The materials requirement inside a magnetic gradiometer is stringent because the presence of magnetic susceptible material will introduce intrinsic errors into the device. Many commercial grade non-magnetic materials still have unacceptably high levels of magnetic susceptibility between 10 and 10. It is shown here that machining with steel tools can further increase the susceptibility by up to ...

A sample holder for high temperature (300 K<T<800 K) measurements in superconducting quantum interference device magnetometers is presented. It is fabricated using aluminum foil and it is appropriate for samples in either solid or powder form. The holder is homogeneous for the gradiometer coil, and this results in a contribution to the background signal that is below the instrument noise at any...

Using spin-echo NMR techniques we study the transverse spin relaxation of hyperpolarized liquid 129Xe in a spherical cell. We observe an instability of the transverse magnetization due to dipolar fields produced by liquid 129Xe, and find that imperfections in the pi pulses of the spin-echo sequence suppress this instability. A simple perturbative model of this effect is in good agreement with t...

SQUID systems, using either high temperature or low temperature superconductors, were developed for sensitive measurements in magnetically disturbed environments. They include the SQUIDs and fast SQUID electronics. Magnetometer SQUID systems are used for geophysical sounding, where they show superiority when compared to conventional induction coils for very deep sounding or fast measurement. Hi...

Clandestine mine reconnaissance is the Navy's highest MCM priority. During the 1980's, the Superconducting Gradiometer/Magnetometer Sensor (SGMS) was demonstrated in the Magnetic and Acoustic Detection of Mines (MADOM) ATD to provide effective detection/classification capabilities, especially against buried mines, and to reduce significantly acoustic false alarms arising from bottom clutter [1]...

Scalar atomic magnetometers have many attractive features but their sensitivity has been relatively poor. We describe a Rb scalar gradiometer using two multipass optical cells. We use a pump-probe measurement scheme to suppress spin-exchange relaxation and two probe pulses to find the spin precession zero crossing times with a resolution of 1 psec. We realize a magnetic field sensitivity of 0.5...

Applications of optical magnetometers in demanding environments require a high common-mode rejection ratio (CMRR) to effectively suppress ambient noise, but challenges still remain achieve experimental sensitivity at the quantum noise level. The authors develop compact magnetic gradiometer featuring CMRR and differential tens femtoteslas over broad dynamic range, including Earth's field magnitu...