Low-Noise Pulsed Pre-Polarization Magnet Systems for Ultra-Low Field NMR

被引：7

作者：

Sims, James R. ^{[1
]}

Schillig, Josef B. ^{[1
]}

Swenson, Charles A. ^{[1
]}

Gardner, David L. ^{[1
]}

Matlashov, Andrei N. ^{[1
]}

Ammerman, Curtt N. ^{[1
]}

机构：

[1] Los Alamos Natl Lab, Los Alamos, NM 87545 USA

来源：

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY | 2010年 / 20卷 / 03期

关键词：

Johnson noise; litz; perfluorocarbon pre-polarization; ULF-NMR;

D O I：

10.1109/TASC.2010.2040613

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

A liquid cooled, pulsed electromagnet of solenoid configuration suitable for duty in an ultra-low field nuclear magnetic resonance system has been designed, fabricated and successfully operated. The magnet design minimizes Johnson noise, minimizes the hydrogen signal and incorporates minimal metal and no ferromagnetic materials. In addition, an acoustically quiet cooling system permitting 50% duty cycle operation was achieved by designing for single-phase, laminar flow, forced convection cooling. Winding, conductor splicing and epoxy impregnation techniques were successfully developed to produce a coil winding body with integral cooling passageways and adequate structural integrity. Issues of material compatibility, housing, coolant flow system and heat rejection system design will be discussed. Additionally, this pulsed electromagnet design has been extended to produce a boiling liquid cooled version in a paired solenoid configuration suitable for duty in an ultra-low field nuclear magnetic resonance system. This pair of liquid nitrogen cooled coils is currently being tested and commissioned. Issues of material compatibility, thermal insulation, thermal contraction, housing and coolant flow design are discussed.

引用

页码：752 / 755

页数：4

共 4 条

[1] SQUID detected NMR in microtesla magnetic fields [J].