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.
GPS & REX Consolidation 2018
1. ISOLDE GPS Mass Separator power converter changes
| 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
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
