# Presentation: 882772

## Magnet Test ResultsTQS01-2 (2nd Thermal Cycle) TQS01-2 Cold Test:  03-04 May 2005LARP Report : 24 May 2005A.F. LietzkeS. Caspi, P.Bish, M. Nyman, W. Lau, A.D. McInturff, R.R. Hafalia, R. HannafordMagnet Test FacilitySuperconducting Magnet GroupLawrence Berkeley National Laboratory

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: 2nd Thermal Cycle

- Test Plan:
- Measure 300K - 4.5K cool-down stresses.
- Measure all pole-turn segment 20K RRR’s.
- Measure strain hysteresis before training.
- Record re-training performance.
- Measure changes in plateau current.
- “Fast-DAQ” views of plateau quench onsets.
- Test date: 03-04 May 2006

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2 Test Results Summary

- RRR:			211(coil6) – 234(coil7)
- 1st quench:		10.3kA (0.84*Iss 7IRs)
- Training quenches:	Pole-turn
- 4.5K plateau: 	10.5kA (0.85*Iss 6Ramp)
- Quench-trigger:	Slip-stick (except plateau)

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## 20K RRR Profiles

- Observe:
- “6Ramp” worse than:
- All neighbors.
- All “Ramps”
- Next worse:
-  “5IRs+Re”.
- Inside of wedge: worse than outside.

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: 2nd Training

- Start:
- 84%
- Coil-7 (ILS)
- Plateau
- 3rd attempt.
- 85%
- “6Ramp” segment (cycle-1)

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: Plateau Quench-Onset

- _Unusual:_
- Negative inductive pre-cursor.
- Inductive surges during propagation.

**Negative precursor**

**PS-SCR transient**

**High-speed onset**

**Inductive surges**

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: Plateau Quench-Onset

- _Repeatable__ signals:_
- 500kHz Q04-07 overlay (neglecting SCR-transients)

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: Plateau Quench-Onset

- _Outer layer__:_
- Relatively quiet
- Pole-segments: very quiet

**Gradual onset: exhausted margin**

**Bumps: small diamagnetic collapses?**

**Increases in flux**

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: Plateau Quench-Onset

- _Outer layer__:_
- Relatively quiet
- Pole-segments: very quiet

**Many late flux changes**

**Many flux-increases**

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: Plateau Quench-Onset

- _Pole-Turn__:_
- ~Gradual onset of “Ramp: dV/dt (exhausted margin?)
- Quiet neighbors (until F-J’s)

**Gradual onset: exhausted margin**

**Bumps: small diamagnetic collapses?**

**Increase in flux in a tiny loop over T-2**

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## “IRS+Re” Loop Detail

- Trace details

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## Summary

- RRR profile:
- “Ramp” is worse than pole-neighborhood.
- “6Ramp” is worst of all “Ramps”.
- Training memory: some, but not phenomenal
- 4.5K plateau: 1% decrease after thermal cycle
- Quench-onset:
- Repeatable.
- “Exhausted-margin”, with diamagnetic collapses.

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## Supported Hypotheses

- RRR profile:
- “Ramps” have some barrier damage.
- “6Ramp” is worst.
- Training rate:
- Dramatic improvement probably requires low pole tension.  Removing gaps is likely insufficient.
- 4.5K plateau:
- Strain-sensitive
- Quench-onset anomalies:
- Unexpected diamagnetic collapses suggests broken filaments in turns 1-5, near “6Ramp-Gap”

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: Plateau Quench-Onset

- _Inner T2-18__:_
- Initial flux decreases (until F-J’s start).

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: Plateau Quench-Onset

- _Outer-layer__:_
- Initial flux decreases (until F-J’s start).

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06

## TQS01-2: Plateau Quench-Onset

- _Multi-turn__:_
- Initial flux:
- T1-5:
- Decreases until FJ’s start.
- T6:
- Relatively quiet

- Superconducting Magnet Group  AFLietzke@lbl.gov

- TQS01 Test Results May'06