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Response of wavelength-shifting and scintillating-wavelength-shifting fibers to ionizing radiation
Authors:
W. Bae,
J. Cesar,
K. Chen,
J. Cho,
D. Du,
J. Edgar,
W. Earthman,
O. M. Falana,
M. Gajda,
C. Hurlbut,
M. Jackson,
K. Lang,
C. Lee,
J. Y. Lee,
E. Liang,
J. Liu,
C. Maxwell,
C. Murthy,
D. Myers,
S. Nguyen,
D. Phan,
T. O'Brien,
M. Proga,
S. Syed,
M. Zalikha
, et al. (1 additional authors not shown)
Abstract:
We report results of characterizing the response and light transport of wavelength-shifting (WLS) and scintillating-wavelength-shifting (Sci-WLS) fibers under irradiation by radioactive $α$, $β$, and $γ$ sources. Light yield and light transmission were measured for the WLS fiber BCF-91A from Saint-Gobain and for a new Sci-WLS fiber EJ-160 from Eljen Technology.
The two variants with different fl…
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We report results of characterizing the response and light transport of wavelength-shifting (WLS) and scintillating-wavelength-shifting (Sci-WLS) fibers under irradiation by radioactive $α$, $β$, and $γ$ sources. Light yield and light transmission were measured for the WLS fiber BCF-91A from Saint-Gobain and for a new Sci-WLS fiber EJ-160 from Eljen Technology.
The two variants with different fluor mixtures, EJ-160I and EJ-160II, exhibited approximately five and seven times higher light yield than BCF-91A, respectively, while their attenuation lengths were 3.80\,m for BCF-91A, 4.00\,m for EJ-160I, and 2.50\,m for EJ-160II.
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Submitted 15 March, 2026; v1 submitted 26 September, 2025;
originally announced October 2025.
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Optical characterization of wavelength-shifting and scintillating-wavelength-shifting fibers
Authors:
W. Bae,
J. Cesar,
K. Chen,
J. Cho,
D. Du,
J. Edgar,
L. Earthman,
O. M. Falana,
M. Gajda,
C. Hurlbut,
M. Jackson,
K. Lang,
C. Lee,
J. Y. Lee,
E. Liang,
J. Liu,
C. Maxwell,
C. Murthy,
D. Myers,
S. Nguyen,
T. O'Brien,
M. Proga,
T. Rodriguez,
S. Syed,
M. Zalikha
, et al. (1 additional authors not shown)
Abstract:
We report results of optical characterizations of new wavelength-shifting and scintillating-wavelength-shifting fibers EJ-182 and EJ-160 from Eljen Technology and compare them to the wavelength-shifting fiber BCF-91A from Saint-Gobain. The wavelength-dependence of attenuation was derived from spectral measurements confirming that the long attenuation length increases with wavelength, while short a…
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We report results of optical characterizations of new wavelength-shifting and scintillating-wavelength-shifting fibers EJ-182 and EJ-160 from Eljen Technology and compare them to the wavelength-shifting fiber BCF-91A from Saint-Gobain. The wavelength-dependence of attenuation was derived from spectral measurements confirming that the long attenuation length increases with wavelength, while short attenuation effects become less significant at longer wavelengths. The impact of the environmental refractive index was studied by immersing the EJ-160II fiber in water. Immersing the fiber in water reduced the overall light output and suppressed the short attenuation component, which can be explained by reduced light-collection efficiency due to the smaller refractive-index contrast between the fiber cladding and the surrounding medium.
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Submitted 20 December, 2025; v1 submitted 22 September, 2025;
originally announced September 2025.
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Pauli crystals in harmonic trap and on a sphere
Authors:
Filip Gampel,
Mariusz Gajda,
Magdalena Załuska-Kotur,
Jan Mostowski
Abstract:
Recently predicted and observed Pauli crystals are structures formed by trapped ultracold non-interacting particles obeying Fermi statistics. The relative positions of the particles are determined by the trapping potential and the Pauli exclusion principle. Measuring all particles at once, their positions tend to be close to vertices of non-trivial polyhedrons. Similar shapes are found for systems…
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Recently predicted and observed Pauli crystals are structures formed by trapped ultracold non-interacting particles obeying Fermi statistics. The relative positions of the particles are determined by the trapping potential and the Pauli exclusion principle. Measuring all particles at once, their positions tend to be close to vertices of non-trivial polyhedrons. Similar shapes are found for systems of particles bound to the surface of a sphere.
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Submitted 28 May, 2021;
originally announced May 2021.
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Single shot imaging of trapped Fermi gas
Authors:
Mariusz Gajda,
Jan Mostowski,
Tomasz Sowiński,
Magdalena Załuska-Kotur
Abstract:
Recently developed techniques allow for simultaneous measurements of the positions of all ultra cold atoms in a trap with high resolution. Each such single shot experiment detects one element of the quantum ensemble formed by the cloud of atoms. Repeated single shot measurements can be used to determine all correlations between particle positions as opposed to standard measurements that determine…
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Recently developed techniques allow for simultaneous measurements of the positions of all ultra cold atoms in a trap with high resolution. Each such single shot experiment detects one element of the quantum ensemble formed by the cloud of atoms. Repeated single shot measurements can be used to determine all correlations between particle positions as opposed to standard measurements that determine particle density or two-particle correlations only. In this paper we discuss the possible outcomes of such single shot measurements in case of cloud of ultra-cold non-interacting Fermi atoms. We show that the Pauli exclusion principle alone leads to correlations between particle positions that originate from unexpected spatial structures formed by the atoms.
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Submitted 31 August, 2016; v1 submitted 3 November, 2015;
originally announced November 2015.
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Non-standard Hubbard models in optical lattices: a review
Authors:
Omjyoti Dutta,
Mariusz Gajda,
Philipp Hauke,
Maciej Lewenstein,
Dirk-Sören Lühmann,
Boris A. Malomed,
Tomasz Sowiński,
Jakub Zakrzewski
Abstract:
Originally, the Hubbard model has been derived for describing the behaviour of strongly-correlated electrons in solids. However, since over a decade now, variations of it are also routinely being implemented with ultracold atoms in optical lattices. We review some of the rich literature on this subject, with a focus on more recent non-standard forms of the Hubbard model. After an introduction to s…
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Originally, the Hubbard model has been derived for describing the behaviour of strongly-correlated electrons in solids. However, since over a decade now, variations of it are also routinely being implemented with ultracold atoms in optical lattices. We review some of the rich literature on this subject, with a focus on more recent non-standard forms of the Hubbard model. After an introduction to standard (fermionic and bosonic) Hubbard models, we discuss briefly common models for mixtures, as well as the so called extended Bose-Hubbard models, that include interactions between neighboring sites, next-neighboring sites, and so on. The main part of the review discusses the importance of additional terms appearing when refining the tight-binding approximation on the original physical Hamiltonian. Even when restricting the models to the lowest Bloch band is justified, the standard approach neglects the density-induced tunneling (which has the same origin as the usual on-site interaction). The importance of these contributions is discussed for both contact and dipolar interactions. For sufficiently strong interactions, also the effects related to higher Bloch bands become important even for deep optical lattices. Different approaches that aim at incorporating these effects, mainly via dressing the basis Wannier functions with interactions, leading to effective, density-dependent Hubbard-type models, are reviewed. We discuss also examples of Hubbard-like models that explicitly involve higher $p$-orbitals, as well as models that couple dynamically spin and orbital degrees of freedom. Finally, we review mean-field nonlinear-Schrödinger models of the Salerno type that share with the non-standard Hubbard models the nonlinear coupling between the adjacent sites. In that part, discrete solitons are the main subject of the consideration. We conclude by listing some future open problems.
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Submitted 19 December, 2014; v1 submitted 1 June, 2014;
originally announced June 2014.
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Superfluidity of the BEC at finite temperature
Authors:
Lukasz Zawitkowski,
Mariusz Gajda,
Kazimierz Rzazewski
Abstract:
We use the classical fields approximation to study a translational flow of the condensate with respect to the thermal cloud in a weakly interacting Bose gas. We study both, subcritical and supercritical relative velocity cases and analyze in detail a state of stationary flow which is reached in the dynamics. This state corresponds to the thermal equilibrium, which is characterized by the relativ…
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We use the classical fields approximation to study a translational flow of the condensate with respect to the thermal cloud in a weakly interacting Bose gas. We study both, subcritical and supercritical relative velocity cases and analyze in detail a state of stationary flow which is reached in the dynamics. This state corresponds to the thermal equilibrium, which is characterized by the relative velocity of the condensate and the thermal cloud. The superfluidity manifests itself in the existence of many thermal equilibria varying in (the value of this velocity) the relative velocity between the condensate and the thermal cloud. We pay a particular attention to excitation spectra in a phonon as well as in a particle regime. Finally, we introduce a measure of the amount of the superfluid fraction in a weakly interacting Bose gas, allowing for the precise distinction between the superfluid and the condensed fractions in a single and consistent framework.
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Submitted 12 August, 2005;
originally announced August 2005.
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On the stability of Bose-Fermi mixtures
Authors:
T. Karpiuk,
M. Brewczyk,
M. Gajda,
K. Rzazewski
Abstract:
We consider the stability of a mixture of degenerate Bose and Fermi gases. Even though the bosons effectively repel each other the mixture can still collapse provided the Bose and Fermi gases attract each other strongly enough. For a given number of atoms and the strengths of the interactions between them we find the geometry of a maximally compact trap that supports the stable mixture. We compa…
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We consider the stability of a mixture of degenerate Bose and Fermi gases. Even though the bosons effectively repel each other the mixture can still collapse provided the Bose and Fermi gases attract each other strongly enough. For a given number of atoms and the strengths of the interactions between them we find the geometry of a maximally compact trap that supports the stable mixture. We compare a simple analytical estimation for the critical axial frequency of the trap with results based on the numerical solution of hydrodynamic equations for Bose-Fermi mixture.
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Submitted 29 March, 2005;
originally announced March 2005.