US4312224A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Absorbed dose water calorimeter
Assignee: Government of the United States of America
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Filing: 1980-02-29
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Granted: 1982-01-26
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Expires: 2000-02-29
Abstract
Abstract An absorbed dose water calorimeter that takes advantage of the low thermal diffusivity of water and the water-imperviousness of polyethylene film. An ultra-small bead thermistor is sandwiched between two thin polyethylene films stretched between insulative supports in a water bath. The polyethylene films insulate the thermistor and its leads, the leads being run out from between the films in insulated sleeving and then to junctions to form a Wheatstone bridge circuit. Convection barriers may be provided to reduce the effects of convection from the point of measurement. Controlled heating of different levels in the water bath is accomplished by electrical heater circuits provided for controlling temperature drift and providing adiabatic operation of the calorimeter. The absorbed dose is determined from the known specific heat of water and the measured temperature change.
Inventors
- 👤 Steve R. Domen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:23
CPC Classifications
G; G01; G01K; G01K17/00; G01T; G01T1/00; G01T1/02; G01T1/12
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
86 words
A calorimeter-radiation dosimeter for measuring an absorbed dose profile comprising: a container for a liquid; sensing means for sensing temperature at a predetermined location in said container; insulative means supporting said sensing means at said predetermined location; and means responsive to said sensing means for providing an indication representing the temperature at said predetermined location; wherein said insulative means comprises a pair of thin plastic sheets which are impervious to said liquid, said pair of sheets being tightly sandwiched together with said sensing means between them.
Claim 2
Dependent Claim
86 words
A calorimeter-radiation dosimeter for measuring an absorbed dose profile comprising: a container for a liquid; sensing means for sensing temperature at a predetermined location in said container; insulative means supporting said sensing means at said predetermined location; and means responsive to said sensing means for providing an indication representing the temperature at said predetermined location; wherein said insulative means comprises a pair of thin plastic sheets which are impervious to said liquid, said pair of sheets being tightly sandwiched together with said sensing means between them.
Claim 3
Dependent Claim
31 words
The apparatus according to claim 1 further comprising means for slightly changing the temperature of the liquid in said container by changing an electrical current through the liquid in said container.
Claim 4
Dependent Claim
22 words
The dosimeter according to claim 1 wherein said plastic sheets are polyethylene sheets having a thickness no greater than 30 micrometers each.
Claim 5
Dependent Claim
20 words
The dosimeter according to claim 3 wherein said sheets are slightly stretched across and supported between two insulative frame members.
Claim 6
Dependent Claim
74 words
The dosimeter according to claim 4 further comprising heating means for heating selected regions of water near said predetermined location, said heating means comprising: a plurality of additional frame members stacked above and below said two frame members; a plurality of spaced individual sheets of plastic film stretched across respective frame members to define said selected regions between adjacent individual sheets; and means for selectively passing electrical current through water in said selected regions.
Claim 7
Dependent Claim
61 words
The dosimeter according to claim 5 wherein said last-named means comprises: voltage supply means; a pair of terminal means disposed on each of said frames at opposite ends of a respective selected region; switch means for selectively connecting said voltage supply means across said each pair of terminal means; and means for selectively adjusting the voltage of said voltage supply means.
Claim 8
Dependent Claim
14 words
The dosimeter according to claim 6 wherein said terminal means are thin metal strips.
Claim 9
Dependent Claim
22 words
The dosimeter according to claims 1 or 2 further comprising heating means for heating selected regions of water proximate said predetermined location.
Claim 10
Dependent Claim
31 words
The dosimeter according to claim 1 wherein said last-mentioned means comprises a Wheatstone bridge circuit having four circuit arms and wherein said thermistor is connected in one of said circuit arms.
Claim 11
Dependent Claim
16 words
The dosimeter according to claim 1 further comprising thermal insulation means surrounding said container of water.
Claim 12
Independent Claim
91 words
A method of measuring absorbed radiation dose comprising the steps of: (a) directing a radiation beam into a liquid bath; (b) interposing a temperature sensing means in the path of said beam at a predetermined location in said bath by supporting the sensing means between two thin sheets of plastic material sandwiched together at said predetermined location to insulate the sensing means from the surrounding liquid; and (c) measuring the temperature rise brought about by the beam at said predetermined location by monitoring changes in the output of said sensing means.
Claim 13
Independent Claim
91 words
A method of measuring absorbed radiation dose comprising the steps of: (a) directing a radiation beam into a liquid bath; (b) interposing a temperature sensing means in the path of said beam at a predetermined location in said bath by supporting the sensing means between two thin sheets of plastic material sandwiched together at said predetermined location to insulate the sensing means from the surrounding liquid; and (c) measuring the temperature rise brought about by the beam at said predetermined location by monitoring changes in the output of said sensing means.
Claim 14
Dependent Claim
32 words
The method according to claim 11 further comprising the step of determining the absorbed radiation dose at said predetermined location from the measured temperature rise and the known specific heat of water.
Claim 15
Dependent Claim
54 words
The method according to claim 11 further comprising the steps of changing the level in said bath with a minimum of disturbance by pouring liquid into a container located outside the bath and connected to the bath by a flexible tube and utilizing a micrometer measurement of the change in depth in the bath.
Claim 16
Dependent Claim
27 words
The method according to claim 11 further comprising the step of selectively heating different locations in said water bath to minimize temperature drift at said predetermined location.
Claim 17
Dependent Claim
20 words
The method according to claim 11 wherein said step of heating comprising passing an electric current through said different locations.
Claim 18
Dependent Claim
35 words
The method according to claim 11 further comprising the steps of: rapidly raising or lowering the temperature of the water with immersion heaters or coolers; and agitating the water to produce a uniform water temperature.
Claim 19
Dependent Claim
30 words
The method according to claim 11 further comprising the step of slightly changing the temperature of the liquid to decrease temperature drifts by changing an electrical current through the bath.
References Cited (Backward Citations)
US2802986A
Cited
US3670570A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-25 | 1985-07-27 | 1986-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-25 | 1989-07-27 | 1990-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-25 | 1993-07-27 | 1994-01-26 | $7700.00 | Window Closed / Lapsed |