Design of the Setup for the AnaBHEL Experiment

International audienceThe AnaBHEL experiment aims to detect the analog Hawking radiation emitted by an accelerated relativistic plasma mirror for which the effective event horizon is analogous to that of a black hole, thanks to the equivalence principle. This radiation is composed of a few Hawking photons emitted simultaneously in the infrared band and the ‘partner photons’ in the ultraviolet band. The former is emitted in the opposite direction of the mirror propagation and is redshifted in the laboratory frame. In the AnaBHEL scheme, high-intensity petawatt laser pulses, will be used to produce the relativistic accelerated plasma mirrors from a helium gas jet. Infrared and ultraviolet photons generated by the mirrors will be detected by dedicated superconducting nanowire single-photon detectors (SNSPDs) at very low temperature and by multichannel plates at room temperature, respectively. Details of the setup design are discussed

Development of Total Decay Energy Spectrometry of α-Emitting Radionuclides Using Metallic Magnetic Calorimeters

International audienceTotal decay energy spectrometry with cryogenic detectors is a promising technique for radionuclide analysis of α-emitting nuclides. The radioactive sample is embedded in the detector absorber, and the total decay energy for each disintegration is measured as a temperature elevation. We are developing this technique with metallic magnetic calorimeters (MMCs). The main condition of this technique is a detection efficiency close to unity. However, some α-emitting nuclides emit intense γ-rays that can partially escape from the absorber. So a feasibility study for several nuclides has been carried out based on Monte Carlo simulations of the detection efficiency and numerical calculations of the expected energy resolution to identify the radionuclides that can potentially be measured. Furthermore, an MMC prototype has been built and tested. The total decay energy spectrum of Po-210 was measured, and a FWHM energy resolution of 1.25 keV at 5.4 MeV was obtained and a Gaussian width at half maximum of 0.827 (5) keV. The baseline FWHM energy resolution is 207 eV, consistent with the resolution obtained on low-energy L X-rays in the same spectrum at 14 keV

Preparation of Drop-Deposited Sources in 4π Absorbers for Total Decay Energy Spectrometry

International audienceTotal decay energy spectrometry (Q spectrometry) with cryogenic detectors is a promising technique for analysis of α-emitting actinides. However, this technique is very sensitive to the quality of the source preparation due to the absorption of the nuclear recoil energy in the source material. Drop deposition of the radioactive solution without care produces spectra with unpredictable peak shapes. In order to keep the simplicity of the drop deposition technique, we study the deposition of solution on latex nanoparticles or in nanoporous gold (NPAu) to improve the source quality. 4π absorbers were fabricated and tested using these two techniques. The absorbers contained a mixture of Pu isotopes. From the best Q spectrum, the composition of Pu isotopes and other actinides was measured and it is in very good agreement with the reference values given by alpha and mass spectrometry

High-Resistivity Transition-Edge Sensor Modeling and Expected Performances

International audienceHigh spectral resolution detectors based on low-resistivity transition-edge sensors (TES) are being developed for future X-ray spatial observatories, but difficulties (cryogenics limitations) are to be expected in next generation’s detectors with even more pixels. A new technology, the high-resistivity TES (HRTES), is likely to offer similar performance to existing TES when associated to an active electrothermal feedback, adding the possibility of moving the readout electronics to a 2.5 K stage of the cryocooler. This work aims to investigate HRTES by making a precise model of the device, comparing it to experimental measurements, and deducing its performance potential

Background reduction of a spherical gaseous detector

International audienceThe Spherical gaseous detector (or Spherical Proportional Counter, SPC) is a novel type of detector. It consists of a large spherical volume filled with gas, using a single detection readout channel. The detector allows 100 % detection efficiency. SEDINE is a low background version of SPC installed at the Laboratoire Souterrain de Modane (LSM) underground laboratory (4800 m.w.e) looking for rare events at very low energy threshold, below 100 eV. This work presents the details on the chemical cleaning to reduce internal 210Pbsurface contamination on the copper vessel and the external radon reduction achieved via circulation of pure air inside anti-radon tent. It will be also show the radon measurement of pure gases (Ar, N, Ne, etc) which are used in the underground laboratory for the low background experiments