| 摘要 |
<p>The invention relates to a pocket type digital radiation dosemeter comprising of a detector, which converts the ionisation in the detector caused by the incidence of ionising radiation of certain energy range into electrical impulses, a low power pulse amplifier, that amplifies the electrical pulses from the detector to detectable amplitudes, a discriminator circuit, that is used to reject pulses of origin other than those caused by the ionising radiation, a programmable divider circuit for calibrating the dosemeter, an electronic counting circuit and a six digit LCD display. The sensitivity of the dosemeter is 1 count per νSv (micro Sievert) and the accuracy is within ±15% from 60keV to 1.25 Mev of X or Gamma radiation. A metallic energy compensation filter and a discriminator threshold modulation circuit are used to provide uniform response within ±15% from 60 KeV to 1.25 MeV. The Digital display indicates at any instant the total X or Gamma radiation dose, in νSv, received by the dosemeter since the time at which the dosemeter was switched on. The dosemeter is designed for very low power consumption and is powered by two coin type Li batteries (Type CR2320). It is capable of over 500 hours of continuous operation before having to replace the batteries. A blinking LED indicates low battery condition when 8 hours of battery life is still left. The entire circuitry and the battery holder are mounted on a single printed circuit board. Surface mount components are used to make the unit compact. The dosemeter is compact (110mm L X 30mm W X 14mm H excluding Clip) and light in weight (60 gm).</p> |
