DMSC services Stig Skelboe Project Leader ESS Data Management and Software Center

DMSC services - measurements

Experiment control software Control of instrument Configuration of instrument Sequence of setting Control of sample environment Sequencing of instrument and sample environment settings Logging of settings and detectors Presentation of experiment configuration Authentification of user Remote control of experiments

Data acquisition, event mode High data rates Accelerator/ neutron pulses numbered and characterized Detector electronics, depends on detector type, includes calibration logic Hardware buffers Global instrument clock Separate data network (Gigabit, Infiniband...) Separate data acquisition computers

Neutron detectors 105 – 106 pixels Deadtime ≈ 10 μs 103 – 106 neutrons per pulse (2 ms) 1 neutron event gives 8 Bytes 8 kB – 8 MB in 2 ms 112 kB/s – 112 MB/s

Data rates and volumes Peak per instrument: 100 MB/sec -> 360 GB/h -> 1 TB/measurement Fiber: 10 Gb/sec ~ 1 GB/sec Transfer of 1 TB ~ 1000 sec ~ 17 min Max data per year: 1 PB -> 3 TB/day -> 140 GB/day/instrument

Imaging and tomography Resolution: 4k x 4k -> 16M pixels -> 32 MB 360 angle views: 11 GB 10 sec per view -> 11 GB per hour 3D reconstruction: 4k x 4k x 4k -> 128 GB

Storage system Large data volumes, 1 PB/year Standard format, e.g. Nexus Measurement data and corresponding meta data Controlled access from ”everywhere” Provide all data for analysis steps Seemless interface with analysis software Safe storage, archiving Database with meta data and links to data files ICAT used by ISIS, Diamond, SNS, ANSTO

Bragg’s law nλ=2d sin θ

Neutron Powder Diffractometer at LANSCE

Powder diffraction pattern from spallation source nλ=2d sin θ

Data analysis General tools used with most instruments Instrument specific analysis software Instruments have yet to be determined ESS challenges Exploit event based data Exploit repetition rate multiplication Current development: Mantid ISIS, SNS, HFIR, ILL recently High-performance computing on neutron data Provides a set of common services, algorithms and data objects Instrument or technique independent

Repetition rate multiplication Inelastic scattering: λin ≠λout 100m neutron guide 6-7 choppers 8-10 narrow band pulses for each 2.8 ms pulse λ = 3.9 - 6.2 Å, Δλ = 0.25 Å Inelastic scattering requires narrow band pulses

DMSC services - simulations

Data analysis and simulation Simulation software, e.g. McSTAS To be integrated in analysis framework Used for Training Experiment planning Instrument design Analysis method development Data correction, e.g. for multiple reflections

Theoretical materials modeling Interpretation of measurements using: Classical molecular dynamics Ab-initio molecular dynamics Quantum mechanical methods Density functional theory based Hartree-Fock methods All very compute intensive methods

Thank you ! Stig Skelboe Project Leader ESS Data Management and Software Center