This paper presents an energy calibration scheme for an upgraded reactor antineutrino detector for the Precision Reactor Oscillation and Spectrum Experiment (PROSPECT). The PROSPECT collaboration is ...preparing an upgraded detector, PROSPECT-II (P-II), to advance capabilities for the investigation of fundamental neutrino physics, fission processes and associated reactor neutrino flux, and nuclear security applications. P-II will expand the statistical power of the original PROSPECT (P-I) dataset by at least an order of magnitude. The new design builds upon previous P-I design and focuses on improving the detector robustness and long-term stability to enable multi-year operation at one or more sites. The new design optimizes the fiducial volume by elimination of dead space previously occupied by internal calibration channels, which in turn necessitates the external deployment. In this paper, we describe a calibration strategy for P-II. The expected performance of externally deployed calibration sources is evaluated using P-I data and a well-benchmarked simulation package by varying detector segmentation configurations in the analysis. The proposed external calibration scheme delivers a compatible energy scale model and achieves comparable performance with the inclusion of an additional AmBe neutron source, in comparison to the previous internal arrangement. Most importantly, the estimated uncertainty contribution from the external energy scale calibration model meets the precision requirements of the P-II experiment.
This study evaluated various methods of applying force to collagenous tissue at various temperatures to produce permanent elongation, using rat tail tendon as the tissue model. A materials testing ...machine was used to measure the forces applied and the resulting elongation produced by differing procedures. Short-term vigorous stretching and prolonged moderate stretching were compared at 37 C. The effect of heating tissue prior to applying force was evaluated, and the effect of using a prolonged application of low force was demonstrated. The data showed that the low force, long duration procedure was very effective at producing residual elongation. Elevating tissue temperature and maintaining it prior to applying force was found to cause significantly less damage; and finally, the lower loads applied at elevated temperatures for prolonged periods were found to produce significantly greater residual elongation.
The Precision Reactor Oscillation and Spectrum Experiment, PROSPECT, has made world-leading measurements of reactor antineutrinos at short baselines. In its first phase, conducted at the High Flux ...Isotope Reactor (HFIR) at Oak Ridge National Laboratory, PROSPECT produced some of the strongest limits on eV-scale sterile neutrinos, made a precision measurement of the reactor antineutrino spectrum from \(^{235}\)U, and demonstrated the observation of reactor antineutrinos in an aboveground detector with good energy resolution and well-controlled backgrounds. The PROSPECT collaboration is now preparing an upgraded detector, PROSPECT-II, to probe yet unexplored parameter space for sterile neutrinos and contribute to a full resolution of the Reactor Antineutrino Anomaly, a longstanding puzzle in neutrino physics. By pressing forward on the world's most precise measurement of the \(^{235}\)U antineutrino spectrum and measuring the absolute flux of antineutrinos from \(^{235}\)U, PROSPECT-II will sharpen a tool with potential value for basic neutrino science, nuclear data validation, and nuclear security applications. Following a two-year deployment at HFIR, an additional PROSPECT-II deployment at a low enriched uranium reactor could make complementary measurements of the neutrino yield from other fission isotopes. PROSPECT-II provides a unique opportunity to continue the study of reactor antineutrinos at short baselines, taking advantage of demonstrated elements of the original PROSPECT design and close access to a highly enriched uranium reactor core.
The PROSPECT experiment has substantially addressed the original 'Reactor Antineutrino Anomaly' by performing a high-resolution spectrum measurement from an enriched compact reactor core and a ...reactor model-independent sterile neutrino oscillation search based on the unique spectral distortions the existence of eV\(^2\)-scale sterile neutrinos would impart. But as the field has evolved, the current short-baseline (SBL) landscape supports many complex phenomenological interpretations, establishing a need for complementary experimental approaches to resolve the situation. While the global suite of SBL reactor experiments, including PROSPECT, have probed much of the sterile neutrino parameter space, there remains a large region above 1 eV\(^2\) that remains unaddressed. Recent results from BEST confirm the Gallium Anomaly, increasing its significance to \(\sim 5\sigma\), with sterile neutrinos providing a possible explanation of this anomaly. Separately, the MicroBooNE exclusion of electron-like signatures causing the MiniBooNE low-energy excess does not eliminate the possibility of sterile neutrinos as an explanation. Focusing specifically on the future use of reactors as a neutrino source for beyond-the-standard-model physics and applications, higher-precision spectral measurements still have a role to play. These recent results have created a confusing landscape which requires new data to disentangle the seemingly contradictory measurements. To directly probe \(\overline{\nu}_{e}\) disappearance from high \(\Delta m^2\) sterile neutrinos, the PROSPECT collaboration proposes to build an upgraded and improved detector, PROSPECT-II. It features an evolutionary detector design which can be constructed and deployed within one year and have impactful physics with as little as one calendar year of data.
If dark matter has mass lower than around 1 GeV, it will not impart enough energy to cause detectable nuclear recoils in many direct-detection experiments. However, if dark matter is upscattered to ...high energy by collisions with cosmic rays, it may be detectable in both direct-detection experiments and neutrino experiments. We report the results of a dedicated search for boosted dark matter upscattered by cosmic rays using the PROSPECT reactor antineutrino experiment. We show that such a flux of upscattered dark matter would display characteristic diurnal sidereal modulation, and use this to set new experimental constraints on sub-GeV dark matter exhibiting large interaction cross-sections.
The PROSPECT and STEREO collaborations present a combined measurement of the pure \(^{235}\)U antineutrino spectrum, without site specific corrections or detector-dependent effects. The spectral ...measurements of the two highest precision experiments at research reactors are found to be compatible with \(\chi^2/\mathrm{ndf} = 24.1/21\), allowing a joint unfolding of the prompt energy measurements into antineutrino energy. This \(\bar{\nu}_e\) energy spectrum is provided to the community, and an excess of events relative to the Huber model is found in the 5-6 MeV region. When a Gaussian bump is fitted to the excess, the data-model \(\chi^2\) value is improved, corresponding to a \(2.4\sigma\) significance.
The relative transmissivities of several commonly used ultrasonic coupling agents were measured to determine if there were significant differences in their effectiveness. Coupling media were ...evaluated in thin films to simulate clinical use. In order to minimize experimental error in this determination, transmitted energy was measured in the far field of the sonating transducer; the receiving transducer was angled slightly to minimize standing waves; and the sonating chamber was made as anechoic as possible. It was found that there is no practical difference in the transmissivities of the common coupling agents, except that hydrocortisone ointments and creams had lower transmissivities, probably due to microscopically entrapped air. When used as a thin film, absorption of ultrasound in the media was insignificant, and variation in transducer pressure was found to cause differences in energy transmitted greater than those found between the common coupling media. Consequently, it was concluded that coupling media can be chosen primarily on the basis of cost and convenience.
This report highlights two different types of cross-talk in the photodetectors of the miniTimeCube neutrino experiment. The miniTimeCube detector has 24 \(8 \times 8\)-anode Photonis MCP-PMTs ...Planacon XP85012, totalling 1536 individual pixels viewing the 2-liter cube of plastic scintillator.
