultiplier tubes, as part of the MPC analysis.
• Magnetometer: oxrop is used to analysis data from SQUID and fluxgate magnetometers in the cryoEDM experiment.
• EDELWEISS: oxrop has been adapted to read data taken by the EDELWEISS dark matter experiment. We anticipate it will be used as the analysis program for EURECA.

Other software

Oxrop is part of an extended suite of software developed by our group. Other programmes include:

• DaqClient: A data acquisition programme, designed to interface with a wide range of hardware. DaqClient is used to record magnetometry data for cryoEDM, as well as for scintillation studies (with photomultipliers), and cryogenic detector tests in Oxford.
• SquidClient: An application written to tune and control and 66 SQUID sensors for CRESST II. Also used for cryoEDM and other SQUID tests.