The low-energy monochromatic neutron emission from an Y-88/Be source can be exploited to mimic the few keVnr nuclear recoils expected from low-mass Weakly Interacting Massive Particles (WIMPs) and coherent scattering of neutrinos off nuclei. Using this source, a ~<10% quenching factor is measured for sodium recoils below 24 keVnr in NaI[Tl]. This is considerably smaller than the 30% typically adopted in the interpretation of the DAMA/LIBRA dark matter experiment, resulting in a marked increase of its tension with other searches, under the standard set of phenomenological assumptions. The method is illustrated for other target materials (superheated and noble liquids).
A calibration procedure is proposed for the ITER Radial Neutron Camera. No in-vessel calibration using external neutron sources is required: instead, it is proposed to rely on embedded sources, reference ITER pulses and cross-calibration with ITER fission chambers and activation system coupled to Monte Carlo simulations of radiation transport for the validation of the RNC calibration and for its tracking during ITER lifetime.
The conditions of tests and calibrations described in the article E.E Kading et al. [Phys. Rev. Res. 2, 023279 (2020)] show striking flaws. The interpretation and extraction of quantitative results from this experiment are considered unreliable. All results of cross sections based on the results described in this article must be disregarded.
We present characterization results of a neutron Anger camera based on a lithium-6 loaded cerium activated silicate glass scintillator (33.3 x 33.3 x 1 mm3) and an array of 64 silicon photomultipliers. Reconstruction of the scintillation events is performed with a statistical method, implemented on a graphics processing unit (GPU). We demonstrate that the light response model of the detector can be obtained from flood irradiation calibration data using an unsupervised iterative procedure. The useful field of view is 28 x 28 mm2. The spatial resolution measured at 2.5 A neutron beam is better t…
In the present article we describe the calibration measurements of the compact neutron spectrometer at certified PTB neutron source. The spectrometer is based on two diamond detectors enclosing the Li-6 neutron converter. The incident neutron energy is measured through the sum of energies of the two conversion reaction products: t and alpha. The prototype used in this work was based on two 4x4 mm2, 100 um thick single crystal CVD commercial diamond plates. The measurements were performed in the fission spectrum domain at five different neutron energies varying from 0.3 up to 2 MeV. The obtaine…
The measurement of the neutron capture cross-section as a function of energy in the thermal range requires a precise knowledge of the absolute neutron flux. In this paper a new method of calibrating a thermal neutron beam using the controlled activation of sodium is described. The method is applied to the FP-14 Time Of Flight neutron beam line at the Los Alamos Neutron Science Center to calibrate the beam to a precision of $\pm5$%.
The feasibility of an ultra-low energy nuclear-recoil measurement in liquid xenon using neutron capture is investigated for a small (sub-kilogram) liquid xenon detector that is optimized for a high scintillation gain, and a pulsed neutron source. The measurement uses the recoil energies imparted to xenon nuclei during the de-excitation process following neutron capture, where promptly emitted $γ$ cascades can provide the nuclei with up to $0.3$ keV$_\text{nr}$ of recoil energy due to conservation of momentum. A successful calibration of scintillation photon and ionization electron yields below…
Bolometric calibration of a superfluid $^3$He detector for Dark Matter search: direct measurement of the scintillated energy fraction for neutron, electron and muon events
Beta-delayed neutron emission plays a fundamental role in the explosive nucleosynthesis of elements heavier than iron by the rapid neutron capture (r-process). The most ambitious project related to beta-delayed neutron detection of very exotic nuclei is carried out by the BRIKEN collaboration at RIKEN Nishima Center. In this work, a brief description of the BRIKEN project is presented. A methodology for the precise characterization of the BRIKEN neutron counter efficiency, for fast neutrons, using an uncalibrated 252Cf neutron source is described. The method relies on the well-known neutron mu…
The demand for new thermal neutron detectors as an alternative to 3He tubes in research, industrial, safety and homeland security applications, is growing. These needs have triggered research and development activities about new generations of thermal neutron detectors, characterized by reasonable efficiency and gamma rejection comparable to 3He tubes. In this paper we show the state of the art of a promising low-cost technique, based on commercial solid state silicon detectors coupled with thin neutron converter layers of 6LiF deposited onto carbon fiber substrates. A few configurations were …
The DArk Matter Particle Explorer (DAMPE), one of the four space-based scientific missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences, has been successfully launched on Dec. 17th 2015 from Jiuquan launch center. One of the most important scientific goals of DAMPE is to search for the evidence of dark matter indirectly by measuring the spectrum of high energy cosmic-ray electrons. The neutron detector, one of the four sub-payloads of DAMPE, is designed to distinguish high energy electrons from hadron background by measuring the seco…
Design Studies Of A Pulsed Quasimonoenergetic 2-keV Neutron Source For Calibration Of Low Threshold Dark Matter Detectors
University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；University of California Berkeley（加州大学伯克利分校）；High Energy Accelerator Research Organization (KEK)（高能加速器研究机构（KEK））；Florida State University（佛罗里达州立大学）；National High Magnetic Field Laboratory（国家高磁场实验室）
A comparison of the neutron detection efficiency and response characteristics of two pixelated PSD-capable organic scintillator detectors with different photo-detection readout methods
Neutron capture-induced nuclear recoils have emerged as an important tool for detector calibrations in direct dark matter detection and coherent elastic neutrino-nucleus scattering (CE$ν$NS). $\texttt{nrCascadeSim}$ is a command-line tool for generating simulation data for energy deposits resulting from neutron capture on pure materials. Presently, silicon, germanium, neon, and argon are supported. While the software was developed for solid state detector calibration, it can be used for any application which requires simulated neutron capture-induced nuclear recoil data.
The Optically Segmented Single Volume Scatter Camera (OS-SVSC) aims to image neutron sources for non-proliferation applications using the kinematic reconstruction of elastic double-scatter events. Our prototype system consists of 64 EJ-204 organic plastic scintillator bars, each measuring 5 mm $\times$ 5 mm $\times$ 200 mm and individually wrapped in Teflon tape. The scintillator array is optically coupled to two silicon photomultiplier ArrayJ-60035 64P-PCB arrays, each comprised of 64 individual 6 $\times$ 6 mm J-Series sensors arranged in an 8 $\times$ 8 array. We detail our calibration effo…
The development of low-threshold detectors for the study of coherent elastic neutrino-nucleus scattering and for the search for light dark matter necessitates methods of low-energy calibration. We suggest this can be provided by the nuclear recoils resulting from the $γ$ emission following thermal neutron capture. In particular, several MeV-scale single-$γ$ transitions induce well-defined nuclear recoil peaks in the 100 eV range. Using the FIFRELIN code, complete schemes of $γ$-cascades for various isotopes can be predicted with high accuracy to determine the continuous background of nuclear r…
Experiments searching for neutrinoless double beta decay ($0νββ$) require precise energy calibration and extremely low backgrounds. One of the most popular isotopes for $0νββ$ experiments is $^{136}$Xe. In support of these experiments, the neutron inelastic scattering properties of this isotope have been measured at the GErmanium Array for Neutron Induced Excitations (GEANIE) at the Los Alamos Neutron Science Center. Time-of-flight techniques are utilized with high-purity germanium detectors to search for inelastic scattering $γ$ rays for neutron energies between 0.7 and 100 MeV. Limits are se…
Sub-keV energy calibration of CONUS+ via 71Ge M-shell neutron activation
Max-Planck-Institut für Kernphysik（马克斯·普朗克核物理研究所）；Karlsruher Institut für Technologie (KIT)（卡尔斯鲁厄理工学院）；Marietta-Blau-Institut für Teilchenphysik der ÖAW（奥地利科学院玛丽埃塔·布劳粒子物理研究所）；Mirion Technologies (Canberra) GmbH（米尔恩技术（堪培拉）有限公司）
Evaluation of a method for time-of-flight, wavelength and distance calibration for neutron scattering instruments by means of a mini-chopper and standard neutron monitors
The Backward Angle Neutron Detector (BAND) of CLAS12 detects neutrons emitted at backward angles of $155^\circ$ to $175^\circ$, with momenta between $200$ and $600$ MeV/c. It is positioned 3 meters upstream of the target, consists of $18$ rows and $5$ layers of $7.2$ cm by $7.2$ cm scintillator bars, and read out on both ends by PMTs to measure time and energy deposition in the scintillator layers. Between the target and BAND there is a 2 cm thick lead wall followed by a 2 cm veto layer to suppress gammas and reject charged particles. This paper discusses the component-selection tests and the …
Preparation and measurement of an $\rm ^{37}$Ar source for liquid xenon detector calibration
School of Physics, Beihang University（北京航空航天大学物理学院）；Department of Physics&Center for High Energy Physics, Tsinghua University（清华大学物理系及高能物理中心）；Northwest Institute of Nuclear Technology（中核西北核技术研究所）；School of Physics, Sun Yat-Sen University（中山大学物理学院）
Detector calibration is very important for the long-term operation. For the purposes of simple and precise calibration, we developed a new portable calibration source using UVLED to calibrate the fluorescence detector of the Telescope Array experiment (TA). The UVLED is light (less than 1 kg) and its setup is quick and easy. Therefore, a single source will be used instead of the calibration sources that TA currently uses. The UVLED emits 369 nm wavelength and ~70 pJ of photons which are calibrated with 5% accuracy us-ing photo-diode. It has a particular unit, which is an internal heater, to ke…
In the search for a monochromatic peak as the signature of neutrinoless double beta decay an excellent energy resolution and an ultra-low background around the $Q$-value of the decay are essential. The LEGEND-200 experiment performs such a search with high-purity germanium detectors enriched in $^{76}$Ge immersed in liquid argon. To determine and monitor the stability of the energy scale and resolution of the germanium diodes, custom-made, low-neutron emission $^{228}$Th sources are regularly deployed in the vicinity of the crystals. Here we describe the production process of the 17 sources av…
We derive the full expression for the shape of the charge spectrum that results from the illumination of a photo-multiplier tube. The derivation is for low intensity illumination with constant gain, a common condition for most nuclear and particle physics applications. Under these conditions, it is shown that an analytic expression can be formulated that describes details of the spectrum including the pedestal and dark noise with excellent fidelity to allow statistical fits to data. The derivation and full formula using either Gaussian or Poisson models for gain, and its limiting forms under v…
The calibration of the ICARUS photo-detection system is based on a low power laser diode at 405 nm. Laser pulses arrive to one optical switch and then are sent to 36 UHV flanges, by 20 meters long optical patches. Light is then delivered to the ten PMTs connected to a single flange, by 7m long injection optical patches. Extensive tests of the used components and care in the design of the optical system have guaranteed to each PMT a sizeable calibration signal with minimal distortion, with respect to the original one. Gain equalization of PMTs has reached a 1 per cent resolution. In this proced…
The procedure for the energy calibration of the high granularity electromagnetic calorimeter PHOS of the ALICE experiment is presented. The methods used to perform the relative gain calibration, to evaluate the geometrical alignment and the corresponding correction of the absolute energy scale, to obtain the nonlinearity correction coefficients and finally, to calculate the time-dependent calibration corrections, are discussed and illustrated by the PHOS performance in proton-proton (pp) collisions at $\sqrt{s}$ = 13 TeV. After applying all corrections, the achieved mass resolutions for $π^0$ …
The results of the extended quadrahedral NaI(Tl) spectrometer`s calibration by cosmic muons are presented. The signal amplitude and energy resolution of the spectrometer have complex dependencies on the voltage at the photomultiplier and the entry point of the particle into the spectrometer in the transverse direction. When the voltage across the photomultiplier divider photomultiplier is U = 1150 V the homogeneous signals area is observed at about 90% of the spectrometer length, the energy resolution is about 7%.
