Simple numerical modelling technique for cryostat design

Caplin, A.D.; Cayless, A.T.

doi:10.1016/0011-2275(86)90168-2

Cited by 15 publications

(11 citation statements)

References 3 publications

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“…3 for simplicity) placed inside the neck of the cryostat has enough ba es to cut any convection of the He gas and smooth out any horizontal temperature gradient. Therefore, we can expect that 23,25 :…”

Section: Thermodynamic Model For Compact Cryostat Designmentioning

confidence: 99%

“…Here, for simplicity we don't consider the latent heat of evaporation of He because it is small enough to be neglected 23 .…”

Section: Thermodynamic Model For Compact Cryostat Designmentioning

confidence: 99%

“…In this paper, inspired by the work from Caplin et al 23 , we report an easy to implement numerical technique that helped us to assess the feasibility and to optimize the design of a non-conventional compact liquid He cryostat equipped with an intrinsically high thermal conductivity probe for the insertion, storage and NMR measurement of HP samples. We provide all details about the materials and construction of the cryostat, we analyse in depth the cryogenic performance, and we use NMR to characterize the magnetic eld behaviour as a function of time and temperature of the storage magnet.…”

Section: Introductionmentioning

confidence: 99%

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Design and performance of a small bath cryostat with NMR capability for transport of hyperpolarized samples

Capozzi

2022

Preprint

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As of today, dissolution Dynamic Nuclear Polarization (dDNP) is the only clinically available hyperpolarization technique for 13C-MRI. Despite the clear path towards personalized medicine that dDNP is paving as an alternative and/or complement to Positron Emission Tomography (PET), the technique struggles to enter everyday clinical practice. Because of the minute-long hyperpolarization lifetime after dissolution, one of the reasons lies in the need and consequent complicacies of having the machine that generates the hyperpolarization (i.e. the dDNP polarizer) on site. Since some years, research groups are working to make hyperpolarization transportable. Two different methods have been developed that allow “freezing” of the nuclear spin state prior to samples extraction from the polarizer. Nevertheless, so far, all attempts of transport have been limited to a very small scale and to the level of proof-of-principle experiments. The main reason for that is the lack of adequate hardware, strategy, and control on most of the crucial parameters. To bridge the technical gap with PET and provide MRI facilities with hours long relaxing hyperpolarized compounds at controlled conditions, a new generation of low cost/small footprint liquid He cryostats equipped with a magnetically enforced cryogenic probe is needed. In this paper, we detail the theoretical and practical construction of a hyperpolarized samples transportation device small enough to fit in a car and able to hold a sample at 4.2 K for almost 8 h despite the presence of a cryogenically-demanding purpose-built probe that provides enough magnetic field upon insertion of the sample and NMR quality homogeneity at storage position. Should transportable hyperpolarization via DNP become a reality, we herein provide important details to make it possible.

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Section: Thermodynamic Model For Compact Cryostat Designmentioning

confidence: 99%

“…Here, for simplicity we don't consider the latent heat of evaporation of He because it is small enough to be neglected 23 .…”

Section: Thermodynamic Model For Compact Cryostat Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design and performance of a small bath cryostat with NMR capability for transport of hyperpolarized samples

Capozzi

2022

Preprint

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“…Numerical and experimental investigations of heat in-leak into cryostats, Dewars and super-insulation (SI) have been performed by many authors [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Optimum design of liquid helium dewar with vapour cooled shields

Syed¹,

Goyal²,

Atrey³

2016

Indi. Jour. of Cryog.

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The work presented aims to develop a numerical model which can be used to design a vapour shielded liquid helium (LHe) Dewar without LN2 Shield. This model can compute the position of shields and the Net Evaporation Rate (NER) based on the capacity and number of vapour cooled shields (VCS) given by the user. The effect of neck dimensions on the heat in-leak is also given by this model. Heat in-leak design calculations are done using Finite Difference Method (FDM). A computer program is developed using MATLAB®. The results can be obtained either in graphical form or in terms of minimum NER and optimal positions of the VCS. The model is validated against available results in literature and additional results are discussed in detail. This program can be extended to estimate the neck dimensions and position of shields for any given capacity, number of shields and allowable boil-off rate.

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“…This tank was later improved by Dewar [22] to store hydrogen liquid at 20.4 K. Several experimental studies were carried out by the researchers [23][24][25][26][27] to investigate the heat transfer in cryostat from ambient. Shu et al [28] recommended for an optimal insulation of a nitrogen cryostat with a number of screen layers.…”

mentioning

confidence: 99%