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US3600583A
Expired / Lapsed
US
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Apparatus and methods for reading thermoluminescent dosimeters and the like
Assignee: VIC ACQUISITION Corp
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Filing: 1969-03-24
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Granted: 1971-08-17
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Expires: 1989-03-24
Abstract
Abstract Thermoluminescent dosimeter reader in which dose measurements are based on the glow curve peak. Measurements are made by comparing the output of a photomultiplier tube with the analogconverted state of a digital counter, the comparison being performed by alternately connecting a capacitor to the output of the digital-to-analog converter and to the signal from the photomultiplier, periodically, in order to produce error pulses which are amplified in an AC amplifier and which advance the counter when the sense of the error indicates that the signal is greater than the counter state. A two-speed clock controls the sampling frequency at which measurements are performed, so that the signal source is isolated from the measurement circuit most of the time, and the counter is advanced rapidly when the signal exceeds the counter state. Range change circuitry inserts a shunting impedance in the input of the comparator when the counter fills to capacity, resets the counter, and actuates an indicator connected to the counter.
Inventors
- 👤 Donald A Paynter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:01
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/02; G01T1/10; G01T1/11; G01T1/115; G01T7/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
87 words
Apparatus for reading the peak output of a thermoluminescent dosimeter or the like, comprising means for heating said dosimeter, means for producing an electrical signal proportional to the light output of the dosimeter, a digital counter, a digital-to-analog converter connected to the output of said counter, means for periodically comparing said signal and the output of said converter and producing an output pulse when said signal is greater than the output of said converter for advancing said counter, and means for indicating the state of said counter.
Claim 2
Dependent Claim
87 words
Apparatus for reading the peak output of a thermoluminescent dosimeter or the like, comprising means for heating said dosimeter, means for producing an electrical signal proportional to the light output of the dosimeter, a digital counter, a digital-to-analog converter connected to the output of said counter, means for periodically comparing said signal and the output of said converter and producing an output pulse when said signal is greater than the output of said converter for advancing said counter, and means for indicating the state of said counter.
Claim 3
Dependent Claim
85 words
Apparatus in accordance with claim 1, wherein said comparing means has two-speed clock means for controlling the periodic comparison, said clock means being responsive to said output pulse of said comparing means for increasing the rate of operation of said clock means, whereby when said comparing means produces said output pulses, the signal and the output of said converter are compared more frequently in order to permit said counter to be advanced more rapidly when the signal is greater than the output of the converter.
Claim 4
Dependent Claim
28 words
Apparatus in accordance with claim 1, further comprising range change means for reducing the signal input to said comparing means when said counter has counted to its capacity.
Claim 5
Dependent Claim
25 words
Apparatus in accordance with claim 3, wherein said range change means comprises means for resetting said counter when said counter has counted to its capacity.
Claim 6
Dependent Claim
26 words
Apparatus in accordance with claim 3, wherein said range change means has associated therewith means for controlling said indicating means to indicate a change of range.
Claim 7
Dependent Claim
20 words
Apparatus in accordance with claim 5, wherein said means associated with said range change means comprises decimal point indicator means.
Claim 8
Dependent Claim
34 words
Apparatus in accordance with claim 3, wherein said range change means comprises a sequencer for inserting different range impedances into the input of said comparing means when said counter counts to its capacity successively.
Claim 9
Dependent Claim
59 words
Apparatus in accordance with claim 1, wherein said comparing means comprises an AC amplifier with a capacitor connected to its input and means for connecting said capacitor alternately to the output of said converter and to said signal in order to produce a change iN charge upon said capacitor constituting said pulse when the signal exceeds the converter output.
Claim 10
Dependent Claim
25 words
Apparatus in accordance with claim 8, there being a threshold circuit interposed between the output of said AC amplifier and the input of said counter.
Claim 11
Dependent Claim
20 words
Apparatus in accordance with claim 1, said counter being responsive to pulses of one polarity but not the opposite polarity.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-16 | 1975-02-15 | 1975-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-16 | 1979-02-15 | 1979-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-16 | 1983-02-15 | 1983-08-17 | $7700.00 | Window Closed / Lapsed |