A magnetic field sensor has internal power supply generating circuits to generate a higher operating voltage for a magnetic field sensing element, resulting in a magnetic field sensor with improved sensitivity to magnetic fields. In the above formula, R1, R2 R3, R4, R5, R6 and Ar are defined herein. The x-ray detector assembly further includes a plurality of x-ray scintillator elements arranged in an array. The connector is connected to the antenna and configured to connect a transaction card to the antenna in response to at least insertion in the housing. The at least one antivibration element has a first end secured to the first housing part and a second end secured to the second housing part.