A Coaxial Calorimeter for Use as a Microwave Power Standard

A coaxial calorimeter has been built for use in the comparison of power at high frequencies with dc resistance and voltage standards. The temperature rise of the metal jacket of a 50-ohm coaxial termination is measured with a thermopile when a known level of dc power is fed into the calorimeter. The high-frequency sensitivity of the calorimeter is obtained by modifying the dc sensitivity for: 1) Input VSWR of the calorimeter, 2) Attenuation of a 6-inch length of thermally insulating input coaxial line, 3) The effect of current distribution in the load. The accuracy is estimated at better than ±1 per cent below 4 Gc/s with the largest errors due to the input VSWR of the calorimeter.     

A simple model of hadron calorimeters

A simple model of hadron calorimeter response is examined. It is found that not only must a hadron calorimeter be compensated in order to achieve linearity, but also that the intrinsic hadron and electromagnetic resolutions must be equal if the calorimeter resolution is to be independent of energy and have a Gaussian distribution.     

高精密自动绝热量热计

介绍了中国计量科学研究院用新近开发的高精密自动绝热量热计的测量控制系统对美国国家标准技术研究院（NIST）的标准物质α-Al2O3进行的比热测量,并对测量结果和不确定度作了分析。该自动绝热量热计是中国计量科学研究院原有的绝热量热计的发展,它继承了原有量热计的本体,又开发了高精度量热和温度自动测量控制系统。进行了与NIST的数据和其它数据对比以及不确定度分析。测量结果与NIST的数据相比,其相对均方根偏差为0．447％,一致性为0．167％。合成相对标准不确定度为0．333％。结果表明,该自动绝热量热计具有高精密量热和比热测量的能力。     

Development of a High-Precision Calorimeter for Measuring Power Loss in Electrical Machines

This paper is concerned with the development of a high-precision 30-kW (40-hp) calorimeter and is specifically focused on how experimental errors resulting from calorimeter design and operating procedures are eliminated or mitigated. A complete calibration for the calorimetric system using a dc heater is conducted, and two induction motors rated at 5.5 and 30 kW (7 and 40 hp, respectively) are carefully tested both within and outside of the calorimeter. Loss segregation is in accordance with the IEEE 112 method B. Experimental results for the comparison of calorimetric and input–output methods clearly confirm the effectiveness of the calorimeter in terms of accurate power loss measurement. The accuracy of the calorimeter is approximately 5.6 W in the measurement of power loss of up to 4.5 kW with a resolution of 0.1 W.      

Thermal conductivity of subcooled liquid oxygen

The thermal conductivity of liquid oxygen below 80 K and pressures up to 1 MPa has been measured using a horizontal, guarded, flat-plate calorimeter. The working equation of the calorimeter is based on the one-dimensional Fourier’s law. The gap between the calorimeter plates was measured in situ from a capacitance measurement. The cooling power to the calorimeter is provided by a two-stage Gifford-McMahan cryocooler. The absolute temperatures are measured using platinum resistance thermometers. The results are compared to existing data and analytical models.     

The CDF plug upgrade electromagnetic calorimeter: test beam results

The CDF Plug Upgrade calorimeter, which fully exploits the tile–fiber technique, was tested at the Fermilab meson beamline. The calorimeter was exposed to positron, positively charged pion and positive muon beams with energies in the range of 5–230 GeV. The energy resolution of the electromagnetic calorimeter to the positron beam is consistent with the design value of , where E is the energy in units of GeV and represents sum in quadrature. The non-linearity for positrons is studied in an energy range of 11–181 GeV. It is important to incorporate the response of the preshower detector, the first layer of the electromagnetic calorimeter which is readout separately, into that of the calorimeter to reduce the non-linearity to 1% or less. The energy scale is about 1.46 pC/GeV with HAMAMATSU R4125 operated typically at a gain of 2.5×10⁴. The response non-uniformity over the surface of a tower of the electromagnetic calorimeter is found to be about 2% with 57 GeV positrons. Studies of several detailed detector characteristics are also presented.     

Test of a prototype of the ZEUS backing calorimeter

We have studied the performance of a high resolution uranium-scintillator calorimeter followed by a much coarser backing calorimeter, made out of iron plates interleaved with planes of limited streamer tubes. The test results, obtained at the CERN-SPS hadron beam, show that the backing calorimeter can be used either to veto events with significant energy leakage from the uranium calorimeter or to correct for the energy. In both cases the energy resolution of the combined calorimeters improves significantly compared to the uranium calorimeter alone.     

The performance of a uranium gas sampling calorimeter

The performance of a uranium gas sampling hadron calorimeter is described. It has been observed that the hydrogen content of the gas mixture plays an important role in defining the behaviour of this type of calorimeter. The low-energy neutrons emerging from a hadron cascade are detected much more efficiently in a hydrogenous gas; thus leakage or containment of these neutrons becomes an important feature of the calorimeter setup.     

Simulations of a thin sampling calorimeter with GEANT/FLUKA

The Advanced Cosmic-ray Composition Experiment for the Space Station (ACCESS) will investigate the origin, composition and acceleration mechanism of cosmic rays by measuring the elemental composition of the cosmic rays up to 10¹⁵ eV. These measurements will be made with a thin ionization calorimeter and a transition radiation detector. This paper reports studies of a thin sampling calorimeter concept for the ACCESS thin ionization calorimeter. For the past year, a Monte Carlo simulation study of a thin sampling calorimeter (TSC) design has been conducted to predict the detector performance and to design the system for achieving the ACCESS scientific objectives. Simulation results show that the detector energy resolution function resembles a Gaussian distribution and the energy resolution of TSC is about 40%. In addition, simulations of the detector's response to an assumed broken power law cosmic ray spectrum in the region where the ‘knee’ of the cosmic ray spectrum is believed to occur have been conducted and clearly show that a thin sampling calorimeter can provide sufficiently accurate estimates of the spectral parameters to meet the science requirements of ACCESS.     

Calorimetric Measurement of Pulsed Laser Output Energy

There are several methods by which one may measure the energy output of the pulsed laser. However, the technique which seems to be most promising as far as accuracy and precision are concerned is the calorimetric method. We have designed, built, and calibrated calorimeters for measuring the output energy of the pulsed ruby laser (6943?). The heart of the calorimeter is a small absorption cell containing an aqueous solution of CuSO4. The temperature of the absorption cell, as measured by a thermocouple, indicates the energy absorbed by the calorimeter. The calorimeter was calibrated in two different ways: 1) the known heat capacity of the absorption cell and the thermocouple sensitivity calibration gives a calorimeter calibration, which agrees within 0.3 percent of 2) an electrical energy substitution calibration which is obtained via a heater wire contained in the absorption cell solution. A method has been devised by which two calorimeters may be intercompared. Calorimeters which we have built and calibrated agree with each other to about 0.7 percent. This specific calorimeter has been designed to measure energies up to 30 J and will take peak powers of up to 200 MW/cm2.     

Measurement of the Calorific Value of Methane by Calorimetry Using Metal Burner

With the diversification of natural gas origins and variations in natural gas compositions, the accurate measurement of the calorific value of natural gas has become a very important issue for the gas industry and standardization. Korea Research Institute of Standards and Science is developing a standard gas calorimeter based on the isoperibolic technique. This work describes the details of the experimental apparatus and procedures of the developed gas calorimeter along with the measurement results for the superior calorific value of methane at \(25\,^{\circ }\hbox {C}\). A burner made of stainless steel was used for the first time in this type of calorimeter, and the potential application of a metal burner to a gas calorimeter was investigated. Eight measurements were performed, and the deviation from international standards was 0.16 %. The deviation was mainly caused by the measurement of the burned methane gas. The measurement results show that the metal burner may potentially be employed in a gas calorimeter.     

Investigations of the characteristics of the DELPHI hadron calorimeter prototype

The characteristics of the DELPHI hadron calorimeter prototype in various modes of operation of its detectors are presented in this paper. It is shown that the transition to a saturated proportional mode and the use of more sensitive electronics do not worsen the hadron calorimeter operation. The possibility to select muon tracks in the hadron calorimeter and to use them for detector triggering has been investigated. The results of nuclear shower simulation in the detector are presented.     

3D-modelling of temperature gradients induced by electrical power dissipation in a 3-body Domen-type calorimeter for absorbed dose measurements

The effect of thermal gradients that appear in the core of a Domen-type absorbed-dose calorimeter during an electrical calibration run is revised using a finite element 3D-numerical analysis. The local thermal modelling, that is the method allowing for spatio-temporal distribution of temperature within the three bodies of the graphite calorimeter, combined with both a careful analysis on what really happens when a certain amount of electrical power is dissipated in a NTC heating thermistor and the consideration of heat loss through radiation from the surface of the calorimeter bodies, has led to results which are in agreement with those obtained from experimental measurements and reported in the literature.     

A tower structured scintillator-lead photon calorimeter using a novel fiber optics readout system

Described is the construction and the performance of a tower-structured scintillator-lead photon calorimeter using a novel fiber optics readout system. The calorimeter is divided into 9 individual towers. Each tower has a cross section of 5 × 5 cm² and consists of 60 layers of 2 mm lead plus 5 mm thick scintillator. The four sides of each tower are covered by thin acrylic sheets (1.5 mm thick) doped with a wavelength shifting material. The light produced in each scintillator plate is first converted in these sheets, then converted a second time in a set of polystyrene optical fibers (diameter 2 mm) which run longitudinally through the calorimeter along the corners of each tower. A small diameter photomultiplier was attached to the fibers at the back end of the calorimeter. The obtained energy resolution with incident electrons in the range of is . The uniformity of response across the front face of each tower was measured.     

Capabilities of a magnetic adiabatic calorimeter in measurement technology

The design of a magnetic calorimeter for the measurement of releases of energy that correspond to a number of rare events, for example, cosmic particles, particles of dark matter, isolated x-ray quanta, and so on, is proposed. The calorimeter is set into a working state by means of the method of adiabatic demagnetization and the response to energy release is measured by a quantum interferometer (squid). The action of the calorimeter in different practical problems is considered, and the sensitivity of the device and its measurement precision are estimated. Translated from Izmeritel'naya Tekhnika, No. 11, pp. 24–30, November, 2008.     

A simple continuous-flow calorimeter for measuring the specif heat of gases

A bridge-type arrangement of a capillary continuous-flow calorimeter for measurement of the specific heat of gases at constant pressure is described. The method of the experiment is analyzed. The construction of the calorimeter and the results of tests of its operation are described.     

A 5 in. Si(Li)/Pb sampling calorimeter telescope for observation of cosmic gamma rays in the GeV region

A 5 in. diameter Si(Li)/Pb sampling calorimeter with a depth of 28 radiation lengths (30 unit cells × 0.93 radiation lengths) has been constructed. The energy and angular resolutions of the calorimeter have been investigated using CERN SPS positron beams with energies of 10 to 147.8 GeV. The calorimeter shows good linearity over this energy region and the energy resolution is expressed well by σ_E (rms)/E = (16.9 ± 0.9)%/ √E[GeV], where E represents the incident beam energy. The angular resolution of the calorimeter for a single event is 0.3° (rms) at 80 GeV/c. The agreement between these results and Monte Carlo simulations is good.

We are showing a new design of the Si(Li)/Pb sampling calorimeter telescope (SSCT) with an angular resolution (point source localization capability) of about 0.04° (rms) for bright galactic gamma-ray sources. We believe that this telescope is a suitable detector for future observations of cosmic gamma rays in the GeV region, especially when used to search for point sources.     

Thermal state of dynamic calorimeters

It is established here how the thermal state of a calorimeter affects the accuracy of power measurements. A mathematical model of a dynamic calorimeter is proposed and its thermal state is analyzed.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 26, No. 3, pp. 403–410, March, 1974.     

On quality requirements to the barium fluoride crystals

This report summarizes the quality requirements to the barium fluoride (BaF₂) crystals for constructing a high precision electromagnetic calorimeter at future hadron colliders. The basic property of BaF₂ crystals and the design and performance of a BaF₂ calorimeter are presented. The emphasis of the discussion is in the radiation resistance of the current production BaF₂ crystals. An approach to implement optical bleaching in situ is also presented. By using optical bleaching current production quality BaF₂ crystals could serve as an excellent candidate to construct a precision calorimeter at future hadron colliders.     

应用锥形量热法评价聚合物复合材料热释放速率

研究了应用锥形量热法测量聚合物复合材料燃烧的热释放速率时,填料的分解热效应对测量结果的影响。定量研究表明,对于氢氧化铝和氢氧化镁等阻燃填料,当填料的质量分数超过60%时,填料分解时强烈吸热的特性对于应用锥形量热法测量聚合物基复合材料的热释放速率有明显影响,并且还因聚合物而异。在定量研究的基础上,提出了一种利用分解焓对锥形量热仪测定的有效燃烧热值进行校正,然后再换算成热释放速率的简单方法,并给出了校正后的结果同实测值的比较。