Seasnal variation in the environmental background level of cosmic-ray-produced 22Na at Fukui City, Japan

We present the characteristics and performance of a demonstration experiment devoted to the observation of ultra high-energy cosmic ray extensive air showers using a radiodetection technique. In a first step, one antenna narrowed band filtered acting as trigger, with a 4σ threshold above sky background-level, was used to tag any radio transient in coincidence on the antenna array. Recently, the addition of 4 particle detectors has allowed us to observe cosmic ray events in coincidence with antennas.

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Feasibility Study of a New Cherenkov Detector for Improving Volcano Muography

Sensors ◽

10.3390/s19051183 ◽

2019 ◽

Vol 19 (5) ◽

pp. 1183 ◽

Cited By ~ 5

Author(s):

Domenico Lo Presti ◽

Giuseppe Gallo ◽

Danilo Bonanno ◽

Daniele Bongiovanni ◽

Fabio Longhitano ◽

...

Keyword(s):

Feasibility Study ◽

Background Noise ◽

Cherenkov Radiation ◽

Background Level ◽

Cosmic Ray ◽

Muon Flux ◽

Arrival Direction ◽

High Background ◽

X Ray ◽

Preliminary Study

Muography is an expanding technique for internal structure investigation of large volume object, such as pyramids, volcanoes and also underground cavities. It is based on the attenuation of muon flux through the target in a way similar to the attenuation of X-ray flux through the human body for standard radiography. Muon imaging have to face with high background level, especially compared with the tiny near horizontal muon flux. In this paper the authors propose an innovative technique based on the measurement of Cherenkov radiation by Silicon photo-multipliers arrays to be integrated in a standard telescope for muography applications. Its feasibility study was accomplished by means of Geant4 simulations for the measurement of the directionality of cosmic-ray muons. This technique could be particularly useful for the suppression of background noise due to back-scattered particles whose incoming direction is likely to be wrongly reconstructed. The results obtained during the validation study of the technique principle confirm the ability to distinguish the arrival direction of muons with an efficiency higher than 98% above 1 GeV. In addition, a preliminary study on the tracking performance of the presented technique was introduced.

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Environmental Assessment in the Pre-launch Phase of Hayabusa2 for Safety Declaration of Returned Samples From Asteroid (162173) Ryugu: Background Monitoring of Possible Contaminants During Development of the Sampler System

10.21203/rs.3.rs-1119888/v1 ◽

2021 ◽

Author(s):

Kanako Sakamoto ◽

Yoshinori Takano ◽

Hirotaka Sawada ◽

Ryuji Okazaki ◽

Takaaki Noguchi ◽

...

Keyword(s):

Background Level ◽

Major Elements ◽

Organic Content ◽

Inorganic Analysis ◽

Sample Analysis ◽

Environmental Assessments ◽

Pristine Sample ◽

Launch Site ◽

Environmental Background ◽

Static Monitoring

Abstract We report the ground-based environmental assessments during development of the sampler system until the launch of the Hayabusa2 spacecraft. We conducted static monitoring of potential contaminants to assess the environmental cleanliness during (1) laboratory work throughout the development and manufacturing of the sampler devices, (2) installation of the sampler system on the spacecraft, and (3) transportation to the launch site at the JAXA’s Tanegashima Space Center. Major elements and ions detected in our inorganic analysis were sodium (Na), potassium (K), and ionized chloride (Cl–); those were positively correlated with the total organic content and with exposure duration in the range from 101 to 103 nanogram per monitor coupon within a ~30 mm-diameter scale. We confirmed that deposits on the coupon were totally less than the microgram-scale order during manufacturing, installation, and transportation in the pre-launch phase. The present assessment yields a nominal safety declaration for sample analysis of the pristine sample (>5 g) returned from asteroid (162173) Ryugu combined with a highly clean environmental background level. We expect that the Hayabusa2-returned sample from Ryugu without severe and/or unknown contamination will allow us to provide native profiles recorded in the carbonaceous asteroid history.

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