A design of a four square coil system for a biomagnetic experiment

Herceg, Dejana; Juhas, Anamarija; Milutinov, Miodrag

doi:10.2298/fuee0903285h

Cited by 18 publications

(15 citation statements)

References 3 publications

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“…Here the designations "ZH" and "ZV" correspond to the horizontal and the vertical steering, respectively. The magnetic fields of the pair of the rectangular coils are rather complicated [49][50][51][52]. Here, we apply the single loop approximation to describe the fields of the multiple turn coils.…”

Section: Steering Coil Effects On Beam Trajectorymentioning

confidence: 99%

New halo formation mechanism at the KEK compact energy recovery linac

Tanaka

Nakamura

Shimada

et al. 2018

Phys. Rev. Accel. Beams

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The beam halo mitigation is a very important challenge for reliable and safe operation of a high-energy machine. A systematic beam halo study was conducted at the KEK compact energy recovery linac (cERL) since non-negligible beam loss was observed in the recirculation loop during a common operation. We found that the beam loss can be avoided by making use of the collimation system. Beam halo measurements have demonstrated the presence of vertical beam halos at multiple locations in the beam line (except the region near the electron gun). Based on these observations, we made a conjecture that the transverse beam halo is attributed to the longitudinal bunch tail arising at the photocathode. The transfer of particles from the longitudinal space to a transverse halo may have been observed and studied in other machines, considering nonlinear effects as their causes. However, our study demonstrates a new unique halo formation mechanism, in which a transverse beam halo can be generated by a longitudinal bunch tail due to transverse rf kicks from the accelerating (monopole) fields of the radio-frequency cavities. This halo formation occurs when nonrelativistic particles enter the cavities with a transverse offset, even if neither nonlinear optics nor nonlinear beam effects are present. A careful realignment of the injector system will mitigate the present halo. Another possible cure is to reduce the bunch tails by changing the photocathode material from the present GaAs to a multi-alkali that is known to have a shorter longitudinal tail.

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Section: Steering Coil Effects On Beam Trajectorymentioning

confidence: 99%

New halo formation mechanism at the KEK compact energy recovery linac

Tanaka

Nakamura

Shimada

et al. 2018

Phys. Rev. Accel. Beams

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show abstract

“…The field generation can be either static, time-varying direct current or alternating current depending on the applications requirements. Typical applications include magnetometer calibration, magnetic compass calibration, satellite characterization and biomagnetic studies (Herceg et al, 2009). Square Helmholtz coils can be utilized instead of circular Helmholtz coils in the design, as they provide a wider uniform field of ≈ 5 L parallel to the coils compared to circular coils.…”

Section: Introductionmentioning

confidence: 99%

Tri-axial square Helmholtz coil system at the Alibag Magnetic Observatory: upgraded to a magnetic sensor calibration facility

Mahavarkar¹,

John²,

Dhapre³

et al. 2018

Geosci. Instrum. Method. Data Syst.

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Abstract. A tri-axial square Helmholtz coil system for the study of palaeomagnetic studies, manufactured by GEO-FYZIKA (former Czechoslovakia), was successfully commissioned at the Alibag Magnetic Observatory (IAGA code: ABG) in the year 1985. This system was used for a few years, after which the system encountered technical problems with the control unit. Rectification of the unit could not be undertaken, as the information document related to this system was not available, and as a result the system had been lying in an unused state for a long time, until 2015, when the system was recommissioned and upgraded to a test facility for calibrating the magnetometer sensors. We have upgraded the system with a constant current source and a data-logging unit. Both of these units have been designed and developed in the institute laboratory. Also, re-measurements of the existing system have been made thoroughly. The upgraded system is semi-automatic, enabling non-specialists to operate it after a brief period of instruction. This facility is now widely used at the parent institute and external institutions to calibrate magnetometers and it also serves as a national facility. Here the design of this system with the calibration results for the space-borne fluxgate magnetometers is presented.

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“…The field generation can be either static, time-varying direct current or alternating current depending on the applications re-quirements. Typical applications include magnetometer calibration, magnetic compass calibration, satellite characterization and biomagnetic studies (Herceg et al, 2009). Square Helmholtz coils can be utilized instead of circular Helmholtz coils in the design, as they provide a wider uniform field of ≈ 5 L parallel to the coils compared to circular coils.…”

Section: Introductionmentioning

confidence: 99%

Reply to referee #2

Mahavarkar¹

2018

Preprint

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A tri-axial square Helmholtz coil system for the study of palaeomagnetic studies, manufactured by GEO-FYZIKA (former Czechoslovakia), was successfully commissioned at the Alibag Magnetic Observatory (IAGA code: ABG) in the year 1985. This system was used for a few years, after which the system encountered technical problems with the control unit. Rectification of the unit could not be undertaken, as the information document related to this system was not available, and as a result the system had been lying in an unused state for a long time, until 2015, when the system was recommissioned and upgraded to a test facility for calibrating the magnetometer sensors. We have upgraded the system with a constant current source and a data-logging unit. Both of these units have been designed and developed in the institute laboratory. Also, re-measurements of the existing system have been made thoroughly. The upgraded system is semi-automatic, enabling non-specialists to operate it after a brief period of instruction. This facility is now widely used at the parent institute and external institutions to calibrate magnetometers and it also serves as a national facility. Here the design of this system with the calibration results for the space-borne fluxgate magnetometers is presented.

show abstract

A design of a four square coil system for a biomagnetic experiment

Cited by 18 publications

References 3 publications

New halo formation mechanism at the KEK compact energy recovery linac

New halo formation mechanism at the KEK compact energy recovery linac

Tri-axial square Helmholtz coil system at the Alibag Magnetic Observatory: upgraded to a magnetic sensor calibration facility

Reply to referee #2

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