  Hydrogenated amorphous silicon (a-Si:H) is a material having an intrinsically
high radiation hardness that can be deposited on flexible substrates like
Polyimide. For these properties a-Si:H can be used for the production of
flexible sensors. a-Si:H sensors can be successfully utilized in dosimetry,
beam monitoring for particle physics (x-ray, electron, gamma-ray and proton
detection) and radiotherapy, radiation flux measurement for space applications
(study of solar energetic particles and stellar events) and neutron flux
measurements. In this paper we have studied the dosimetric x-ray response of
n-i-p diodes deposited on Polyimide. We measured the linearity of the
photocurrent response to x-rays versus dose-rate from which we have extracted
the dosimetric x-ray sensitivity at various bias voltages. In particular low
bias voltage operation has been studied to assess the high energy efficiency of
these kind of sensor. A measurement of stability of x-ray response versus time
has been shown. The effect of detectors annealing has been studied. Operation
under bending at various bending radii is also shown.
