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

2. DMSC services - measurements

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. Bragg’s law
nλ=2d sin θ

10. Neutron Powder Diffractometer at LANSCE

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

12. 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

13. 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 = Å, Δλ = 0.25 Å
Inelastic scattering requires narrow band pulses

14. DMSC services - simulations

15. 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

16. 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

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