# Presentation: 569012

## Race-Track Coil Technology Validation (RT-1) Test Results

- S. Caspi, S. Gourlay,  A. Jackson, _A. Lietzke_, A. McInturff
- Lawrence Berkeley National Laboratory
- Berkeley, Ca. 94720
- VLHC Magnet Technologies Workshop

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## Introduction

- Goal: 14+T VLHC Bending Magnet
- Accelerator Quality
- Reliable
- Affordable
- Path:
- Nb3Sn Race-Track Coils
- Dual-bore Common-Coil
- Economical Coil-Support

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## Magnet Technology Validation

- RD-2 (6 Tesla Proof-Of-Principle)
- Cabling Degradation
- Winding & Reacting 2-Layer Race-track Coils
- Splicing & Potting
- Keyed Coil-Pads (K. Chow)
- Friction Reduction (A. McInturff, A. Lietzke)
- RD-3 (14 Tesla Proof-Of-Principle, 09/00)
- 3-Layer (Conductor Grading)
- Economical Containment

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## RT-1: RD-3 Outer-Coil Validation Test

- 12 T Validation of RD-2 Technology.
- Improved Conductor (Jc > 2000A/mm2).
- Coil “Skinning” (K. Chow).
- Iron  Coil-Islands (R. Gupta).
- Test Conditions:
- Maximum Lorentz Stress (zero bore).
- “Worst-case” coil-support (separation > 5T).

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## RD-3 Outer Coil Parameters

- Nb3Sn Cable:
- 26 x 0.81mm wire
- 59% Cu.
- MJR (Oxford)
- 2-Layer Coils:
- 50 Turns/layer
- Iron coil-island
- 220 mm (bore-bore)
- Mica paper (edges)

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## RD-3 Outer-Coil Pre-stress

- Welded 4.7mm (SS) “Skins”
- 30-40 MPa (Coil Edges)

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## RT-1 Coil-Support 

- Coil-Pads
- 60 x 400mm (SS)
- Cross-Beams
- 120mm (SS)
- Tension Bolts
- 20 @ 38mm (SS)
- Low Pre-stress
- < 16 MPa (300K)

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## RT-1 Test History

- Low (20K) RRR’s
- Coil-1: 13.1, 13.0       Coil-2: 11.7, 11.5

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## RT-1 Coil-Coil Separation

- Coil Displacement

- Bolt-strain

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## RT-1 Quench History

- System Validation
- Training
- Ramp-Rate
- Voltage-Transient

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## Training

- First Try
- 10.2 KA
- 11.8 T
- 96%
- Plateau
- Try #4
- 10.5 KA
- 12.2 T

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## Ramp-Rate Dependence

- 0.9  (11T)
- 33 A/s
- 2.3 T/min
- 0.2 (2.5T)
- Plateau
- 94 A/s
- 6.6 T/min

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## Quenching 

- Quenching

- Training
- Multi-turn
- Simultaneous
- Ramp-rate
- Same
- Both coils

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## Surprise Transient Imbalances

- Voltage
- 120-150 mV
- 0.5 V Imbal.

- Integral
- 0.6-1.0 mV-s
- dB/B=3-5E-4

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## Exceeded Expectations

- No conductor degradation.
- Satisfactory ramp-rate dependence.
- Very good training:
- Despite low RRR.
- Despite low pre-stress.
- Despite compliant support structure.

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00

## Next Steps

- RD-3: Max. Stress (14T) Validation
- Outer + Inner coils
- Iron yoke
- Accelerator-Quality Coil-Support
- RT-2(?): Cost, Je Improvements
- RD-4(?): Harmonic Control.

- AFLietzke@lbl.gov

- VLHC.ppt   05-24-00