Samenvatting

In this report the properties of the E-field sheet have been measured. Also the connection between the E-field
sheet and the pc has been developed. For visualisation of the data a GUI has been made in Matlab which also reads out the data
from the DAQ card. Before a measurement on the clinical equipment can be done the E-field sheet needs to be calibrated.
The calibration process was developed in this report. The relative calibration was done by correcting of an offset and
correcting for a variation in the sensitivity of the diode. To calculate the sensitivity of the diode an antenna was place on
top of a diode and the voltage difference was calculated that was created with the E-field that the antenna was emitting.
The calibration process has an uncertainty that was build up from several parts. These uncertainty parts where the noise in
the signal, the position uncertainty of the antenna, a rotation uncertainty of the antenna in relation to the E-field sheet and
an uncertainty in the temperature. The properties of the special made agar phantoms have been measured. The phantoms are specially made for the E-field sheets, because the agar phantoms are more homogenous then the superstuff phantom already available at the lab. The properties that have been measured from the agar phantom are the heat capacity and the dielectric properties have been measured by an outside lab. The uncertainty in the position sensitivity (1mm variation) was an error of 0.45% in the voltage. The rotation sensitivity gives an error of 0.8% in the voltage for an error of 5°. A variation of 1 Celsius gives a voltage difference of 9mV per Celsius. This all give an uncertainty in the calibration process of 2.5% when it is calibrated with a E-field that give 3V. When the temperature comes above 35 Celsius some of the diodes do not behave linear anymore. Besides to the properties for the E-field sheet the possibility of resolution increase has been looked at, which was found possible because the diodes do not influence each other. Also a calibration routine has been made to calibrate the E-field sheet before use.
The calibration needs to be done every day, because the diodes change in time. For now the calibration in relative which means
the it can accurately give the distribution of the E-field that its in but not the absolute value of the E-field.