ESS Timing System Plans and Requirements

Timo KorhonenChief Engineer, Integrated Control System Division

www.europeanspallationsource.seMay 19, 2014

The European Spallation Source

• An accelerator-based neutron source to be built in Lund, southern Sweden– Material and life sciences research

• A collaboration of 17 European nations– Construction budget about 1860 million Euro

• Targeted to be the world’s most powerful neutron source– 5 MW beam power, 2.5 GeV proton energy, 14 Hz

repetition rate, 2.86 ms pulse@50 mA beam current– 22 neutron beam lines in construction budget

• First neutrons in 2019, full configuration in 2025

X-Ray Image

Neutron radiograph

Neutron scattering of hydrogen in a metal organic framework

Where Will ESS Be Built?

• ESS is located in southern Sweden adjacent to MAX-IV (A 4th generation light source)

• To provide a world-class material research center for Europe

What will ESS look like?

Linac

TargetInstruments

What is Different About ESS?

• The average proton beam power will be 5 MW– Average neutron flux is

proportional to average beam power

– 5 MW is five times greater than SNS beam power

• The total proton energy per pulse will be 360 kJ – Beam brightness (neutrons per

pulse) is proportional to total proton energy per pulse

– 360 kJ is over 20 times greater than SNS total proton energy per pulse

What does 5 MegaWatts mean?

• At 5 MegaWatts, – one beam pulse

• has the same energy as a 16 lb (7.2kg) shot traveling at – 1100 km/hour– Mach 0.93

• Has the same energy as a 1000 kg car traveling at 96 km/hour

• Happens 14 x per second– You boil 1000 kg of ice

in 83 seconds• A ton of tea!!!

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ESS Control System

• ESS Integrated Control System Division (ICS) is in charge of building the control system(s) for the accelerator, the neutron target, and providing controls for the beamline components

• EPICS as the control system software• Project scope includes also

– protection systems (Machine, Personnel)– Global timing system for site-wide synchronization

• Some parts of the controls will be provided by ESS partner laboratories as in-kind contributions– e.g., proton source and LEBT controls by Saclay (France)– More to come

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Timing system requirements

• Accelerator parameters for timing– Front end frequency is 352 MHz (CERN Standard)– High energy section is at 704 MHz– Master oscillator at 88 MHz

• (even if we could divide from 352 MHz)– Repetition rate 14 Hz

• Dictated by neutron choppers• No need to do AC sync (I was told)

– Repetition rate must be programmable • No RF pulsing when no beam (power consumption)• But “some” devices need still 14 Hz triggers (?? Needs clarification.)

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Timing system requirements

• Typical requirements for a pulsed accelerator– Triggering of devices– Synchronous acquisition and data handling

• Long pulses mean a lot of data per pulse!– Distributing beam parameters

• Machine mode: where will the beam go (target, tuning dump)• Beam mode: pulse intensity, length

– Repetition rate control• Possibly even single pulses – if possible

– Timestamping of data– Some top-level requirements are still under discussion…

• ESS challenge:– Interfacing with the machine protection system– Ensuring that machine and beam modes are propagated correctly to all

receivers

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Timing system requirements

• The typical requirements are “easy”– 14 Hz vs 100 Hz (or higher) repetition rate– Long pulses create some issues in data handling

• For control system in general, not too much for timing

• More work in software side– Ramping up the beam power; intensity and pulse length– Beam mode handling– Beam synchronous data handling

• Interfacing to MPS is critical– Or, find a way to make MPS totally independent

• I cannot yet imagine how that could be done in a reasonable way

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Issues to be considered

• Synchronizing with “slow” devices with no EVR– PLCs, etc. – We need to be able to correlate data – NTP server in EVG IOC? Is it sufficient?

• Handling user’s devices– Oscilloscopes, etc. (known issue)

• Access to API & hardware interfaces?– Purpose-built devices: detectors, etc.

• No standard interfaces• There is still time to think about this, though.

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Summary

• ESS timing requirements are not too different from other pulsed accelerators

• Machine protection is a big issue, though– One single mis-steered pulse will break the machine

• Platform (form factor) is pending final decision– Lots of push for microTCA, though– How to integrate other devices?

• Project timespan is an issue– We are building now something that will be in full use after 10 years, and

have an expected lifetime of 40 years– Roadmap for upgrades and technology refresh

• Collaboration is very much appreciated!– Sharing of knowledge, applications, ideas…