The improved ARTEMIS IV multichannel solar radio spectrograph of the University of Athens

We present the improved solar radio spectrograph of the University of Athens operating at the Thermopylae Satellite Telecommunication Station. Observations now cover the frequency range from 20 to 650 MHz. The spectrograph has a 7-meter moving parabola fed by a log-periodic antenna for 100 650 MHz and a stationary inverted V fat dipole antenna for the 20 100 MHz range. Two receivers are operating in parallel, one swept frequency for the whole range (10 spectrums/sec, 630 channels/spectrum) and one acousto-optical receiver for the range 270 to 450 MHz (100 spectrums/sec, 128 channels/spectrum). The data acquisition system consists of two PCs (equipped with 12 bit, 225 ksamples/sec ADC, one for each receiver). Sensitivity is about 3 SFU and 30 SFU in the 20 100 MHz and 100 650 MHz range respectively. The daily operation is fully automated: receiving universal time from a GPS, pointing the antenna to the sun, system calibration, starting and stopping the observations at preset times, data acquisition, and archiving on DVD. We can also control the whole system through modem or Internet. The instrument can be used either by itself or in conjunction with other instruments to study the onset and evolution of solar radio bursts and associated interplanetary phenomena.Comment: Experimental Astronomy, Volume 21, Issue 1, pp.41-5

General development of a new hall effect sensor

Silicon Hall plates show an offset of a few millitesla. A large portion of this offset is caused by mechanical stress in the device. The offset can be reduced with a factor 103 to 105 when the spinning - current principle is applied. This paper presents a structure of a new Hall effect sensor which uses a novel offset reduction method and the function which governs the changes in the electric field inside the new Hall effect sensor in presence of magnetic field. This function helps us to control in MatLab environment the equipotential lines and to monitor the changes when biasing conditions are change. The combination of his form and the elaborate sequence of using dynamic spinning current technique, can lead to satisfactory results of produced Hall voltage with small noise in a presence of external magnetic field. © 2011 IFSA

Introducing a new hall effect sensor - Novel dynamic offset reduction method

Silicon Hall plates show an offset of a few millitesla. A large portion of this offset is caused by mechanical stress in the device. The offset can be reduced when the spinning-current principle is applied. In this paper we present a model and numerical analysis of a new Hall effect sensor which using a novel offset reduction method. We call it "Wheel Hall Senor" and senses all 3 filed dimensions. The flux-density of BZ is proportional to the DC component of the output signal, whereas the BX and BY components are proportional to the first harmonic of the output signal. Furthermore we calculate the function which governs the changes in the electric field inside the new Hall effect sensor in presence of magnetic field. This function help us to control in MatLab environment the equipotential lines and to monitor the changes in biasing conditions. About the new sensor, the combination of his pioneering form and the elaborate sequence of using the dynamic spinning current technique, could be lead to satisfactory results of produced Hall voltage with small noise in a presence of external magnetic field