Experiment neutrino-4 on searching for a sterile neutrino with multisection detector model

Serebrov, A. P.; Ivochkin, V. G.; Samoilov, R. M.; Fomin, A. K.; Zinov’ev, V. G.; Neustroev, P.; Golovtsov, V.; Chernyi, A. V.; Zherebtsov, O. M.; Polyushkin, A. O.; Martemyanov, V. P.; Tarasenkov, V. G.; Aleshin, V. I.; Петелин, А. Л.; Izhutov, A. L.; Tuzov, A. A.; Sazontov, S. A.; Ryazanov, D. K.; Gromov, M. O.; Афанасьев, В. В.; Zaitsev, M. E.; Chaikovskii, M. E.

doi:10.1134/s1063784217020268

Cited by 8 publications

(5 citation statements)

References 8 publications

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“…Monte Carlo calculations has shown that 63% of prompt signals from neutrino events are recorded within one section and only 37% of events has signal in another section [6]. In our measurements, the signal difference at the reactor ON and OFF has ratio of double and single prompt events integrated over all distances (37 4)%  and (63 7)%  .…”

Section: Detector Designmentioning

confidence: 57%

“…Unfortunately, a more detailed analysis of that ratio cannot be performed due to low statistical accuracy. Yet, it should be noted, that the measurements of fast neutrons and gamma fluxes in dependence on distance and reactor power were made before installing the detector into passive shielding [6,7]. Absence of noticeable dependence of the background on both distance and reactor power was observed.…”

Section: Detector Designmentioning

confidence: 99%

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First Observation of the Oscillation Effect in the Neutrino-4 Experiment on the Search for the Sterile Neutrino

et al. 2019

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We report Neutrino-4 experiment results of measurements of reactor antineutrinos flux and spectrum dependence on the distance in range 6-12 meters from the center of the reactor core. The fit of experimental dependence with the law 1 L 2 ⁄ , where L is the distance from the reactor center, gave satisfactory result with goodness of fit 81%. However, we discovered that the experimental neutrino spectrum is different from the calculated one. Using experimental spectrum, we performed the model independent analysis of restrictions on oscillation parameters ∆m 14 2 and sin 2 2 14 . The results of this analysis exclude area of reactor and gallium anomaly at CL more than 99.7% (> 3 ) for values ∆m 14 2 < 3eV 2 and sin 2 2θ 14 > 0.1 However, we observed an oscillation effect at CL 2.8 in vicinity of ∆m 14 2 ≈ 7.34eV 2 and sin 2 2θ 14 ≈ 0.39. The method of coherent addition of results of measurements, which allows us to directly observe the effect of oscillations, is proposed. The analysis of that effect is presented. In general, it seems that the effect predicted in gallium and reactor experiments is confirmed but at sufficiently large value of ∆m 14 2 . Future prospects of the experiment are discussed.

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Section: Detector Designmentioning

confidence: 57%

Section: Detector Designmentioning

confidence: 99%

First Observation of the Oscillation Effect in the Neutrino-4 Experiment on the Search for the Sterile Neutrino

et al. 2019

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“…The Neutrino-4 experiment started in 2014, at first on a model, then on a full-scale detector and, for the first time in the world, has provided measurement data on dependence of the reactor antineutrinos flux on the distance within 6 -12 meters [17][18][19][20]. Attempts to suppress the background of fast neutrons by means of sectioning the detector has given the required result.…”

Section: Conclusion On the Current Experimental Resultsmentioning

confidence: 99%

“…Monte Carlo calculations shown that 63% of starting signals from neutrino events can be also recorded within one section. Only 37% of neutrino starting signals is multi-sectional due to registration of γ quanta in the sections adjacent to that, in which positron annihilation occurs [6]. Thus, if signal difference between the reactor ON and reactor OFF measurements is within 37% -63% for the multi section and single-section events, then it can be interpreted as a neutrino signal.…”

Section: Full-scale Antineutrino Detectormentioning

confidence: 99%

Status of Experiment NEUTRINO-4 Search for Sterile Neutrino

Serebrov

Ivochkin

Samoilov

et al. 2017

J. Phys.: Conf. Ser.

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The experiment "Neutrino-4" started in 2014 on a model, then it was continued on a full-scale detector, and now, has provided the measurement result on dependence of the flux and spectrum of reactor antineutrinos on the distance of 6 -12 meters from the center of the reactor. One of the main problems is the correlated background from fast neutrons caused by space radiation. Attempts to suppress the background of fast neutrons by sectioning the detector have given some result. The relation of signal/background has improved up to 0.6. As a result, measurements of the difference in the counting rate of neutrino-like events (reactor ON-reactor OFF) have been obtained as dependence on distance from the reactor center. The fit of experimental dependence with the law 2 1/ L give satisfactory result.The goodness of that fit is 81%. However, there was discovered experimental neutrino spectrum difference from calculated one. With achieved accuracy this difference does not change with distance. Therefore it cannot be interpreted as oscillations. Calculated spectrum form correction for experimental allow us to make proper analysis of oscillation parameters 2 14 m  and 2 14 sin (2 )  limitations. Result of this analysis is exclusion of reactor and gallium anomalies area with 95% CL. Experiment future perspectives are discussed.

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“…The inconclusive interpretations based on the current world neutrino oscillation data justify an active program of new short baseline oscillation searches near reactors and accelerators. Some of these are already taking data [20][21][22], while others are currently being commissioned, or under construction [23,24].…”

Section: Introductionmentioning

confidence: 99%

Performance of a full scale prototype detector at the BR2 reactor for the SoLid experiment

Abreu¹,

Giot²,

Pestel³

et al. 2018

J. Inst.

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A : The SoLid collaboration has developed a new detector technology to detect electron anti-neutrinos at close proximity to the Belgian BR2 reactor at surface level. A 288 kg prototype detector was deployed in 2015 and collected data during the operational period of the reactor and during reactor shut-down. Dedicated calibration campaigns were also performed with gamma and neutron sources.This paper describes the construction of the prototype detector with a high control on its proton content and the stability of its operation over a period of several months after deployment at the BR2 reactor site. All detector cells provide sufficient light yields to achieve a target energy resolution of better than 20%/ E(MeV). The capability of the detector to track muons is exploited to equalize the light response of a large number of channels to a precision of 3% and to demonstrate the stability of the energy scale over time. Particle identification based on pulse-shape discrimination is demonstrated with calibration sources. Despite a lower neutron detection efficiency due to triggering constraints, the main backgrounds at the reactor site were determined and taken into account in the shielding strategy for the main experiment. The results obtained with this prototype proved essential in the design optimization of the final detector.This paper is dedicated to our SCK · CEN colleague, Edgar Koonen, who passed away unexpectedly in 2017. Edgar was part of the SoLid collaboration since its inception and his efforts were vital to get the experiment started. He will be duly missed.

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Experiment neutrino-4 on searching for a sterile neutrino with multisection detector model

Cited by 8 publications

References 8 publications

First Observation of the Oscillation Effect in the Neutrino-4 Experiment on the Search for the Sterile Neutrino

First Observation of the Oscillation Effect in the Neutrino-4 Experiment on the Search for the Sterile Neutrino

Status of Experiment NEUTRINO-4 Search for Sterile Neutrino

Performance of a full scale prototype detector at the BR2 reactor for the SoLid experiment

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