No Arabic abstract
An active device for radon detection in the air was developed. The monitor operates in pulse counting mode for real-time continuous measurements. The presented prototype has a relatively simple design made of low-price and easy to acquire components which made it possible to develop an inexpensive device. The device used as a sensor, the SLCD-61N5 Si-PIN planar photodiode, which has an area of 9.67x9.67 mm2, is sensitive to alpha particles. An Arduino Uno microcontroller was used as a data acquisition system. Signals were observed when placing an 241Am or 226Ra source near the sensor. The sensors sensitivity has small bias dependency and the device can operate even at modest voltage. As a result of a one-month test in a radon-rich atmosphere, a positive high correlation (Pearsons r equal to 0.977) was obtained between our prototype and a Geiger-Muller detector.
We report on the design and the expected performance of a low cost hybrid detection system suitable for operation as an autonomous unit in strong electromagnetic noise environments. The system consists of three particle detectors (scintillator modules) and one or more RF antennas. The particle detector units are used to detect air showers and to supply the trigger to the RF Data acquisition electronics. The hardware of the detector as well as the expected performance in detecting and reconstructing the angular direction for the shower axis is presented. Calibration data are used to trim the simulation parameters and to investigate the response to high energy ($E>10^{15} eV$) extensive air showers.
Aiming at the observation of cosmic-ray chemical composition at the knee energy region, we have been developinga new type air-shower core detector (YAC, Yangbajing Air shower Core detector array) to be set up at Yangbajing (90.522$^circ$ E, 30.102$^circ$ N, 4300 m above sea level, atmospheric depth: 606 g/m$^2$) in Tibet, China. YAC works together with the Tibet air-shower array (Tibet-III) and an underground water cherenkov muon detector array (MD) as a hybrid experiment. Each YAC detector unit consists of lead plates of 3.5 cm thick and a scintillation counter which detects the burst size induced by high energy particles in the air-shower cores. The burst size can be measured from 1 MIP (Minimum Ionization Particle) to $10^{6}$ MIPs. The first phase of this experiment, named YAC-I, consists of 16 YAC detectors each having the size 40 cm $times$ 50 cm and distributing in a grid with an effective area of 10 m$^{2}$. YAC-I is used to check hadronic interaction models. The second phase of the experiment, called YAC-II, consists of 124 YAC detectors with coverage about 500 m$^2$. The inner 100 detectors of 80 cm $times $ 50 cm each are deployed in a 10 $times$ 10 matrix from with a 1.9 m separation and the outer 24 detectors of 100 cm $times$ 50 cm each are distributed around them to reject non-core events whose shower cores are far from the YAC-II array. YAC-II is used to study the primary cosmic-ray composition, in particular, to obtain the energy spectra of proton, helium and iron nuclei between 5$times$$10^{13}$ eV and $10^{16}$ eV covering the knee and also being connected with direct observations at energies around 100 TeV. We present the design and performance of YAC-II in this paper.
We present our latest ASIC, which is used for the readout of Cadmium Telluride double-sided strip detectors (CdTe DSDs) and high spectroscopic imaging. It is implemented in a 0.35 um CMOS technology (X-Fab XH035), consists of 64 readout channels, and has a function that performs simultaneous AD conversion for each channel. The equivalent noise charge of 54.9 e- +/- 11.3 e- (rms) is measured without connecting the ASIC to any detectors. From the spectroscopy measurements using a CdTe single-sided strip detector, the energy resolution of 1.12 keV (FWHM) is obtained at 13.9 keV, and photons within the energy from 6.4 keV to 122.1 keV are detected. Based on the experimental results, we propose a new low-noise readout architecture making use of a slew-rate limited mode at the shaper followed by a peak detector circuit.
Pacific Northwest National Laboratory has recently opened a shallow underground laboratory intended for measurement of low-concentration levels of radioactive isotopes in samples collected from the environment. The development of a low-background liquid scintillation counter is currently underway to further augment the measurement capabilities within this underground laboratory. Liquid scintillation counting is especially useful for measuring charged particle (e.g., $beta$, $alpha$) emitting isotopes with no (or very weak) gamma-ray yields. The combination of high-efficiency detection of charged particle emission in a liquid scintillation cocktail coupled with the low-background environment of an appropriately-designed shield located in a clean underground laboratory provides the opportunity for increased-sensitivity measurements of a range of isotopes. To take advantage of the 35 meters-water-equivalent overburden of the underground laboratory, a series of simulations have evaluated the scintillation counters shield design requirements to assess the possible background rate achievable. This report presents the design and background evaluation for a shallow underground, low background liquid scintillation counter design for sample measurements.
Argon-37 is an environmental signature of an underground nuclear explosion. Producing and quantifying low-level Ar-37 standards is an important step in the development of sensitive field measurement instruments. This paper describes progress at Pacific Northwest National Laboratory in developing a process to generate and quantify low-level Ar-37 standards, which can be used to calibrate sensitive field systems at activities consistent with soil background levels. This paper presents a discussion of the measurement analysis, along with assumptions and uncertainty estimates.