ELECTRONIC SYSTEM FOR MEASUREMENT OF RADIATION-SENSITIVE MOS DEVICES
A low-power wireless ionizing radiation measurement system is present that is intended to be used in a wearable dosimeter for occupational radiation monitoring. An apparatus is provided comprising a switching interface, wherein the switching interface alternates between a first switching state and a second switching state. In the first switching state, a radiation-sensitive metal oxide semiconductor capacitor (MOSCAP) is coupled to an external biasing source. In the second switching state, the radiation-sensitive MOSCAP is coupled with reversed polarity relative to the first switching state to a capacitive readout circuit to thereby allow for high-resolution real-time electronic measurement of a radiation-induced capacitance response.
1 . An apparatus comprising:
a switching interface,
wherein the switching interface alternates between a first switching state and a second switching state,
wherein in the first switching state, a radiation-sensitive metal oxide semiconductor capacitor (MOSCAP) is coupled to a biasing source,
wherein in the second switching state, the radiation-sensitive MOSCAP is coupled with reversed polarity relative to the first switching state to a capacitive readout circuit to thereby allow for high-resolution real-time electronic measurement of a radiation-induced capacitance response.
2 . The apparatus of claim 1 , wherein the switching interface alternates between the first switching state and the second switching state dynamically in response to a state of the radiation-sensitive MOSCAP.
3 . The apparatus of claim 1 , wherein the switching interface alternates between the first switching state and the second switching state statically in response to a pre-programmed user input.
4 . The apparatus of claim 3 , wherein the switching interface alternates between the first switching state and the second switching state dynamically in response to one or more internal system states and/or external environmental parameters.
5 . The apparatus of claim 1 , wherein during the second switching state a voltage across a depletion region of the radiation-sensitive MOSCAP remains between a bias voltage provided by the external biasing source and a threshold voltage of the radiation-sensitive MOSCAP.
6 . The apparatus of claim 1 , wherein the first switching state enhances sensitivity of the radiation-sensitive MOSCAP.
7 . The apparatus of claim 6 , wherein the sensitivity is enhanced by ensuring operation in an inversion operation region of the radiation-sensitive MOSCAP.
8 . The apparatus of claim 1 , wherein the second switching state enhances measurement resolution of the radiation-sensitive MOSCAP.
9 . The apparatus of claim 8 , wherein the second switching state enhances measurement by ensuring measurement in a depletion region of the radiation-sensitive MOSCAP.
10 . An apparatus comprising:
one or more radiation-sensitive metal oxide semiconductor capacitors (MOSCAPs) configured to generate a radiation-induced capacitance response;
an external biasing source configured to increase sensitivity of the radiation-induced capacitance response of the one or more radiation-sensitive MOSCAPs;
a capacitive readout circuit configured for high-resolution, real-time electronic measurement of the radiation-induced capacitance response of the one or more radiation-sensitive MOSCAPs; and
a switching interface configured to alternate between a first switching state and a second switching state,
wherein in the first switching state, a radiation-sensitive metal oxide semiconductor capacitor (MOSCAP) is coupled to an external biasing source,
wherein the second switching state enhances measurement by ensuring measurement in a depletion region of the radiation-sensitive MOSCAP.
11 . The apparatus of claim 10 , wherein in the second switching state, the radiation-sensitive MOSCAP is coupled with reversed polarity relative to the first switching state to a capacitive readout circuit to thereby allow for high-resolution real-time electronic measurement of the radiation-induced capacitance response.
12 . The apparatus of claim 10 , wherein an output of the capacitive readout circuit comprises a discharge time ratio of reference capacitor and radiation-sensitive MOSCAP for the one or more radiation-sensitive MOSCAPs.
13 . The apparatus of claim 12 , wherein the output of the capacitive readout circuit comprises a discharge time ratio of a reference capacitor and the one or more radiation-sensitive MOSCAPs averaged over a prescribed number of samples to thereby generate a low noise readout of the radiation-induced capacitance response of the one or more radiation-sensitive MOSCAPs.
14 . The apparatus of claim 13 , wherein a measurement resolution for the capacitance response of the one or more radiation-sensitive MOSCAPs is improved by increasing the prescribed number of samples.
15 . The apparatus of claim 13 , wherein a Signal-to-Noise (SNR) ratio associated with a measured capacitance response of the one or more radiation-sensitive MOSCAPs is proportional to a square root of the prescribed number of samples.
16 . The apparatus of claim 15 , wherein a measurement precision is 20 times greater than a measurement precision obtained with a C-V meter.
17 . The apparatus of claim 10 , wherein the capacitive readout circuit comprises an application specific integrated circuit (ASIC) configured for measurement of the capacitance response of the one or more radiation-sensitive MOSCAPs.
18 . An apparatus comprising:
one or more radiation-sensitive metal oxide semiconductor capacitors (MOSCAPs) configured to generate a radiation-induced capacitance response;
a biasing source configured to increase the sensitivity of the radiation-induced capacitance response of the one or more radiation-sensitive MOSCAPs;
a capacitive readout circuit configured for high-resolution, real-time electronic measurement of the radiation-induced capacitance response of the one or more radiation-sensitive MOSCAPs; and
a switching interface configured to alternate between a first switching state and a second switching state,
wherein in the first switching state, a radiation-sensitive metal oxide semiconductor capacitor (MOSCAP) is coupled to an external biasing source,
wherein in the second switching state, the radiation-sensitive MOSCAP is coupled with reversed polarity relative to the first switching state to a capacitive readout circuit to thereby allow for high-resolution real-time electronic measurement of the radiation-induced capacitance response; and
a microprocessor/wireless transceiver integrated-circuit (IC) for processing, storage and transmission of an output of the capacitive readout circuit to a base station for further signal processing and reporting.
19 . The apparatus of claim 18 , wherein the transmission occurs over a wireless link established to the base station when the microprocessor/wireless transceiver IC is in a vicinity of the base station.
20 . The apparatus of claim 18 , further comprising a temperature sensing element for compensating temperature of the radiation-induced capacitance response.
21 . The apparatus of claim 18 , further comprising an accelerometer.
22 . The apparatus of claim 21 , wherein the accelerometer is configured to implement a wake-up function.
23 . The apparatus of claim 22 , wherein the accelerometer is configured within a wearable device.
24 . The apparatus of claim 23 , wherein an output of the accelerometer indicates whether the device is worn by a user during radiation exposure.
25 . The apparatus of claim 23 , wherein the apparatus is configured so that the apparatus goes into an ultra-low-power mode and wakes up when motion of the apparatus exceeds a predetermined threshold.