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- 1 October 2024
- Published by AIP Publishing in Review of Scientific Instruments
Adiabatic light guide with S-shaped strips
by B. Wojtsekhowski, E. J. Brash, G. B. Franklin, A. Rosso, A. Sarty, A. Shahinyan, E. Zimmerman
A light guide is an essential part of many scintillator counters and light collection systems. Our main interest is a light guide for a thin, wide scintillator that has high light transmission while converting the area of the light source to the shape of a photo-detector. We propose a variation of the light guide that avoids a 90° twist of the strips, reduces the length of the light pipe, and reduces the complexity of production. Detailed Monte Carlo simulation studies have been performed for a three-strip S-shaped light-guide system.
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- 1 October 2024
- Published by AIP Publishing in Review of Scientific Instruments
Adiabatic light guide with S-shaped strips
by B. Wojtsekhowski, E. J. Brash, G. B. Franklin, A. Rosso, A. Sarty, A. Shahinyan, E. Zimmerman
A light guide is an essential part of many scintillator counters and light collection systems. Our main interest is a light guide for a thin, wide scintillator that has high light transmission while converting the area of the light source to the shape of a photo-detector. We propose a variation of the light guide that avoids a 90° twist of the strips, reduces the length of the light pipe, and reduces the complexity of production. Detailed Monte Carlo simulation studies have been performed for a three-strip S-shaped light-guide system.
Open Access
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Cited by 31
- 26 August 2020
- Published by MDPI AG in Sensors
Quantitative Long-Term Monitoring of the Circulating Gases in the KATRIN Experiment Using Raman Spectroscopy
by Max Aker, Konrad Altenmüller, Armen Beglarian, Jan Behrens, Anatoly Berlev, Uwe Besserer, Benedikt Bieringer, Klaus Blaum, Fabian Block, Beate Bornschein, et al.
The Karlsruhe Tritium Neutrino (KATRIN) experiment aims at measuring the effective electron neutrino mass with a sensitivity of 0.2 eV/c², i.e., improving on previous measurements by an order of magnitude. Neutrino mass data taking with KATRIN commenced in early 2019, and after only a few weeks of data recording, analysis of these data showed the success of KATRIN, improving on the known neutrino mass limit by a factor of about two. This success very much could be ascribed to the fact that most of the system components met, or even surpassed, the required specifications during long-term operation. Here, we report on the performance of the laser Raman (LARA) monitoring system which provides continuous high-precision information on the gas composition injected into the experiment’s windowless gaseous tritium source (WGTS), specifically on its isotopic purity of tritium—one of the key parameters required in the derivation of the electron neutrino mass. The concentrations c_x for all six hydrogen isotopologues were monitored simultaneously, with a measurement precision for individual components of the order 10⁻³ or better throughout the complete KATRIN data taking campaigns to date. From these, the tritium purity, ε_T, is derived with precision of −3 and trueness of −3, being within and surpassing the actual requirements for KATRIN, respectively.
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- 26 August 2020
- Published by MDPI AG in Sensors
Open Access
Quantitative Long-Term Monitoring of the Circulating Gases in the KATRIN Experiment Using Raman Spectroscopy
by Max Aker, Konrad Altenmüller, Armen Beglarian, Jan Behrens, Anatoly Berlev, Uwe Besserer, Benedikt Bieringer, Klaus Blaum, Fabian Block, Beate Bornschein, et al.
The Karlsruhe Tritium Neutrino (KATRIN) experiment aims at measuring the effective electron neutrino mass with a sensitivity of 0.2 eV/c², i.e., improving on previous measurements by an order of magnitude. Neutrino mass data taking with KATRIN commenced in early 2019, and after only a few weeks of data recording, analysis of these data showed the success of KATRIN, improving on the known neutrino mass limit by a factor of about two. This success very much could be ascribed to the fact that most of the system components met, or even surpassed, the required specifications during long-term operation. Here, we report on the performance of the laser Raman (LARA) monitoring system which provides continuous high-precision information on the gas composition injected into the experiment’s windowless gaseous tritium source (WGTS), specifically on its isotopic purity of tritium—one of the key parameters required in the derivation of the electron neutrino mass. The concentrations c_x for all six hydrogen isotopologues were monitored simultaneously, with a measurement precision for individual components of the order 10⁻³ or better throughout the complete KATRIN data taking campaigns to date. From these, the tritium purity, ε_T, is derived with precision of −3 and trueness of −3, being within and surpassing the actual requirements for KATRIN, respectively.
Cited by 31
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Cited by 27
- 1 August 2018
- Published by IOP Publishing in Journal of Instrumentation
The KATRIN superconducting magnets: overview and first performance results
by M. Arenz, W.-J. Baek, M. Beck, A. Beglarian, J. Behrens, T. Bergmann, A. Berlev, U. Besserer, K. Blaum, T. Bode, et al.
The KATRIN experiment aims for the determination of the effective electron anti-neutrino mass from the tritium beta-decay with an unprecedented sub-eV sensitivity. The strong magnetic fields, designed for up to 6 T, adiabatically guide β-electrons from the source to the detector within a magnetic flux of 191 Tcm². A chain of ten single solenoid magnets and two larger superconducting magnet systems have been designed, constructed, and installed in the 70-m-long KATRIN beam line. The beam diameter for the magnetic flux varies from 0.064 m to 9 m, depending on the magnetic flux density along the beam line. Two transport and tritium pumping sections are assembled with chicane beam tubes to avoid direct "line-of-sight" molecular beaming effect of gaseous tritium molecules into the next beam sections. The sophisticated beam alignment has been successfully cross-checked by electron sources. In addition, magnet safety systems were developed to protect the complex magnet systems against coil quenches or other system failures. The main functionality of the magnet safety systems has been successfully tested with the two large magnet systems. The complete chain of the magnets was operated for several weeks at 70% of the design fields for the first test measurements with radioactive krypton gas. The stability of the magnetic fields of the source magnets has been shown to be better than 0.01% per month at 70% of the design fields. This paper gives an overview of the KATRIN superconducting magnets and reports on the first performance results of the magnets.
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- 1 August 2018
- Published by IOP Publishing in Journal of Instrumentation
Open Access
The KATRIN superconducting magnets: overview and first performance results
by M. Arenz, W.-J. Baek, M. Beck, A. Beglarian, J. Behrens, T. Bergmann, A. Berlev, U. Besserer, K. Blaum, T. Bode, et al.
The KATRIN experiment aims for the determination of the effective electron anti-neutrino mass from the tritium beta-decay with an unprecedented sub-eV sensitivity. The strong magnetic fields, designed for up to 6 T, adiabatically guide β-electrons from the source to the detector within a magnetic flux of 191 Tcm². A chain of ten single solenoid magnets and two larger superconducting magnet systems have been designed, constructed, and installed in the 70-m-long KATRIN beam line. The beam diameter for the magnetic flux varies from 0.064 m to 9 m, depending on the magnetic flux density along the beam line. Two transport and tritium pumping sections are assembled with chicane beam tubes to avoid direct "line-of-sight" molecular beaming effect of gaseous tritium molecules into the next beam sections. The sophisticated beam alignment has been successfully cross-checked by electron sources. In addition, magnet safety systems were developed to protect the complex magnet systems against coil quenches or other system failures. The main functionality of the magnet safety systems has been successfully tested with the two large magnet systems. The complete chain of the magnets was operated for several weeks at 70% of the design fields for the first test measurements with radioactive krypton gas. The stability of the magnetic fields of the source magnets has been shown to be better than 0.01% per month at 70% of the design fields. This paper gives an overview of the KATRIN superconducting magnets and reports on the first performance results of the magnets.
Cited by 27
Open Access
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Cited by 34
- 9 May 2018
- Published by Springer Nature in The European Physical Journal C
Calibration of high voltages at the ppm level by the difference of $^{83{\mathrm{m}}}$Kr conversion electron lines at the KATRIN experiment
by M. Arenz, W.-J. Baek, M. Beck, A. Beglarian, J. Behrens, T. Bergmann, A. Berlev, U. Besserer, K. Blaum, T. Bode, et al.
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- 9 May 2018
- Published by Springer Nature in The European Physical Journal C
Open Access
Calibration of high voltages at the ppm level by the difference of $^{83{\mathrm{m}}}$Kr conversion electron lines at the KATRIN experiment
by M. Arenz, W.-J. Baek, M. Beck, A. Beglarian, J. Behrens, T. Bergmann, A. Berlev, U. Besserer, K. Blaum, T. Bode, et al.
Cited by 34
Open Access
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Cited by 3
- 12 April 2017
- Published by EDP Sciences in EPJ Web of Conferences
The APEX experiment at JLab. Searching for the vector bosonA′ decaying toe+e−
by Gregg B. Franklin
EPJ Web of Conferences, open-access proceedings in physics and astronomy
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- 12 April 2017
- Published by EDP Sciences in EPJ Web of Conferences
Open Access
The APEX experiment at JLab. Searching for the vector bosonA′ decaying toe+e−
by Gregg B. Franklin
EPJ Web of Conferences, open-access proceedings in physics and astronomy
Cited by 3
Open Access
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Cited by 56
- 6 September 2016
- Published by American Physical Society (APS) in Physical Review D
Measurements of $d_{2}^{n}$ and $A_{1}^{n}$ : Probing the neutron spin structure
by D. Flay, M. Posik, D. S. Parno, K. Allada, W. R. Armstrong, T. Averett, F. Benmokhtar, W. Bertozzi, A. Camsonne, M. Canan, et al.
We report on the results of the E06-014 experiment performed at Jefferson Lab in Hall A, where a precision measurement of the twist-3 matrix element $d_{2}$ of the neutron ( $d_{2}^{n}$ ) was conducted. The quantity $d_{2}^{n}$ represents the average color Lorentz force a struck quark experiences in a deep inelastic electron scattering event off a neutron due to its interaction with the hadronizing remnants. This color force was determined from a linear combination of the third moments of the ${}^{3}{He}$ spin structure functions, $g_{1}$ and $g_{2}$ , after nuclear corrections had been applied to these moments. The structure functions were obtained from a measurement of the unpolarized cross section and of double-spin asymmetries in the scattering of a longitudinally polarized electron beam from a transversely and a longitudinally polarized ${}^{3}{He}$ target. The measurement kinematics included two average $Q^{2}$ bins of $3.2 {GeV}^{2}$ and $4.3 {GeV}^{2}$ , and Bjorken- $x$ $0.25 \leq x \leq 0.90$ covering the deep inelastic and resonance regions. We have found that $d_{2}^{n}$ is small and negative for $⟨ Q^{2} ⟩ = 3.2 {GeV}^{2}$ , and even smaller for $⟨ Q^{2} ⟩ = 4.3 {GeV}^{2}$ , consistent with the results of a lattice QCD calculation. The twist-4 matrix element $f_{2}^{n}$ was extracted by combining our measured $d_{2}^{n}$ with the world data on the first moment in $x$ of $g_{1}^{n}$ , $Γ_{1}^{n}$ . We found $f_{2}^{n}$ to be roughly an order of magnitude larger than $d_{2}^{n}$ . Utilizing the extracted $d_{2}^{n}$ and $f_{2}^{n}$ data, we separated the Lorentz color force into its electric and magnetic components, $F_{E}^{y, n}$ and $F_{B}^{y, n}$ , and found them to be equal and opposite in magnitude, in agreement with the predictions from an instanton model but not with those from QCD sum rules. Furthermore, using the measured double-spin asymmetries, we have extracted the virtual photon-nucleon asymmetry on the neutron $A_{1}^{n}$ , the structure function ratio $g_{1}^{n} / F_{1}^{n}$ , and the quark ratios $(Δ u + Δ \bar{u}) / (u + \bar{u})$ and $(Δ d + Δ \bar{d}) / (d + \bar{d})$ . These results were found to be consistent with deep-inelastic scattering world data and with the prediction of the constituent quark model but at odds with the perturbative quantum chromodynamics predictions at large $x$ .
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- 6 September 2016
- Published by American Physical Society (APS) in Physical Review D
Open Access
Measurements of $d_{2}^{n}$ and $A_{1}^{n}$ : Probing the neutron spin structure
by D. Flay, M. Posik, D. S. Parno, K. Allada, W. R. Armstrong, T. Averett, F. Benmokhtar, W. Bertozzi, A. Camsonne, M. Canan, et al.
We report on the results of the E06-014 experiment performed at Jefferson Lab in Hall A, where a precision measurement of the twist-3 matrix element $d_{2}$ of the neutron ( $d_{2}^{n}$ ) was conducted. The quantity $d_{2}^{n}$ represents the average color Lorentz force a struck quark experiences in a deep inelastic electron scattering event off a neutron due to its interaction with the hadronizing remnants. This color force was determined from a linear combination of the third moments of the ${}^{3}{He}$ spin structure functions, $g_{1}$ and $g_{2}$ , after nuclear corrections had been applied to these moments. The structure functions were obtained from a measurement of the unpolarized cross section and of double-spin asymmetries in the scattering of a longitudinally polarized electron beam from a transversely and a longitudinally polarized ${}^{3}{He}$ target. The measurement kinematics included two average $Q^{2}$ bins of $3.2 {GeV}^{2}$ and $4.3 {GeV}^{2}$ , and Bjorken- $x$ $0.25 \leq x \leq 0.90$ covering the deep inelastic and resonance regions. We have found that $d_{2}^{n}$ is small and negative for $⟨ Q^{2} ⟩ = 3.2 {GeV}^{2}$ , and even smaller for $⟨ Q^{2} ⟩ = 4.3 {GeV}^{2}$ , consistent with the results of a lattice QCD calculation. The twist-4 matrix element $f_{2}^{n}$ was extracted by combining our measured $d_{2}^{n}$ with the world data on the first moment in $x$ of $g_{1}^{n}$ , $Γ_{1}^{n}$ . We found $f_{2}^{n}$ to be roughly an order of magnitude larger than $d_{2}^{n}$ . Utilizing the extracted $d_{2}^{n}$ and $f_{2}^{n}$ data, we separated the Lorentz color force into its electric and magnetic components, $F_{E}^{y, n}$ and $F_{B}^{y, n}$ , and found them to be equal and opposite in magnitude, in agreement with the predictions from an instanton model but not with those from QCD sum rules. Furthermore, using the measured double-spin asymmetries, we have extracted the virtual photon-nucleon asymmetry on the neutron $A_{1}^{n}$ , the structure function ratio $g_{1}^{n} / F_{1}^{n}$ , and the quark ratios $(Δ u + Δ \bar{u}) / (u + \bar{u})$ and $(Δ d + Δ \bar{d}) / (d + \bar{d})$ . These results were found to be consistent with deep-inelastic scattering world data and with the prediction of the constituent quark model but at odds with the perturbative quantum chromodynamics predictions at large $x$ .
Cited by 56
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Cited by 9
- 1 June 2016
- Published by Elsevier in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
A high-finesse Fabry–Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab
by A. Rakhman, M. Hafez, S. Nanda, F. Benmokhtar, A. Camsonne, G.D. Cates, M.M. Dalton, G.B. Franklin, M. Friend, R.W. Michaels, et al.
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- 1 June 2016
- Published by Elsevier in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
A high-finesse Fabry–Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab
by A. Rakhman, M. Hafez, S. Nanda, F. Benmokhtar, A. Camsonne, G.D. Cates, M.M. Dalton, G.B. Franklin, M. Friend, R.W. Michaels, et al.
Cited by 9
Open Access
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Cited by 56
- 16 April 2015
- Published by American Physical Society (APS) in Physical Review C
Measurement of parity-violating asymmetry in electron-deuteron inelastic scattering
by D. Wang, K. Pan, R. Subedi, Z. Ahmed, K. Allada, K. A. Aniol, D. S. Armstrong, J. Arrington, V. Bellini, R. Beminiwattha, et al.
The parity-violating asymmetries between a longitudinally polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep-inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were published earlier, but are presented here in more detail.
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- 16 April 2015
- Published by American Physical Society (APS) in Physical Review C
Open Access
Measurement of parity-violating asymmetry in electron-deuteron inelastic scattering
by D. Wang, K. Pan, R. Subedi, Z. Ahmed, K. Allada, K. A. Aniol, D. S. Armstrong, J. Arrington, V. Bellini, R. Beminiwattha, et al.
The parity-violating asymmetries between a longitudinally polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep-inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were published earlier, but are presented here in more detail.
Cited by 56
Open Access
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Cited by 39
- 11 July 2014
- Published by American Physical Society (APS) in Physical Review Letters
Precision Measurement of the Neutron Twist-3 Matrix Element $d_{2}^{n}$ : Probing Color Forces
by M Posik, D Flay, D S Parno, K Allada, W Armstrong, T Averett, F Benmokhtar, W Bertozzi, A Camsonne, M Canan, et al.
Double-spin asymmetries and absolute cross sections were measured at large Bjorken $x (0.25 \leq x \leq 0.90)$ , in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized ${}^{3}{He}$ target. In this dedicated experiment, the spin structure function $g_{2}^{{}^{3}{He}}$ was determined with precision at large $x$ , and the neutron twist-3 matrix element $d_{2}^{n}$ was measured at $⟨ Q^{2} ⟩$ of 3.21 and $4.32 {GeV}^{2} / c^{2}$ , with an absolute precision of about $1 0^{- 5}$ . Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at $⟨ Q^{2} ⟩ = 5 {GeV}^{2} / c^{2}$ . Combining $d_{2}^{n}$ and a newly extracted twist-4 matrix element $f_{2}^{n}$ , the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about $30 MeV / fm$ in magnitude.
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- 11 July 2014
- Published by American Physical Society (APS) in Physical Review Letters
Open Access
Precision Measurement of the Neutron Twist-3 Matrix Element $d_{2}^{n}$ : Probing Color Forces
by M Posik, D Flay, D S Parno, K Allada, W Armstrong, T Averett, F Benmokhtar, W Bertozzi, A Camsonne, M Canan, et al.
Double-spin asymmetries and absolute cross sections were measured at large Bjorken $x (0.25 \leq x \leq 0.90)$ , in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized ${}^{3}{He}$ target. In this dedicated experiment, the spin structure function $g_{2}^{{}^{3}{He}}$ was determined with precision at large $x$ , and the neutron twist-3 matrix element $d_{2}^{n}$ was measured at $⟨ Q^{2} ⟩$ of 3.21 and $4.32 {GeV}^{2} / c^{2}$ , with an absolute precision of about $1 0^{- 5}$ . Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at $⟨ Q^{2} ⟩ = 5 {GeV}^{2} / c^{2}$ . Combining $d_{2}^{n}$ and a newly extracted twist-4 matrix element $f_{2}^{n}$ , the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about $30 MeV / fm$ in magnitude.
Cited by 39
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Cited by 9
- 1 November 2013
- Published by Elsevier in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Comparison of modeled and measured performance of a GSO crystal as gamma detector
by D.S. Parno, M. Friend, V. Mamyan, F. Benmokhtar, A. Camsonne, G.B. Franklin, K. Paschke, B. Quinn
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- 1 November 2013
- Published by Elsevier in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Comparison of modeled and measured performance of a GSO crystal as gamma detector
by D.S. Parno, M. Friend, V. Mamyan, F. Benmokhtar, A. Camsonne, G.B. Franklin, K. Paschke, B. Quinn
Cited by 9

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