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Commissioning the Resonance Ionization Spectroscopy Experiment at FRIB
Authors:
A. J. Brinson,
B. J. Rickey,
J. M. Allmond,
A. Dockery,
A. Fernandez Chiu,
R. F. Garcia Ruiz,
T. J. Gray,
J. Karthein,
T. T. King,
K. Minamisono,
A. Ortiz-Cortes,
S. V. Pineda,
M. Reponen,
B. C. Rasco,
S. M. Udrescu,
A. R. Vernon,
S. G. Wilkins
Abstract:
This manuscript reports on the commissioning of the Resonance Ionization Spectroscopy Experiment (RISE) at the BECOLA facility at FRIB. The new instrument implements the collinear resonance ionization spectroscopy technique for sensitive measurements of isotope shifts and hyperfine structure of short-lived isotopes produced at FRIB. The existing BECOLA beamline was extended to integrate an electro…
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This manuscript reports on the commissioning of the Resonance Ionization Spectroscopy Experiment (RISE) at the BECOLA facility at FRIB. The new instrument implements the collinear resonance ionization spectroscopy technique for sensitive measurements of isotope shifts and hyperfine structure of short-lived isotopes produced at FRIB. The existing BECOLA beamline was extended to integrate an electrostatic ion-beam bender and an ion detector at ultra-high vacuum. An injection-seeded Ti:Sapphire laser and a multi-harmonic pulsed Nd:YAG laser were installed to perform resonant excitation and selective ionization. Commissioning tests were performed to demonstrate the capabilities of the new instrument by measuring the hyperfine structure of stable $^{27}$Al produced in an offline ion source. The RISE instrument is ready and operational for future studies of short-lived isotopes at FRIB.
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Submitted 17 February, 2026; v1 submitted 11 November, 2025;
originally announced November 2025.
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Object Detection with Deep Learning for Rare Event Search in the GADGET II TPC
Authors:
Tyler Wheeler,
S. Ravishankar,
C. Wrede,
A. Andalib,
A. Anthony,
Y. Ayyad,
B. Jain,
A. Jaros,
R. Mahajan,
L. Schaedig,
A. Adams,
S. Ahn,
J. M. Allmond,
D. Bardayan,
D. Bazin,
K. Bosmpotinis,
T. Budner,
S. R. Carmichael,
S. M. Cha,
A. Chen,
K. A. Chipps,
J. M. Christie,
I. Cox,
J. Dopfer,
M. Friedman
, et al. (28 additional authors not shown)
Abstract:
In the pursuit of identifying rare two-particle events within the GADGET II Time Projection Chamber (TPC), this paper presents a comprehensive approach for leveraging Convolutional Neural Networks (CNNs) and various data processing methods. To address the inherent complexities of 3D TPC track reconstructions, the data is expressed in 2D projections and 1D quantities. This approach capitalizes on t…
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In the pursuit of identifying rare two-particle events within the GADGET II Time Projection Chamber (TPC), this paper presents a comprehensive approach for leveraging Convolutional Neural Networks (CNNs) and various data processing methods. To address the inherent complexities of 3D TPC track reconstructions, the data is expressed in 2D projections and 1D quantities. This approach capitalizes on the diverse data modalities of the TPC, allowing for the efficient representation of the distinct features of the 3D events, with no loss in topology uniqueness. Additionally, it leverages the computational efficiency of 2D CNNs and benefits from the extensive availability of pre-trained models. Given the scarcity of real training data for the rare events of interest, simulated events are used to train the models to detect real events. To account for potential distribution shifts when predominantly depending on simulations, significant perturbations are embedded within the simulations. This produces a broad parameter space that works to account for potential physics parameter and detector response variations and uncertainties. These parameter-varied simulations are used to train sensitive 2D CNN object detectors. When combined with 1D histogram peak detection algorithms, this multi-modal detection framework is highly adept at identifying rare, two-particle events in data taken during experiment 21072 at the Facility for Rare Isotope Beams (FRIB), demonstrating a 100% recall for events of interest. We present the methods and outcomes of our investigation and discuss the potential future applications of these techniques.
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Submitted 28 January, 2025;
originally announced January 2025.
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CLARION2-TRINITY: a Compton-suppressed HPGe and GAGG:Ce-Si-Si array for absolute cross-section measurements with heavy ions
Authors:
T. J. Gray,
J. M. Allmond,
D. T. Dowling,
M. Febbraro,
T. T. King,
S. D. Pain,
D. W. Stracener,
S. Ajayi,
J. Aragon,
L. Baby,
P. Barber,
C. Benetti,
S. Bhattacharya,
R. Boisseau,
J. Gibbons,
S. L. Tabor,
V. Tripathi,
C. Wibisono,
I. Wiedenhoever,
L. Bignell,
M. S. M. Gerathy,
G. Lane,
L. J. McKie,
A. J. Mitchell,
J. Pope
, et al. (4 additional authors not shown)
Abstract:
The design and performance of a new Compton-suppressed HPGe and charged-particle array, CLARION2-TRINITY, are described. The TRINITY charged-particle array is comprised of 64 Cerium-doped Gadolinium Aluminium Gallium Garnet (GAGG:Ce) crystals configured into five rings spanning 7-54 degrees, and two annular silicon detectors that can shadow or extend the angular coverage to backward angles with mi…
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The design and performance of a new Compton-suppressed HPGe and charged-particle array, CLARION2-TRINITY, are described. The TRINITY charged-particle array is comprised of 64 Cerium-doped Gadolinium Aluminium Gallium Garnet (GAGG:Ce) crystals configured into five rings spanning 7-54 degrees, and two annular silicon detectors that can shadow or extend the angular coverage to backward angles with minimal $γ$-ray attenuation. GAGG:Ce is a non-hygroscopic, bright, and relatively fast scintillator with a light distribution well matched to SiPMs. Count rates up to 40 kHz per crystal are sustainable. Fundamental characteristics of GAGG:Ce are measured and presented, including light- and heavy-ion particle identification (PID) capability, pulse-height defects, radiation hardness, and emission spectra. The CLARION2 array consists of up to 16 Compton-suppressed HPGe Clover detectors ($\approx4\%$ efficiency at 1 MeV) configured into four rings (eight HPGe crystal rings) using a non-Archimedean geometry that suppresses back-to-back coincident 511-keV gamma rays. The entire array is instrumented with 100- and 500-MHz (14 bit) waveform digitizers which enable triggerless operation, pulse-shape discrimination, fast timing, and pileup correction. Finally, two examples of experimental data taken during the commissioning of the CLARION2-TRINITY system are given: a PID spectrum from $^{16}$O + $^{18}$O fusion-evaporation, and PID and Doppler-corrected $γ$-ray spectra from $^{48}$Ti + $^{12}$C Coulomb excitation.
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Submitted 10 August, 2022;
originally announced August 2022.
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Pulse Shape Discrimination of low-energy nuclear and electron recoils for improved particle identification in NaI:Tl
Authors:
N. J. Spinks,
L. J. Bignell,
G. J. Lane,
A. Akber,
E. Barberio,
T. Baroncelli,
B. J. Coombes,
J. T. H. Dowie,
T. K. Eriksen,
M. S. M. Gerathy,
T. J. Gray,
I. Mahmood,
B. P. McCormick,
W. J. D. Melbourne,
A. J. Mitchell,
F. Nuti,
M. S. Rahman,
F. Scutti,
A. E. Stuchbery,
H. Timmers,
P. Urquijo,
Y. Y. Zhong,
M. J. Zurowski
Abstract:
The scintillation mechanism in NaI:Tl crystals produces different pulse shapes that are dependent on the incoming particle type. The time distribution of scintillation light from nuclear recoil events decays faster than for electron recoil events and this difference can be categorised using various Pulse Shape Discrimination (PSD) techniques. In this study, we measured nuclear and electron recoils…
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The scintillation mechanism in NaI:Tl crystals produces different pulse shapes that are dependent on the incoming particle type. The time distribution of scintillation light from nuclear recoil events decays faster than for electron recoil events and this difference can be categorised using various Pulse Shape Discrimination (PSD) techniques. In this study, we measured nuclear and electron recoils in a NaI:Tl crystal, with electron equivalent energies between 2 and 40 keV. We report on a new PSD approach, based on an event-type likelihood; this outperforms the charge-weighted mean-time, which is the conventional metric for PSD in NaI:Tl. Furthermore, we show that a linear combination of the two methods improves the discrimination power at these energies.
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Submitted 18 May, 2022;
originally announced May 2022.
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Quenching factor measurements of sodium nuclear recoils in NaI:Tl determined by spectrum fitting
Authors:
L. J. Bignell,
I. Mahmood,
F. Nuti,
G. J. Lane,
A. Akber,
E. Barberio,
T. Baroncelli,
B. Coombes,
W. Dix,
J. T. H. Dowie,
T. Eriksen,
M. S. M. Gerathy,
T. J. Gray,
B. P. McCormick,
A. J. Mitchell,
M. S. Rahman,
F. Scutti,
N. J. Spinks,
A. E. Stuchbery,
H. Timmers,
P. Urquijo,
L. Wang,
Y. Y. Zhong,
M. Zurowski
Abstract:
We have performed measurements of sodium nuclear recoils in NaI:Tl crystals, following scattering by neutrons produced in a $^{7}$Li(p,n)$^{7}$Be reaction. Understanding the light output from such recoils, which is reduced relative to electrons of equivalent energy by the quenching factor, is critical to interpret dark matter experiments that search for nuclear scattering interactions. We have dev…
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We have performed measurements of sodium nuclear recoils in NaI:Tl crystals, following scattering by neutrons produced in a $^{7}$Li(p,n)$^{7}$Be reaction. Understanding the light output from such recoils, which is reduced relative to electrons of equivalent energy by the quenching factor, is critical to interpret dark matter experiments that search for nuclear scattering interactions. We have developed a spectrum-fitting methodology to extract the quenching factor from our measurements, and report quenching factors for nuclear recoil energies between 36 and 401 keV. Our results agree with other recent quenching factor measurements that use quasi-monoenergetic neutron sources. The new method will be applied in the future to the NaI:Tl crystals used in the SABRE experiment.
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Submitted 15 April, 2021; v1 submitted 4 February, 2021;
originally announced February 2021.
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Allotaxonometry and rank-turbulence divergence: A universal instrument for comparing complex systems
Authors:
P. S. Dodds,
J. R. Minot,
M. V. Arnold,
T. Alshaabi,
J. L. Adams,
D. R. Dewhurst,
T. J. Gray,
M. R. Frank,
A. J. Reagan,
C. M. Danforth
Abstract:
Complex systems often comprise many kinds of components which vary over many orders of magnitude in size: Populations of cities in countries, individual and corporate wealth in economies, species abundance in ecologies, word frequency in natural language, and node degree in complex networks. Here, we introduce `allotaxonometry' along with `rank-turbulence divergence' (RTD), a tunable instrument fo…
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Complex systems often comprise many kinds of components which vary over many orders of magnitude in size: Populations of cities in countries, individual and corporate wealth in economies, species abundance in ecologies, word frequency in natural language, and node degree in complex networks. Here, we introduce `allotaxonometry' along with `rank-turbulence divergence' (RTD), a tunable instrument for comparing any two ranked lists of components. We analytically develop our rank-based divergence in a series of steps, and then establish a rank-based allotaxonograph which pairs a map-like histogram for rank-rank pairs with an ordered list of components according to divergence contribution. We explore the performance of rank-turbulence divergence, which we view as an instrument of `type calculus', for a series of distinct settings including: Language use on Twitter and in books, species abundance, baby name popularity, market capitalization, performance in sports, mortality causes, and job titles. We provide a series of supplementary flipbooks which demonstrate the tunability and storytelling power of rank-based allotaxonometry.
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Submitted 2 August, 2023; v1 submitted 22 February, 2020;
originally announced February 2020.
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Hahahahaha, Duuuuude, Yeeessss!: A two-parameter characterization of stretchable words and the dynamics of mistypings and misspellings
Authors:
Tyler J. Gray,
Christopher M. Danforth,
Peter Sheridan Dodds
Abstract:
Stretched words like `heellllp' or `heyyyyy' are a regular feature of spoken language, often used to emphasize or exaggerate the underlying meaning of the root word. While stretched words are rarely found in formal written language and dictionaries, they are prevalent within social media. In this paper, we examine the frequency distributions of `stretchable words' found in roughly 100 billion twee…
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Stretched words like `heellllp' or `heyyyyy' are a regular feature of spoken language, often used to emphasize or exaggerate the underlying meaning of the root word. While stretched words are rarely found in formal written language and dictionaries, they are prevalent within social media. In this paper, we examine the frequency distributions of `stretchable words' found in roughly 100 billion tweets authored over an 8 year period. We introduce two central parameters, `balance' and `stretch', that capture their main characteristics, and explore their dynamics by creating visual tools we call `balance plots' and `spelling trees'. We discuss how the tools and methods we develop here could be used to study the statistical patterns of mistypings and misspellings, along with the potential applications in augmenting dictionaries, improving language processing, and in any area where sequence construction matters, such as genetics.
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Submitted 8 July, 2019;
originally announced July 2019.
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English verb regularization in books and tweets
Authors:
Tyler J. Gray,
Andrew J. Reagan,
Peter Sheridan Dodds,
Christopher M. Danforth
Abstract:
The English language has evolved dramatically throughout its lifespan, to the extent that a modern speaker of Old English would be incomprehensible without translation. One concrete indicator of this process is the movement from irregular to regular (-ed) forms for the past tense of verbs. In this study we quantify the extent of verb regularization using two vastly disparate datasets: (1) Six year…
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The English language has evolved dramatically throughout its lifespan, to the extent that a modern speaker of Old English would be incomprehensible without translation. One concrete indicator of this process is the movement from irregular to regular (-ed) forms for the past tense of verbs. In this study we quantify the extent of verb regularization using two vastly disparate datasets: (1) Six years of published books scanned by Google (2003--2008), and (2) A decade of social media messages posted to Twitter (2008--2017). We find that the extent of verb regularization is greater on Twitter, taken as a whole, than in English Fiction books. Regularization is also greater for tweets geotagged in the United States relative to American English books, but the opposite is true for tweets geotagged in the United Kingdom relative to British English books. We also find interesting regional variations in regularization across counties in the United States. However, once differences in population are accounted for, we do not identify strong correlations with socio-demographic variables such as education or income.
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Submitted 3 January, 2019; v1 submitted 26 March, 2018;
originally announced March 2018.