A cryogenic current comparator for the absolute measurement of nA beams

Peters, A.; Vodel, W.; Koch, H.; Neubert, R.; Reeg, H.; Schroeder, C.

doi:10.1063/1.56997

Cited by 24 publications

(8 citation statements)

References 5 publications

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“…By using a Cryogenic Current Comparator (CCC) based on a low-T c SQUID with a ferromagnetic Vitrovac core in the pick-up loop, a resolution of ~6 pA/√Hz at 4.2 K and 2 kHz with a system 10-kHz frequency bandwidth has been achieved for monitoring accelerated electrons or 20 Ne 10+ ions [36]. The sensor part of the CCC was optimized for the lowest possible noise-limited current resolution, in combination with a high system bandwidth of ~200 kHz, without compromising the resolution [37].…”

Section: Low-tc and High-tc Squid Nde Systemsmentioning

confidence: 99%

Superconducting Quantum Interferometers for Nondestructive Evaluation

Faley

Kostyurina

Kalashnikov

et al. 2017

Sensors

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We review stationary and mobile systems that are used for the nondestructive evaluation of room temperature objects and are based on superconducting quantum interference devices (SQUIDs). The systems are optimized for samples whose dimensions are between 10 micrometers and several meters. Stray magnetic fields from small samples (10 µm–10 cm) are studied using a SQUID microscope equipped with a magnetic flux antenna, which is fed through the walls of liquid nitrogen cryostat and a hole in the SQUID’s pick-up loop and returned sidewards from the SQUID back to the sample. The SQUID microscope does not disturb the magnetization of the sample during image recording due to the decoupling of the magnetic flux antenna from the modulation and feedback coil. For larger samples, we use a hand-held mobile liquid nitrogen minicryostat with a first order planar gradiometric SQUID sensor. Low-Tc DC SQUID systems that are designed for NDE measurements of bio-objects are able to operate with sufficient resolution in a magnetically unshielded environment. High-Tc DC SQUID magnetometers that are operated in a magnetic shield demonstrate a magnetic field resolution of ~4 fT/√Hz at 77 K. This sensitivity is improved to ~2 fT/√Hz at 77 K by using a soft magnetic flux antenna.

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Section: Low-tc and High-tc Squid Nde Systemsmentioning

confidence: 99%

Superconducting Quantum Interferometers for Nondestructive Evaluation

Faley

Kostyurina

Kalashnikov

et al. 2017

Sensors

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“…There is precedent for using squids in the magnetically noisy accelerator environment. (14) However, the beam spectrum has never been explored at this level of sensitivity, and there is concern that unexpected noise or signals might exist. Because of the large dynamic range of the squid, the narrow filter bandwidth, and the possibility of background subtraction, a good measurement can be accomplished in the presence of significant noise and background.…”

Section: Resultsmentioning

confidence: 99%

Squids, snakes, and polarimeters: A new technique for measuring the magnetic moments of polarized beams

Cameron

Luccio

Shea

et al. 1997

AIP Conference Proceedings

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Effective polarimetry at high energies in hadron and lepton synchrotrons has been a long standing and difficult problem. In synchrotrons with polarized beams it is possible to cause the direction of the polarization vector of a given bunch to alternate at a frequency which is some subharmonic of the rotation frequency. This can result in the presence of lines in the beam spectrum which are due only to the magnetic moment of the beam, and which are well removed from the various lines due to the charge of the beam. The magnitude of these lines can be calculated from first principles. They are many orders of magnitude weaker than the Schottky signals. Measurement of the magnitude of one of these lines would be an absolute measurement of beam polarization. For measuring magnetic field, the Superconducting Quantum Interference Device, or squid, is about five orders of magnitude more sensitive than any other transducer. Using a squid, such a measurement might be accomplished with the proper combination of shielding, pickup loop design, and filtering. The resulting instrument would be fast, nondestructive, and comparatively cheap. In addition, techniques developed in the creation of such an instrument could be used to measure the Schottky spectrum in unprecedented detail. We present specifics of a polarimeter design for RHIC, and briefly discuss the possibility of using this technique to measure polarization at high energy electron machines like LEP and HERA.

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“…Apart from applications in fields such as high energy accelerators, ion implantation and other charged particle beam instruments [92] this use is directed in the longer term at a precision measurement of the Faraday constant F which relates to the SI definition of the amount of substance and the Avogadro constant N via the relationship…”

Section: For Non-invasive Sensing Of Charged Particle Beamsmentioning

confidence: 99%