Radiation measuring system using transister flux sensors

Claim 2

Radiation dosimeter apparatus comprising: a saturable PN junction quiescently biased into forward conduction and located to receive an unknown sub microsecond pulse of radiation from an ionizing radiation source; means for measuring the time required after termination of said radiation pulse for said PN junction to return from saturated condition to said quiescent forward biased condition; predetermined correlating means, relating saturation time with radiation intensity, for converting the measured saturation time to a measure of radiation intensity.

Claim 3

The apparatus of claim 1 wherein said PN junction is a portion of a junction transistor.

Claim 4

The apparatus of claim 2 wherein said correlating means includes means for relating junction saturation times less than 500 microseconds and radiation source pulses of less than 100 nanoseconds duration to measures of radiation intensity.

Claim 5

The apparatus of claim 2 further including a plurality of radiation receiving junction transistors dispersed through a work sample subjected to said radiation pulse.

Claim 6

The apparatus of claim 1 wherein said means for measuring includes a second PN junction located to receive a lesser intensity of said pulse radiation and connected to generate an output signal identifying the termination of said radiation pulse and the commencement of said saturation time.

Claim 7

The apparatus of claim 5 wherein said second PN junction is comprised of a PIN diode.

Claim 8

The apparatus of claim 5 wherein said saturable PN junction and said second PN junction are each part of junction transistors.

Claim 9

The apparatus of claim 1 wherein said apparatus is responsive to radiation from a flash X-ray source.

Claim 10

The apparatus of claim 1 wherein said apparatus is responsive to radiation from a detonated nuclear device.

Claim 11

The apparatus of claim 1 wherein said predetermined correlating means includes an inverse natural logarithim relationship.

Claim 12

The apparatus of claim 1 wherein said PN junction comprises a semiconductor junction diode.

Claim 15

The method of claim 12 wherein said step of timing saturation persistence includes exposing a PN junction to a nonsaturating attenuated intensity of said pulse of ionizing radiation and starting said timing at an output signal transition of said PN junction.

Claim 16

The method of claim 13 wherein said step of timing includes counting transitions of a high frequency signal between on and off gatings thereof by said signal transition and the end of said saturation condition.

Claim 17

Radiation dosimeter apparatus comprising a bipolar junction sensing transistor having collector-base and base-emitter semiconductor junctions; means for forward biasing said base-emitter junction and reverse biasing said collector-base junction; means for exposing said transistor to a pulse of ionizing radiation energy; means for measuring the radiation induced saturation time in said transistor; predetermined means relating said measured saturation time with measures of radiation intensity.

Claim 18

Radiation dosimeter apparatus comprising a bipolar junction sensing transistor having collector-base and base-emitter semiconductor junctions; means for forward biasing said base-emitter junction and reverse biasing said collector-base junction; means for exposing said transistor to a pulse of ionizing radiation energy; means for measuring the radiation induced saturation time in said transistor; predetermined means relating said measured saturation time with measures of radiation intensity.

Claim 19

The apparatus of claim 15 further including a radiation responsive non saturating first calibration transistor and a radiation saturable second calibration transistor.

Claim 20

The apparatus of claim 16 wherein said first and second calibration transistors are located in close proximity in a different radiation receiving location than said sensing transistor.

Claim 21

The apparatus of claim 17 including a plurality of said junction sensing transistors each located in a radiation receptive location attending a test specimen.

Claim 22

The apparatus of claim 18 further including a plurality of current probe means, one for each said transistor, for sensing signal current transitions in said transistors.

Claim 23

The apparatus of claim 15 wherein said means for forward biasing is located in an area of attenuated radiation.

Claim 24

The apparatus of claim 15 wherein said bipolar junction sensing transistor is a low frequency transistor.

Claim 25

The apparatus of claim 21 further including load means connected in series with the collector terminal of said sensing transistor collector-base junction for limiting the saturation current in said collector-base junction.

Claim 26

The apparatus of claim 22 wherein said predetermined means relating saturation time is correlated with the electrical value of a load resistance in said load means.

Claim 27

The apparatus of claim 22 wherein said means for measuring includes means responsive to said saturation time for gating a high frequency signal and means for counting cycles of said high frequency signal during the period of said gating.

Claim 28

Radiation dosimeter apparatus for measuring the intensity of pulsed submicrosecond ionizing radiation received by a specimen comprising: PN junction means for generating a first electrical signal identifying the starting and terminating transitions of a received radiation pulse and a second electrical signal having a predetermined amplitude relationship with the peak intensity of said received radiation; first radiation saturable junction transistor means located adjacent said PN junction means and biased to have a predetermined quiescent collector current flow for generating a first saturation signal starting at one of said radiation transition signals and having predetermined duration correlation with the peak intensity of said received radiation and with the amplitude of said second electrical signal; second radiation saturable junction transistor means similar in characteristics to said first radiation saturable means and located in a predetermined position of interest with respect to said specimen and biased to a predetermined quiescent collector current flow, for generating a second saturation signal starting at one of said radiation transition signals and having predetermined duration correlation with the intensity of said received ionizing radiation; means including a predetermined correlation between saturation time and radiation intensity for generating a radiation intensity signal from said second saturation signal.

Claim 29

Radiation dosimeter apparatus for measuring the intensity of pulsed submicrosecond ionizing radiation received by a specimen comprising: PN junction means for generating a first electrical signal identifying the starting and terminating transitions of a received radiation pulse and a second electrical signal having a predetermined amplitude relationship with the peak intensity of said received radiation; first radiation saturable junction transistor means located adjacent said PN junction means and biased to have a predetermined quiescent collector current flow for generating a first saturation signal starting at one of said radiation transition signals and having predetermined duration correlation with the peak intensity of said received radiation and with the amplitude of said second electrical signal; second radiation saturable junction transistor means similar in characteristics to said first radiation saturable means and located in a predetermined position of interest with respect to said specimen and biased to a predetermined quiescent collector current flow, for generating a second saturation signal starting at one of said radiation transition signals and having predetermined duration correlation with the intensity of said received ionizing radiation; means including a predetermined correlation between saturation time and radiation intensity for generating a radiation intensity signal from said second saturation signal.

Claim 30

The apparatus of claim 25 wherein said PN junction means includes a radiation responsive non saturable second transistor means.

Claim 31

The apparatus of claim 26 including a plurality of said radiation saturable junction transistor means each located at positions of interest with respect to said specimen for sensing radiation intensity at a plurality of specimen locations.

Claim 32

The apparatus of claim 27 wherein said plurality of transistor means includes junction transistors of predetermined similar characteristics.

Claim 33

The apparatus of claim 28 wherein said plurality of transistor means includes a plurality of junction transistors taken from the same substrate wafer.

Claim 34

The apparatus of claim 29 wherein said transistors are low frequency silicon transistors.

Claim 35

The apparatus of claim 30 wherein said transistors are of the power amplifier type.

Claim 36

The apparatus of claim 27 further including multiplex switching means for communicating measured saturation time data to a common processor.