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Showing papers on "Calorimeter published in 1987"


Journal ArticleDOI
Richard Wigmans1
TL;DR: In this article, the role of the electromagnetic to hadronic signal ratio e h is examined in detail, and various components that contribute to the signal from a hadron calorimeter, and the factors that affect the energy resolution with which hadrons can be detected, are examined.
Abstract: The various components that contribute to the signal from a hadron calorimeter, and the factors that affect the energy resolution with which hadrons can be detected, are examined in detail. The role of the electromagnetic to hadronic signal ratio e h is crucial in this respect. Its value is determined by the Z of the absorber material, the thickness of the passive and active layers, the signal integration time of the detector, and the properties of the readout material, in particular the free proton content and the saturation or recombination properties for few-MeV proton detection. Readout media that contain free protons offer the possibility to tune the e h ratio to the desired value (1.0) through the sampling fraction. Signal equalization ( e h = 1.0) does not seem to be a property unique to 238U, but can also be achieved for lead and even iron calorimeters. The calculations show, on the other hand, that e h values are larger than 1.0 for any calorimeter using liquid-argon readout. The intrinsic energy resolution for hadron detection is largely dominated by fluctuations in the binding energy losses that occur in the nuclear reactions. Efficient neutron detection can considerably reduce these effects provided that energy loss through recoil protons dominates. Calorimeters using 238U, Pb or Fe absorbers, and plastic scintillator, liquid-argon, silicon or TMP readout were investigated. Experimental results on e h values and energy resolution, which are often considered confusing, are nicely reproduced and explained.

145 citations


Journal ArticleDOI
TL;DR: In this article, the construction of an adiabatic calorimeter for the temperature range between 10 and 350 K is described, with emphasis given to the construction and regulation of the shields.

91 citations


Journal ArticleDOI
TL;DR: This communication presents a dynamic deconvolution technique directed to remove artificial distortions in the shape of the heat capacity function measured at any scanning rate, and to obtain a kinetic characterization of a thermally induced transition.

77 citations


Journal ArticleDOI
TL;DR: A pyroelectric calorimeter for studies of radiation induced thermal transients in thin films and at surfaces is described in this article, where the signal generation and detection process, as well as design criteria are briefly reviewed.
Abstract: A pyroelectric calorimeter for studies of radiation induced thermal transients in thin films and at surfaces is described. The signal generation and detection process, as well as design criteria are briefly reviewed. Detailed data are presented whereby our design, which has found extensive utility, can be fabricated. This device is compatible with standard Inficon quartz microbalance hardware and provides a sensitivity of several nanojoules at a time resolution of <100 ns over a wide temperature and pressure range.

74 citations


Journal ArticleDOI
TL;DR: In this paper, a simple theory is suggested for the important fire engineering problem of predicting large-scale test fires of surface materials based on information obtained from small-scale tests, and the theory is proved to be correct.
Abstract: A simple theory is suggested for the important fire engineering problem of predicting large-scale test fires of surface materials based on information obtained from small-scale tests.

62 citations


Journal ArticleDOI
TL;DR: In this article, a thermal contact with the sample is made via a grease film and a radiation shield is built into the calorimeter to minimize the effect of temperature gradients.
Abstract: A calorimeter is described in which thermal contact with the sample is made via a grease film. Radiation shields built into the calorimeter minimize the effect of temperature gradients. Used in an adiabatic shield system the apparatus gives results of high precision and accuracy. The new design permits easy sample changing but there is a small specific heat anomaly owing to melting of the grease film. An all‐metal water triple point cell can be installed in place of the sample to check the temperature measuring equipment. The adiabatic shield system used had four independently controlled elements. Experiment showed that a single controlled element is sufficient for discontinuous heating calorimetry. The apparatus could be run in both continuous and discontinuous heating modes. There was no significant difference in results. Measurements on pure copper are reported and the use of this material as a specific heat standard up to 300 K is discussed.

58 citations


Journal ArticleDOI
TL;DR: In this article, a high-pressure adiabatic calorimeter was constructed with using helium gas as a pressure transmitting medium, which works under a constant pressure up to 250 MPa in the temperature range from 12 to 370 K.
Abstract: A novel adiabatic high-pressure calorimeter was constructed with using helium gas as a pressure transmitting medium. It works under a constant pressure up to 250 MPa in the temperature range from 12 to 370 K. Sample cell is made of Be–Cu alloy and has internal volume of 26 cm3. The pressure transmitting tube is connected to an external pressure-control system, which enables to keep automatically the inner pressure constant within ±1 kPa over the whole pressure and temperature ranges. Thus the thermodynamic path that any specimen follows during the heat capacity measurement can be described unambiguously. Heat capacities of the sample cells loaded without and with 158.9 MPa He gas were measured in the temperature range from 25 to 370 K. The imprecision of heat capacity data of the compressed He gas was within 0.3%. Thus the present calorimeter enables us to extend the low-temperature thermodynamic study on various kinds of materials to high pressures without a significant loss of the claimed precision.

48 citations


Patent
16 Apr 1987
TL;DR: In a combustion system, the economic optimum efficiency is achieved by periodically computing a relative index of combustion efficiency using the combustion chamber as a real-time, on-line calorimeter as mentioned in this paper.
Abstract: In a combustion system, the economic optimum efficiency is achieved by periodically computing a relative index of combustion efficiency using the combustion chamber as a real-time, on-line calorimeter. This is accomplished by first determining the combustion chamber inputs and outputs required to calculate a relative index of performance (including measuring the amount of heat released or work performed at the present air/fuel ratio including the stack losses, without oxygen and/or carbon monoxide sensors), sequentially comparing the latest relative index value with the previous value, then adjusting the air/fuel ratio to achieve an improved index value.

48 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a review of the available calorimeter equipment for the measurement of heat effects in chemical and physical processes, and present a new data treatment system for a commercial bench scale isothermal reaction calorometer.

48 citations


Journal ArticleDOI
TL;DR: In this article, the exothermic reaction of the autoxidation of lipids has been studied by isothermal heat flux calorimetry at temperatures between 80°C and 160°C.

38 citations


Journal ArticleDOI
TL;DR: A flux calorimeter for the determination of the thermal properties of solids, useful for the measurement of specific heat, thermal conductivity and pyroelectric coefficient, is described in this paper.
Abstract: A flux calorimeter for the determination of the thermal properties of solids, useful for the measurement of specific heat, thermal conductivity and pyroelectric coefficient, is described. The specific heat of aluminium oxide between 250 and 350 K is determined to show the precision of the measurements. The specific heat and the thermal conductivity of triglycine sulphate are measured near the ferroelectric transition point. From these data, the thermal diffusivity of the sample is calculated. The data agree with those found in the literature.

Journal ArticleDOI
TL;DR: In this article, a 3He+4He dilution refrigerator with three operational modes for measuring heat capacity between 20 mK and 25 K has been constructed, and the accuracy of the calorimeter has been determined indirectly by comparing heat capacities of a common sample with those measured by the 3He-calorimeter whose accuracy has been established on the basis of the 1965 Calorimetry Conference Copper Standard.

Journal ArticleDOI
TL;DR: In this article, the authors measured the heat capacity of liquid Se-Te mixtures using an adiabatic scanning calorimeter and found that the bonding rearrangement is most active in this range of conductivity.
Abstract: The measurements of heat capacity were made for liquid Se–Te mixtures using an adiabatic scanning calorimeter. Liquid Se x Te 1- x mixtures with x =0.2 to 0.6 exhibit maxima in the temperature dependence of heat capacity. The position of heat capacity maximum shifts toward higher temperature with increasing Se concentration. The plots of heat capacity against conductivity show a maximum in the range of 150 to 400 (ohm·cm) -1 . It indicates that the bonding rearrangement is most active in this range of conductivity. A strong correlation is found between the heat capacity and the temperature dependence of magnetic susceptibility. In the semiconducting region, the large excess heat capacity can be attributed to the formation of dangling bonds. In the metallic region, the excess heat capacity can be related to the change in the density of states caused by the bonding rearrangement.

Journal ArticleDOI
TL;DR: In this article, an automated adiabatic calorimeter with an internal volume of 5 cm3, operable over the temperature range from 30 to 380 K, was described.
Abstract: An automated adiabatic calorimeter with an internal volume of 5 cm3, operable over the temperature range from 30 to 380 K is described. One of the main advantages of this calorimeter over others in use is the much abbreviated down time during sample changes, due to interchangeable sample vessels that fit into the heater/thermometer assembly. This calorimeter was tested by measuring the heat capacity of benzoic acid, and the results agreed with the literature values to within 0.5%.

Journal ArticleDOI
TL;DR: The response of the calorimeter to 4-MV x rays has been compared to that of an ionization chamber irradiated in an identical geometry and the zero-power-level calibration curve obtained by extrapolation is employed.
Abstract: A flexible, temperature‐regulated, watercalorimeter has been constructed which consists of three nested cylinders. The innermost ‘‘core’’ is a 10×10 cm right cylinder made of glass, the contents of which are isolated from the environment. It has two Teflon‐washered glass valves for filling, and two thermistors are supported at the center by glass capillary tubes. Surrounding the core is a ‘‘jacket’’ that provides approximately 2 cm of air insulation between the core and the ‘‘shield.’’ The shield surrounds the jacket with a 2.5‐cm layer of temperature‐regulated water flowing at 5 l/min. The core is filled with highly purified water the gas content of which is established prior to filling. Convection currents, which may be induced by dose gradients or thermistor power dissipation, are eliminated by operating the calorimeter at 4 °C. Depending upon the power level of the thermistors, 15–200 μW, and the insulation provided by the glass capillary tubing, the temperature of the thermistors is higher than that of the surrounding water. To minimize potential errors caused by differences between calibration curves obtained at finite power levels, the zero‐power‐level calibration curve obtained by extrapolation is employed. Also the calorimeter response is corrected for the change in power level, and therefore thermistor temperature, that follows the resistance change caused by irradiation. The response of the calorimeter to 4‐MV x rays has been compared to that of an ionization chamber irradiated in an identical geometry. For nitrogen‐saturated water, the grand mean of the calorimeter‐to‐ion chamber (Cal/Ion) dose ratio for five experiments conducted over a period of six months is 1.006±0.001. Three experiments with oxygen‐saturated water in the same core yeild a Cal/Ion ratio of 0.991±0.001. These results are consistent with radiochemical models and refined experiments that used water saturated with various gases, and suggest that nitrogen‐saturated watercalorimeters of the type described may be used to determine the dose‐to‐water without reference to radiation‐dependent parameters or recourse to corrections for thermal defects.

Journal ArticleDOI
P. Sonderegger1
TL;DR: The Omega Inner Calorimeter as mentioned in this paper is a dense electromagnetic calorimeter made of scintillating fibres embedded in grooved Pb sheets or similar configuration, which is entering its third year of successful operation.
Abstract: Dense electromagnetic calorimeters made of scintillating fibres embedded in grooved Pb sheets or similar configuration are described. The Omega Inner Calorimeter is entering its third year of successful operation. Some future prospects are discussed.

Journal ArticleDOI
TL;DR: In this article, the authors compared different design principles for calorimeters with special emphasis on the bench scale isothermal reaction calorimeter which is characterized by: 1 reactor size ⪢ 01 l, 2 active control of the energy transport to or from the reactor fluid in order to keep its temperature constant.

Journal ArticleDOI
TL;DR: In this paper, enthalpy increments of BaMoO 4, BaCeO 3 and (Ba, Sr)ZrO 3 were determined relative to room temperature using a high temperature differential calorimeter.

Journal ArticleDOI
TL;DR: In this paper, the design of the first quasi-adiabatic calorimeter capable of measuring the heat of adsorption of gases on singlecrystal surfaces in ultrahigh vacuum was described.
Abstract: This paper describes the design of the first calorimeter capable of measuring heats of adsorption of gases on single‐crystal surfaces in ultrahigh vacuum. The calorimeter is of the quasi‐adiabatic type, and measures the temperature rise as gas adsorbs. The calorimeter has been used to measure the heat of adsorption of CO and C2H4 on Pt(111). The calorimeter seemed to perform quite well in these experiments, and yielded results that are reasonable. Thus, it is suggested that a calorimeter would be a useful addition to a surface scientist’s arsenal.

Journal ArticleDOI
TL;DR: In this article, a sensitive calorimeter using an isothermal temperature control technique was developed for an accurate measurement of microwatt-level laser power in the visible and infrared spectral region.
Abstract: A sensitive calorimeter using an isothermal temperature control technique was developed for an accurate measurement of microwatt-level laser power in the visible and infrared spectral region. The standard deviation of the measured value on 1-mW-1-μW laser power is 0.06–2 percent corresponding to the level. The systematic error is evaluated to be within ±0.23 percent for the 10 μW level.

Journal ArticleDOI
TL;DR: In this paper, a differential flow heat capacity calorimeter was used to measure the heat capacity of aqueous CaCl 2 at molalities from 0.05 to 3.0 mol · kg −1, temperatures from 306 to 603 K, and a pressure of 17.5 MPa.

Journal ArticleDOI
TL;DR: In this paper, a microcalorimeter is described which was developed and tested for measuring the activity of pure β-particle emitters and two identically made calorimeter cells are used, each 46.5mm i.d. and 54.0mm deep and each fitted with thermomodules of which the outputs are connected in opposing polarities, the net output being amplified and this voltage signal is used to estimate the radioactivity in the samples.

Journal ArticleDOI
TL;DR: In this article, the CHARM fine-grained calorimeter was used for the measurement of the energy and spatial response to both hadronic and electromagnetic showers in π and electron beams from 5 to 140 GeV.
Abstract: Calorimeters have been used extensively for the study of neutrino interactions in the last decade. This paper describes the need for calibration of such calorimeters and how this was realized for the case of the CHARM fine-grained calorimeter. The energy and spatial response of the calorimeter to both hadronic and electromagnetic showers was measured in π and electron beams from 5 to 140 GeV. The results and resolutions are presented.

Journal ArticleDOI
TL;DR: A simple portable calorimeter was constructed by embedding a calibrated thermistor on the axis of a polystyrene rod, embedded in a cylindrical array of 60 Co rods, in good agreement with earlier measurements made with a graphite calorimeters.
Abstract: A simple portable calorimeter was constructed by embedding a calibrated thermistor on the axis of a polystyrene rod. This instrument was positioned on the axis of a cylindrical array of 60 Co rods. The duration of the measurements was ∼ 70 s. Absorbed dose rates of ∼ 70 Gy/min were measured to a daily precision of several tenths of a percent standard deviation. The results are in good agreement with earlier measurements made with a graphite calorimeter. An absorbed dose of 620 kGy resulted in no detectable change is thermistor sensitivity. The specific heat capacity of the polystyrene presumably increased ∼ 0.0024%/kGy. The use of a chart recorder was not necessary.

Journal ArticleDOI
TL;DR: An experimental set-up for measuring enthalpies of solution of gases in liquids is described in this article, which consists of a vacuum line for gas handling and a Tian-Calvet microcalorimeter.

Journal ArticleDOI
TL;DR: In this paper, a complete calorimetric run of a thermally induced martensitic transformation is described and analyzed in detail by means of a simple model of heat transfer in the calorimeter.

Journal ArticleDOI
TL;DR: In this paper, a low noise electronic amplification chain was designed for the readout of the one-stage vacuum photomultipiers (phototriodes) of the DELPHI lead-glass calorimeter.
Abstract: In this paper we describe the low noise electronic amplification chain designed for the readout of the one-stage vacuum photomultipiers (phototriodes) of the DELPHI lead-glass calorimeter. A mean open input electronic noise of 166 e − rms has been obtained with unipolar shaping. For completely mounted phototriodes in a situation very close to the final experimental setup and bipolar shaping we get a mean noise of 292 e − rms. Very good immunity against acoustic noise has been obtained. The gain stability during six months of operation is better than ±0.3%.

Journal ArticleDOI
TL;DR: A large-scale electromagnetic calorimeter comprising 4300 lead glass Cherenkov counters has been constructed for the TOPAZ detector at the TRISTAN e+e-collider as discussed by the authors.
Abstract: A large-scale electromagnetic calorimeter comprising 4300 lead glass Cherenkov counters has been constructed for the TOPAZ detector at the TRISTAN e+e- collider. Various beam tests have been performed to study the basic properties. The data were compared with simulated data based on the EGS4 code. In this report, the results of beam tests and a comparison to simulated data are described.

Journal ArticleDOI
TL;DR: In this paper, a computer program for the determination of heats of solution and reaction in a constant-environment calorimeter has been developed, with particular attention paid to the choice of parameters such as K / C and the endpoint of a generic calorimetric reaction in solution.

Journal ArticleDOI
TL;DR: In this paper, a high-temperature enthalpy-of-dilution flow calorimeter was used for the measurement of relative heat capacities of enthalpies of dilution.