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Joined 2026-09-21 Message
Incoming links: Steve R. Domen
Sealed-water calorimeter of Steve R. Domen 2026-11-05
The sealed-water calorimeter of Steve R. Domen is an apparatus for measuring absorbed dose through the radiation-induced temperature rise of a controlled water volume. Domen's 1994 design enclosed the inner water in a thin-walled cylindrical glass vessel about 110 mm long and 33 mm in diameter, immersed in a larger water bath. The vessel also acted as a barrier against convection.[ref]
A Sealed Water Calorimeter for Measuring Absorbed Dose by Steve R. Domen. Section2.1, Design: vessel dimensions, surrounding water and convective-barrier role.
Two calibrated thermistors served as temperature sensors in opposite arms of a Wheatstone bridge, increasing the electrical response to their common temperature rise. The apparatus therefore connected a small thermal change to a measurable resistance change, rather than directly counting radiation events.[ref]
A Sealed Water Calorimeter for Measuring Absorbed Dose by Steve R. Domen. Introduction, Eq1 and Section2: two-thermistor bridge and temperature conversion.
A central experiment compared water fillings with different dissolved-gas conditions. The temperature response could change because radiation also drove chemical reactions, motivating investigation of the heat defect. This comparison illustrates a useful apparatus principle: controlling the geometry and reading the thermometer carefully does not, by itself, establish that every joule deposited in the water becomes measurable heat.[ref]
A Sealed Water Calorimeter for Measuring Absorbed Dose by Steve R. Domen. Abstract and results: repeated measurements with different fillings and heat-defect investigation.
Steve R. Domen 2026-11-05
Steve R. Domen developed physical water calorimetry methods at the National Institute of Standards and Technology. His 1994 sealed-water instrument measured absorbed dose from a minute radiation-induced temperature rise, while investigating how dissolved gases change the fraction of deposited energy that appears as heat.[ref]
A Sealed Water Calorimeter for Measuring Absorbed Dose by Steve R. Domen. Title-page byline, abstract and section 1
The apparatus enclosed water in a thin glass vessel immersed in a larger water tank. Two calibrated thermistors in glass capillaries formed part of a Wheatstone bridge that detected the temperature response. The vessel also limited convection. Comparing different dissolved-gas conditions tested the heat defect, rather than assuming that all absorbed energy immediately becomes heat.[ref]
A Sealed Water Calorimeter for Measuring Absorbed Dose by Steve R. Domen. Sections 2.1–2.3, figures 1–4; abstract, approximately 3700 measurements
For an original ideal calculation, neglect the heat defect and heat transfer during a reading. With water specific heat capacity and measured rise ,This illustrates why sub-millikelvin thermometry matters. It is not a reported run: the real measurement model must include the instrument's corrections and measurement uncertainty.