| Field | Value |
|---|---|
| Date | 2026-10-01 |
| Author | Davide Cuneo |
Summary
Discussion with LASA about the high-order prototype (superferric racetrack, sextupole) to be tested at the FREIA-MTF. The test should take place before March 2027. LASA is available for support. Several parameters are still to be confirmed (see open points).
All the data below must be confirmed (specially the mechanics) since they have reports on the final sextupoles and not on the prototypes.
Magnet parameters
| Parameter | Value | Notes |
|---|---|---|
| Type | Superferric racetrack, sextupole | High-order package prototype |
| Height | 235–300 mm | |
| Weight | < 100 kg | |
| Diameter | 350–400 mm | Max 450 mm (?) |
| Inductance | 1.5 H | No curves available |
| Conductor | NbTi | |
| Excitation | The coil excites the iron to produce the real field quality | |
| Nominal current | 99 A | |
| Ultimate current | 111 A | Values for the series, not for the prototype we receive |
| Stored energy | 720 J | |
| Current margin (1.9 K) | 31% on the load line | Not tested at 1.9 K |
| Iss (4.2 K) | 230 A | |
| Ramp rate | 0.5–1 A/s |
Protection and quench detection
- The final version installed at CERN will be self-protected, with the dump on the power supply. For the test of this prototype at LASA they used a dump resistor.
- Dump resistor: 15 Ω, activation in less than 1 ms.
- Differential detection: 300 mV, 20 ms.
- Total voltage detection: 5 V (+ and −), 20 ms (one VT on the left and one on the right).
- 4 VTs (middle, + and −; two in the middle). There is a splice between the 3 coils (+) and the 3 coils (−); splice is not considered.
- HV test probably limited at 100-200 V since the magnet already saw the liquid helium.
Cooldown and cryogenics
- Cooldown from 300 K to 4.2 K with 2 Cernox sensors on top/bottom and 2 on the diameter for monitoring.
- ΔT limit: 100 K/m between top and bottom. The cooldown was slow only for the liquid nitrogen cooldown. After that they evaporate the liquid nitrogen with a heater. Then, they used “warm” helium gas to push out and purge. Finally, they sent liquid helium freely, since below 100 K all the contractions are recovered.
- The prototype has not been tested at 1.9 K.
Mechanics and logistics
- The magnet is not hung: they used a steel frame from which it was suspended.
- Bolted connections for the current leads. They have two small copper wings where to connect the current leads.
- Shipping crate: 100 kg, 54 × 40 × 59 cm.
- Should arrive next friday or at the beginning of the following week.
Open points
- Maximum allowed temperature (or MIITs limit): to be asked.
- Maximum voltage during quench: LASA will provide it.
- Load line / current curves: not available yet.
- Splice details.
- Prototype report: requested, not available maybe
- Send an email to LASA with all the open points.
Next steps
- Test of the IFAST magnet before 30 October 2027. (request from Fernando Toral, CIEMAT). Useful for the MT31 conference.
- LASA available for support during the test.