Calorimeter cryogenic

Reviews of batch calorimeters for a variety of applications are published in the volume on Solution Calorimetry [8] cryogenic conditions by Zollweg [22], high temperature molten metals and alloys by Colinet andPasturel [19], enthalpies of reaction of inorganic substances by Cordfunke and Ouweltjes [16], electrolyte... 

Equation (4.2) can be used to determine the entropy of a substance. A pure crystalline sample is placed in a cryogenic calorimeter and cooled to low temperatures. Increments of heat, q, are added and the temperature change, AT, is measured, from which the heat capacity can be calculated from the relationship... 

Extrapolations are always subject to error, but fortunately the contribution to the entropy resulting from the extrapolation is a small part of the total. In glucose, for example, S g = 219.2 0.4 J-K -moF1, but the entropy contribution at 10 K obtained from the Debye extrapolation is only 0.28 J-K 1-mol 1. Well-designed cryogenic calorimeters are able to produce Cp measurements of high accuracy hence, the Third Law entropy obtained from the Cp measurements can also be of high accuracy. 

A cryogenic calorimeter measures Cp,m as a function of temperature. We have seen that with the aid of the Third Law, the Cp,m data (along with AHm for phase changes) can be integrated to give the absolute entropy... 

Cryogenic detectors (calorimeters) were proposed in the 1980s by Fiorini and Niinikoski for searching rare events like neutrinoless double-beta decay ( 3 3-Ov) [52],... 

The physical process occurring in a low-temperature calorimeter as particle detectors are fully described in ref. [55,56], In the next sections, we will focus on the cryogenic aspect of a detector, examining the type of detector used in CUORICINO experiment (see Section 16.6). 

The astronomical calorimeters for the detection of the infrared radiation (usually called bolometers) do not conceptually differ from the cryogenic detectors used in nuclear physics as those just described for CUORICINO. 

Massive cryogenic calorimeters are considered of great importance in experiments of neutrinoless DBD. In particular, they can investigate about several nuclei candidate for DBD, taking advantage from the fact that the detector may be rich in nuclei under study. 

To avoid the necessity of a cryogenic container, some calorimeters have utilized molecular liquids like TMS [188] and 2,2,4,4-tetramethylpentane [189]. 

An adiabatic low-temperature c orimeter designed specifrcally for a vapor-deposited sample is depicted in Fig. 1. This calorimeter equips with a built-in cryorefrigerator which enables to keep the calorimetric cell at cryogenic temperatures for a long time. 

A gH value was evaluated cryogenically from the lowering of melting point in the systems LiH-LiOgO and LiH-CaHg. The second value was derived from enthalpy data measured with copper block calorimeter. The adopted enthalpy data of Vogt (j ) using the adopted heat capacities for LiH(cr) and LiH(t). 

The cryogenic calorimeter which has been in operation at the U.S. Geological Survey for many years has been described by Robie and Hemingway (1972). 

A NEW STEADY-STATE CALORIMETER FOR MEASURING HEAT TRANSFER THROUGH CRYOGENIC INSULATION... 

A New Steady-State Calorimeter for Measuring Heat Transfer Through Cryogenic Insulation 65... 

Any calorimeter designed for cryogenic work is subject to thermal contraction of one or both of the insulation boundary surfaces. For the calorimeter at hand, the geometric modification due to thermal expansion and contraction was calculated using data of Corruc-cini and Gniewek [ ]. Calculations show that an error as high as 4.6% can be introduced into the results unless the expansion and contraction phenomena are taken into account in evaluation of the data [ ]. 

D. R. Beck, A Steady-State Calorimeter for Measuring the Heat Transport through Cryogenic Insulations, M.S. Thesis in Mechanical Engineering, University of Colorado (1962),... 

Figure 5.5 A cryogenic or low-temperature calorimeter. The sample container can be raised by the rotary winch so as to be in contact with the liquid helium reservoir for cooling to 4.2 K, or lowered into the vacuum for heating. The re-entrant well in the sample container contains a heating coil. (Simplified from Robie and Hemingway, 1972.)...

Gmelin (1967) described a construction with the sample inside a vacuum-tight thermostatized copper can positioned in a second container that was immersed in the cryogenic liquid in a proper Dewar vessel (Figure 7.30). He used this calorimeter to measure the heat capacity of different oxides between 1.2 and 70 K. 

---