Software-based data acquisition and processing for neutron detectors at European Spallation Source—early experience from four detector designs

Abstract

A: European Spallation Source (ESS) will deliver neutrons at high flux for use in diverse neutron scattering techniques. The neutron source facility and the scientific instruments will be located in Lund, and the Data Management and Software Centre (DMSC), in Copenhagen. A number of detector prototypes are being developed at ESS together with its European in-kind partners, for example: SoNDe, Multi-Grid, Multi-Blade and Gd-GEM. These are all position sensitive detectors but use different techniques for the detection of neutrons. Except for digitization of electronics readout, all neutron data is anticipated to be processed in software. This provides maximum flexibility and adaptability and allows deep inspection of the raw data for commissioning which will reduce the risk of starting up new detector technologies. But it also requires development of high performance software processing pipelines and optimized and scalable processing algorithms. This report provides a description of the ESS system architecture for the neutron data path. Special focus is on the interface between the detectors and DMSC which is based on UDP over Ethernet links. The report also describes the software architecture for detector data processing and the tools we have developed, which have proven very useful for efficient early experimentation, and can be run on a single laptop. Processing requirements for the SoNDe, Multi-Grid, Multi-Blade and Ge-GEM detectors are presented and compared to event processing rates archived so far.

From micro- to macro- neutron sources: The Lund Broad-band Neutron Facility

“…Source-based continuous neutron beams from an 241 Am/Be source provide stable fluxes of typically 10 6 n/s. At the LBNF, these beams have been successfully used for response characterizations of neutron detectors [2,3,4] and their data-acquisition systems [5]. Using a technique called "tagging" and the infrastructure present at the LBNF, it is even possible to study attenuation and detector responses as function of the neutron energy even with standard radioactive sources [6,7,8].…”

Architecture of the data aggregation and streaming system for the European Spallation Source neutron instrument suite

“…from the raw detector data [5]. Figure 2 shows a screenshot of the detector commissioning tool Daquiri [6] with examples of event data before and after processing by the EFU.…”

“…As a result of the high neutron beam brightness, the expected event data rates for ESS instruments are correspondingly high. Each detector pixel identifier and timestamp will be encoded in a pair of 32-bit numbers [7]; using these values, table 1 presents estimates of the data rates expected to be sent from the EFUs into the aggregation and streaming system [5]. As the table shows, expected rates cover a range of almost three orders of magnitude, from 10 MB/s to 4 GB/s.…”

First neutron data recorded at the V20 Test Instrument utilizing prototype chopper systems and beam monitors planned for ESS

“…The top layer served by EPICS are the scientific user interfaces and ancillary functionalities provided by Data Management and Software Centre (DMSC). These final but important layers are allowing the data acquisition [20], the event formation [21], the instrument control, the data reduction [22], monitoring, scientific data analysis and data archiving. For the purpose of testing novel neutron methods as well as hardware and software solutions that are relevant for future instruments, ESS is operating a dedicated neutron time-of-flight test beamline (the V20 Test Instrument) at Helmholtz-Zentrum Berlin.…”