Reliably Cooling Accelerators
The Australian Synchrotron
Dr Don McGilvery
Lead Accelerator Operator

Reliably cooling Accelerators
Its easy, just flow some cool water through whatever you wish to cool.
But• If there is too little flow -> melt things• If there is too much flow -> erode things• If the pH is too low or too high -> corrode things• If the oxygen level is too high -> oxidise things• If the oxygen level is too low -> strip protective oxide layer• If the temperature is not stable -> dimensional instabilities• If temperature is too low or too high -> leaks• If the conductivity is too high or too low -> corrosion
At the Australian Synchrotron we have tried to implement worlds bestpractise to eliminate, or at least minimise the disruption caused bycooling water problems.

Beam Availability during Scheduled User TimeMelted HOM Damper in SRRF Cavity

Two of the SRRF
cavities showing
the extra flow
meters added after
the meltdown

Flow Meters used for Storage Ring LCW

Stainless Steel construction, no moving parts, remote digital readout
Differential Pressure with Hall effect monitor

Failure Modes of Flow meters
Have experienced greater than 20% failure rate•
•••
••
•

PCB failure (change to non-Pb solder)
Radiation Damage
Magnet coming loose
Earth leakage
Failure to read Zero at zero flow
High non-linearity
Susceptibility to strong magnet fields

Better reliability if the meters are operated at flows near 50% flow range
Also have ongoing problems with fouling of flow control valves
Required a simple and reliable way to test meters.

Testing Flow Meters by closing valves

Drop in flow over a 4 day period

The trip point was 0.8 l/m

LCW Trend GUI(matlab script accessing EPICS database)

Select a duration and sampling interval
Fit a line and calculate time to LOLO or HIHI
Highlight those < 4 weeks
Click on an entry to graph trend

Storage Ring Low Conductivity Water Control

By changing the pressure (with no beam) it is possible to vary the flow

Photon Stop flow meters output as overall flow reducedNote•SR01 deviates low•SR12 deviates highthen fails at 50%•There is about a 30%
variation between meters

Display of Flows and LOLO trip pointsDisplay of bad LOLO trip point(SR12FE01FLM04:FLOW_STATUS)

Plot of Flow Meter showing bad behaviour
Two days after collecting
the data, (before we hadanalysed it) we had a beam
dump caused by anintermittent flow meter
trip in Front End 12.
Looking back at the flow
test data it was easy toidentify the suspect meter.

Comparison of PLC set points
and Observed Trip Points
The ID front end flow meters tripped at the values set in the PLCs.
(SR12FE01FLM02 didn't hit its LOLO setpoint. and SR12FE01FLM04 was bad)

SR03

SR05SR08

SR12SR13SR14

FE01FLM01 5.0\ 4.9

5.0\ 5.0

16.0\15.9

5.0\ 4.9

5.0\ 5.0

5.0\ 5.0

FE01FLM02 5.0\ 4.9

5.0\ 4.9

5.0\ 4.9

5.0\ NaN

5.0\ 4.9

5.0\ 4.9

FE01FLM03 16.0\16.0

16.0\15.9

16.0\16.0

6.0\15.8

16.0\15.9

16.0\16.0

FE01FLM04 5.0\ 5.0

5.0\ 4.9

16.0\15.8

5.0\26.6

5.0\ 4.9

5.0\ 5.0(PLC Trip Setpoint\Trip Value)

Injection System Flow Switches
Stainless Steel bodies
Springs and magnets exposed to LCW
Problems
ContaminationPlunger Sticking
Springs eroding
Magnets dissolving
Fouling of flow control valves
We will do similar testing of trip pointsof these switches.

CreditGraham Harding for suggesting to vary the pump speed to vary the flows
Robbie Clarken for the Matlab scripts

Australian Synchrotron
www.synchrotron.org.au