TE-EPC News, 26/04/2018

GPS & REX Consolidation 2018

In the framework of the consolidation program, one power converter used for the ISOLDE GPS line (for separator magnet) and three power converters used in REX-ISOLDE (for 1x separator magnet and 2x steering magnets) have been replaced.
This upgrade allows the replacement of ageing power converters and the FGC3 controller implementation with the new class 63, which now integrates the B-Field regulation loop.

1. ISOLDE GPS Mass Separator power converter changes
 

 
ISOLDE GPS power converter for separator magnet YGPS.RDS.3000 (before and after)

  Before After
Power converter type BRUKER MN42/200 (+200A - +42V) COBALT_SWITCH (±200A - ±50V)
Topology Transformer + rectifier + linear output stage Switching
Current accuracy 20 ppm from Bruker user guide
200 ppm measured
100 ppm
Spare No Yes – Electro-mechanic
Remote control G64-1553 (till 2015)
Ether-FGC3 (since 2015)
Ether-FGC3
Bipolarity
(for ISOLDE negative ion run)
No Yes
B-Field loop location BRUKER BH15 (till 2015)
FESA virtual device (since 2015)
FGC3

2. REX-ISOLDE power converters changes
 

 
REX-ISOLDE power converter for separator and steering magnets (before and after)

2.1 Separator magnet: XSEP.RB.0100

Improvements - changes:

  Before After
Type Bouhnik AF99032 (+60A - +20V) CANCUN-50 (±50A - ±30V)
Topology Transformer + rectifier + linear output stage Switching
Current accuracy 20 ppm from Bouhnik user guide - not measured 20 ppm
Spare No Yes
Remote control PLC Profibus DP Ether-FGC3
Bipolarity (not requested) No Yes
B-Field loop location FESA virtual device (since 2004) FGC3

 

2.2 Steering magnet: XL9GP.RCV.0400

Improvements - changes:

  Before After
Type CERN nCOD (±3.5A - ±80V) CUTE (±12.5A - ±15V)
Topology Switching + linear output stage Switching
Current accuracy 200 ppm 200 ppm
Spare No Yes
Remote control PLC Profibus DP Ether-FGC3
Bipolarity (not requested) Yes Yes

3. Field Regulation

The DC mode operation on ISOLDE facilities, bending beam elements for mass separator purpose and several isotopes to be extract at different fields values needs field regulation of magnets when non-linearity between current and field is too big to be ignored and cannot be easily compensated (e.g. thermal derivation).


FGC3 B-Field loop control achitecture



GPS mass scan with YGPS.RDS.3000 magnet controlled with FGC3 B-field regulation

Reporting from Nicolas David
TE-EPC-FPC