Temperature measurement of warm-dense-matter generated by intense heavy-ion beams

Ni, P.; Kulish, Mariano; Минцев, В. Б.; Nikolaev, D. N.; Ternovoǐ, V. Ya.; Hoffmann, D. H. H.; Udrea, S.; Hug, Alexander; Tahir, N. A.; Varentsov, D.

doi:10.1017/s0263034608000645

Cited by 32 publications

(20 citation statements)

References 29 publications

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“…Both Newton-Gauss and Levenberg-Marquardt, algorithms commonly used least-square optimization algorithms (Ni et al 2008;), lead to the same results. The 2400 K fit is in much better agreement with the thermodynamic analysis but is not such a nice fit to the measured spectrum from a statistical point of view.…”

Section: Real-world Example Of "Blind" Curve Fittingmentioning

confidence: 79%

“…The fundamental reason for this is the fact the high-frequency (optical) AC conductivity, or equivalently the optical constants n, k, which determine the emissivity, are not known for material at WDM conditions. An attempt to improve the situation by simultaneously measuring emission at many wavelengths (multi-wavelength pyrometery) (Dewitt, 1998;Ni et al 2008;Ni et al 2011) does not solve the problem because there is a new unknown emissivity E(λ) at each new wavelength λ and there always N+1 unknowns, where N is the number of direct measurements. Thus from the mathematical point of view, multi-wavelength pyrometry cannot produce a unique temperature.…”

Section: Introductionmentioning

confidence: 99%

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Reliability of temperature determination from curve-fitting in multi-wavelength pyrometery

Bieniosek

2013

Laser Part. Beams

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This paper examines the reliability of a widely used method for temperature determination by multi-wavelength pyrometry. In recent WDM experiments with ionbeam heated metal foils, we found that the statistical quality of the fit to the measured data is not necessarily a measure of the accuracy of the inferred temperature. We found a specific example where a second-best fit leads to a more realistic temperature value. The physics issue is the wavelength-dependent emissivity of the hot surface. We discuss improvements of the multi-frequency pyrometry technique, which will give a more reliable determination of the temperature from emission data.Keywords: warm dense matter, temperature measurement, pyrometry, heavy ion beam heating. IntroductionWarm dense matter can be produced by several heating technologies including lasers, pulsed electric current, electron, ion and x-ray beam heating, shock-wave heating, etc (DOE, 2009;Hoffmann et al. 2005;Sasaki et al. 2006;Ng et al. 2005; Lee et al. 1998). Temperature measurements are essential to WDM science. In most cases the deposited energy is determined accurately but at present there is no universal method to directly measure the temperature. As a consequence, the specific heat C = dE/dT is not accurately determined and this is a key unknown aspect of the equation of state (EOS). There is also a class of experiments, which aims to study phase transitions: these may be high-temperature evaporation of refractory metals, a liquid-vapor critical point, or an abrupt change of electronic structure (metal-insulator transition). Such transitions typically occur at definite temperatures and an accurate measurement of the transition temperature is obviously a key step for building up the quantitative science of warm dense matter. Today the critical points of refractory metals are uncertain to something like 50 % and this uncertainty is a leading source of EOS uncertainty for WDM expanded below solid density. At higher energy-density (HEDP), shock Hugoniot measurements can accurately determine for the material density, energy-density and pressure, but different EOS models predict different temperatures for the same (energy/pressure/density) shocked conditions, so again temperature is a key uncertainty for HEDP EOS data. Finally, almost all the computer codes used to predict the properties of warm dense matter (or hotter plasmas) use density and temperature as inputs and for this reason it will be easier to directly compare theory and experiment if one can accurately measure the temperatures attained in any given experiment.

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Section: Real-world Example Of "Blind" Curve Fittingmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Reliability of temperature determination from curve-fitting in multi-wavelength pyrometery

Bieniosek

2013

Laser Part. Beams

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“…It is difficult to create uniform, well defined WDM state and then precisely characterize it. The experimental uncertainty in the emissivity of WDM is relatively large [13]. Therefore, the computational prediction of the emission spectra of WDM is important compared to performing experiments.…”

Section: Introductionmentioning

confidence: 99%

Atomic and optical properties of warm dense copper

Miloshevsky

Hassanein

2015

Phys. Rev. E

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The emission of X-rays from warm dense matter is of great interest for both spectroscopic diagnostics and development of intense X-ray sources. We report the results from the collisionalradiative steady state (CRSS) modeling of atomic and optical properties of copper plasmas at near-solid and solid-state density for a range of temperatures. The CRSS model is validated against the available data on the average charge state and shifts of energy levels in aluminum and the opacity and emissivity spectra of carbon and aluminum plasmas. The average charge states, number density of ion species, and free electrons as a function of temperature are investigated for the solid-density copper plasma. Due to dense plasma environment the four outer electrons are found to be unbounded even in the low-temperature limit ~1 eV. As the temperature changes from 1 eV to 100 eV, the predominant species vary from five-fold to twelve-fold ionized copper ions. The opacity and emissivity spectra of dense copper plasmas are studied using the local thermodynamic equilibrium (LTE) and non-LTE approaches. It is found that the non-LTE effects are important in the spectral region of soft X-rays emitted from the K-shell. The emissivity in spectral lines is completely suppressed indicating the importance of the energy-dissipating radiative processes in this soft X-ray region. The line broadening and red shifts of the K-shell 2 and L-shell spectral lines toward higher wavelengths are observed with the increase of plasma density. These results have important implications for understanding the radiative properties of warm dense copper and can be useful for future experimental studies. * gennady@purdue.edu 3

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“…This shows that a substantial progress in the technology of high intensity bunched beams is required to achieve ion beam ICF. However, theoretical work that includes sophisticated two-and three-dimensional numerical simulations as well as analytic modeling [15][16][17][18][19][20][21][22][23][24][25][26][27][28] has shown that one can carry out very useful work in the field of high energy density ͑HED͒ physics using the existing ion beam facilities and those which will be available in the foreseeable future.…”

Section: Introductionmentioning

confidence: 99%

Generation of warm dense matter and strongly coupled plasmas using the High Radiation on Materials facility at the CERN Super Proton Synchrotron

et al. 2009

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A dedicated facility named High Radiation on Materials ͑HiRadMat͒ is being constructed at CERN to study the interaction of the 450 GeV protons generated by the Super Proton Synchrotron ͑SPS͒ with fixed solid targets of different materials. The main purpose of these future experiments is to study the generation and propagation of thermal shock waves in the target in order to assess the damage caused to the equipment, including collimators and absorbers, in case of an accident involving an uncontrolled release of the entire beam at a given point. Detailed numerical simulations of the beam-target interaction of several cases of interest have been carried out. In this paper we present simulations of the thermodynamic and the hydrodynamic response of a solid tungsten cylindrical target that is facially irradiated with the SPS beam with nominal parameters. These calculations have been carried out in two steps. First, the energy loss of the protons is calculated in the solid target using the FLUKA Nucl. Sci. Eng. 123, 169 ͑1996͔͒, which is based on a Godunov-type numerical scheme. The transverse intensity distribution in the beam focal spot is Gaussian. We consider three different sizes of the focal spot that are characterized by standard deviations, = 0.088, 0.28, and 0.88 mm, respectively. This study has shown that the target is severely damaged in all the three cases and the material in the beam-heated region is transformed into warm dense matter including a strongly coupled plasma state. This new experimental facility can therefore also be used for dedicated experiments to study high energy density matter.

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Temperature measurement of warm-dense-matter generated by intense heavy-ion beams

Cited by 32 publications

References 29 publications

Reliability of temperature determination from curve-fitting in multi-wavelength pyrometery

Reliability of temperature determination from curve-fitting in multi-wavelength pyrometery

Atomic and optical properties of warm dense copper

Generation of warm dense matter and strongly coupled plasmas using the High Radiation on Materials facility at the CERN Super Proton Synchrotron

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