In this paper we present results concerning the performance exhibited by an integrated array of 32 one-dimensional amorphous silicon thin film position sensitive detectors based on nip and hetero amorphous silicon structures, with a total active area size below 1 cm2 linearity, its spatial resolution and response time, that make it one of the most interesting analog detector to be used in unmanned optical inspection control systems where a continuous detection process is required. This opens a wide range of applications for amorphous silicon devices in the area of image processing. © 2002 Elsevier Science B.V. All rights reserved.

A new experimental procedure combining usual isothermal DC charging and discharging with non-isothermal current measurements has been recently proposed. It is mainly suitable for very high insulating polymers and it was successfully applied to the study of space charge trapping and transport in low-density polyethylene. The analysis of the isothermal currents revealed the presence of different traps whose characteristic (de)trapping times can be deduced. The isothermal procedures allowed the selective charging of the sample. By choosing the charging field and the ratio of charge/discharge times, non-isothermal analysis permitted the differentiation of three or four peaks (at approximate to50degreesC, approximate to65degreesC, approximate to70degreesC and approximate to85degreesC) associated with charge detrapping from surface or near-surface (<20 mum) traps. These traps have activation energies between 0.21 and 1.54 eV. The mobility at 30degreesC is around 5 x 10(-16) m(2) V-1 s(-1). Samples had to be conditioned before each experiment in order to obtain reproducible results.

A new experimental procedure combining usual isothermal DC charging and discharging with non-isothermal current measurements has been recently proposed. It is mainly suitable for very high insulating polymers and it was successfully applied to the study of space charge trapping and transport in low-density polyethylene. The analysis of the isothermal currents revealed the presence of different traps whose characteristic (de)trapping times can be deduced. The isothermal procedures allowed the selective charging of the sample. By choosing the charging field and the ratio of charge/discharge times, non-isothermal analysis permitted the differentiation of three or four peaks (at approximate to50degreesC, approximate to65degreesC, approximate to70degreesC and approximate to85degreesC) associated with charge detrapping from surface or near-surface (<20 mum) traps. These traps have activation energies between 0.21 and 1.54 eV. The mobility at 30degreesC is around 5 x 10(-16) m(2) V-1 s(-1). Samples had to be conditioned before each experiment in order to obtain reproducible results.

Low density polyethylene (LDPE) films kept in a sodium chloride aqueous solution, were aged under a high AC electrical field. The films were prepared from press moulding of LDPE pellets with small amounts of antioxidants. The dielectric spectra at 30 degreesC in the range of 10(-5) Hz to 105 Hz were obtained prior and after ageing. Three different experimental techniques were used to obtain the full spectrum. For the low frequency (LF) region (10(-5) Hz to 10(-1) Hz) the time domain technique was used (charge and discharge currents were also measured). The measuring device used for the 10(-1) Hz to 10(1) Hz medium frequency (MF) region was a lock-in amplifier. While for the high frequency (HF), 10(-1) Hz to 10(5) Hz, RLC bridge measurements were performed. Differences can be seen between aged and unaged PE. The region showing less changes with ageing is the MF region where the peak of the unaged samples seems to become less defined with ageing time. This peak is probably due to additives and impurities (such as antioxidants) that will tend to slowly diffuse out with time. The LF peak is a broad peak related to localised space charge injection driven by the electric field. This peak increases in an earlier stage of ageing decreasing afterwards possibly when the polymer becomes more conductive. Finally the HF shows the beginning of a peak due to gamma and beta transitions. The later is related to dipolar rotation of carbonyl groups in amorphous polymer regions, while the former is associated to crankshaft motions in the main polymer chain. This peak decreases with ageing disappearing for the most aged samples. This could also be explained if the sample becomes more conductive.