Two-dimensional position-sensing PVDF dust detectors for measurement of dust particle trajectory, velocity, and mass

Abstract

We have extended our development of polyvinylidene fluoride (PVDF) dust detectors to include the capability for determination of the x, y coordinates of particle entry into the PVDF detector. The two-dimensional position-sensing PVDF dust detectors ( x, y detectors) we have developed employ resistive charge division, and have a set of conducting strips on the front surface and an orthogonal set on the back surface. Our earlier measurements on PVDF x, y detectors made use of a laser to simulate dust particle impacts. These measurements have recently been extended to include impacts from accelerated dust particles. Two 6 μm thick 58 cm 2 PVDF x, y detectors were placed in a telescope arrangement for measurement of particle time-of-flight, trajectory and fragmentation. We present the dust particle results and show that dust particle impact coordinates are measured by the PVDF x, y detectors with typical errors of −1−3 mm for x and y (over most of the detector sensitive area), confirming the results obtained with the laser. We also show that the model we developed earlier to describe signal pulse generation and the occurrence of anomalous currents (i.e., polarity reversal with time) in Si x, y detectors responding to energetic charged nuclei also applies to PVDF x, y detectors responding to hypervelocity dust particles. Finally, we show that even if particle fragmentation occurs upon penetration of the first x, y detector, particle trajectory is still measured, but with a larger position error (∼ 4–6 mm) in the second x, y detector due to the spread of fragment impact positions on the second x, y detector.