Application of a dc SQUID to rf amplification: NQR
Superconducting QUantum Interference Devices (SQUIDs) have been used for more than a decade for the detection of magnetic resonance. Until recently, these devices had mostly been confined to operation in the audiofrequency range, so that experiments have been restricted to measurements of resonance at low frequencies, or of changes in the static susceptibility of a sample induced by rf irradiation at the resonant frequency. However, the recent extension of the operating range of low noise dc SQUIDs to radiofrequencies (rf) allows one to detect magnetic resonance directly at frequencies up to several hundred megahertz. In this paper, we begin by summarizing the properties of dc SQUIDs as tuned rf amplifers. We then describe first, the development of a SQUID system for the detection of pulsed nuclear quadrupole resonance (NQR) at about 30 MHz and second, a novel technique for observing magnetic resonances in the absence of any externally applied rf fields.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA); California Univ., Berkeley (USA). Dept. of Physics
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5083232
- Report Number(s):
- LBL-19653; CONF-8506203-1; ON: DE86001986
- Country of Publication:
- United States
- Language:
- English
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