AE monitoring instrumentation for high performance superconducting dipoles and quadrupoles, Phase II. Progress report, February 1, 1985-January 31, 1986. [Acoustic emission]
In the past year and a half, attention has been focused on the development of instrumentation for on-line monitoring of high-performance superconducting dipoles and quadrupoles. This instrumentation has been completed and satisfactorily demonstrated on a prototype Fermi dipole. Conductor motion is the principal source of acoustic emission (AE) and the major cause of quenches in the dipole, except during the virgin run when other sources are also present. The motion events are mostly microslips. The middle of the magnet is most susceptible to quenches. This result agrees with the peak field location in the magnet. In the virgin state the top and bottom of the magnet appeared acoustically similar but diverged after training, possibly due to minute structural asymmetry, for example differences in clamping and welding strength; however, the results do not indicate any major structural defects. There is good correlation between quench current and AE starting current. The correlation is reasonable if mechanical disturbances are indeed responsible for quench. Based on AE cumulative history, the average frictional power dissipation in the whole dipole winding is estimated to be approx. 10 ..mu..W cm/sup -3/. We expect to implement the following in the next phase of this project: Application of room-temperature techniques to detecting structural defects in the dipole; application of the system to other dipoles and quadrupoles in the same series to compare their performances; and further investigation of AE starting current approx. quench current relationship. Work has begun on the room temperature measurements. Preliminary Stress Wave Factor measurements have been made on a model dipole casing.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge (USA)
- DOE Contract Number:
- AC02-83ER40121
- OSTI ID:
- 5899400
- Report Number(s):
- DOE/ER/40121-6; ON: DE86007414
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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