This proceeding presents the CONRAD high-purity germanium spectrometer with a large diode (2.2 kg mass) employing electrical cryocooling. The detector is an ideal tool to characterize background up ...to high energies of ∼12 MeV. The detector itself exhibits a high level of radiopurity. Due to the cryocooling the detector is flexible and of low maintenance effort. It can be deployed for example at nuclear reactors for site characterization such as for the CONUS experiment, which is looking for coherent elastic neutrino nucleus scattering.
•Radiopure Germanium spectrometer with large detection efficiency at high energies.•Low maintenance and high flexibility due to electrical cryocooling.•Site characterization of gamma and neutron background at a nuclear power plant.•Tungsten as a potential alternative for lead as high-density shield material.
This proceeding presents the decomposition of the background spectra of the four screening detectors GeMPI 1 - 4 at the Gran Sasso Underground Laboratory (LNGS) using Monte Carlo simulations in the ...Geant4-based framework MaGe. A detailed understanding of the composition of the background spectra was achieved, allowing for the proposal of two new shield designs for future GeMPI-like detectors and enabling a reduction of the integrated background count rate to 15 counts/d/kg in the interval 40, 2700 keV.
•GeMPI detectors are the most sensitive Germanium spectrometers in the world.•Background spectrum of the GeMPI detectors has been fully decomposed and understood through Monte Carlo simulations.•Pb210 in the lead shield of the detectors is the most prominent source of background.•Two new shield designs are proposed to reduce the background level and increase the sensitivity of the GeMPI detectors.
Jesenice-A new meteorite fall from Slovenia BISCHOFF, Addi; JERSEK, Miha; GRAU, Thomas ...
Meteoritics & planetary science,
June 2011, Letnik:
46, Številka:
6
Journal Article
Recenzirano
– On April 9, 2009, at 3:00 CEST, a very bright fireball appeared over Carinthia and the Karavanke Mountains. The meteoroid entered the atmosphere at a very steep angle and disintegrated into a large ...number of objects. Two main objects were seen as separate fireballs up to an altitude of approximately 5 km, and witnesses reported loud explosions. Three stones were found with a total weight of approximately 3.611 kg. The measured activity of short‐lived cosmogenic radionuclides clearly indicates that two specimens result from a very recent meteorite fall. All cosmogenic radionuclide concentrations suggest a rather small preatmospheric radius of <20 cm; a nominal cosmic‐ray exposure age based on 21Ne is approximately 4 Ma, but the noble gas and radionuclide results in combination indicate a complex irradiation. Jesenice is a highly recrystallized rock with only a few relic chondrules visible in hand specimen and thin section. The texture, the large grain size of plagioclase, and the homogeneous compositions of olivines and pyroxenes clearly indicate that Jesenice is a L6 chondrite. The bulk composition of Jesenice is very close to the published average element concentration for L ordinary chondrites. The chondrite is weakly shocked (S3) as indicated by the undulatory extinction in olivine and plagioclase and the presence of planar fractures in olivine. Being weakly shocked and with gas retention ages of >1.7 Ga (4He) and approximately 4.3 Ga (40Ar), Jesenice seems not to have been strongly affected by the catastrophic disruption of the L‐chondrite parent body approximately 500 Ma ago.
We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer Veto), recently built and now operated at the shallow underground laboratory ...of the Max-Planck-Institut f\"ur Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of <100 {\mu}Bq/kg for primordial radionuclides from U and Th in typical {\gamma} ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites.
The Mbale meteorite shower Jenniskens, Peter; Betlem, Hans; Betlem, Jan ...
Meteoritics,
March 1994, Letnik:
29, Številka:
2
Journal Article
Recenzirano
— On 1992 August 14 at 12:40 UTC, an ordinary chondrite of type L5/6 entered the atmosphere over Mbale, Uganda, broke up, and caused a strewn field of size 3 × 7 km. Shortly after the fall, an ...expedition gathered eye witness accounts and located the position of 48 impacts of masses between 0.1 g and 27.4 kg. Short‐lived radionuclide data were measured for two specimens, one of which was only 12 days after the fall. Subsequent recoveries of fragements has resulted in a total of 863 mass estimates by 1993 October. The surfaces of all fragments contain fusion crust. The meteorite shower caused some minor inconveniences. Most remarkably, a young boy was hit on the head by a small specimen.
The data are interpreted as to indicate that the meteorite had an initial mass between 400–1000 kg (most likely ∼1000 kg) and approached Mbale from Az = 185 ± 15, H = 55 ± 15, and V∞ = 13.5 ± 1.5/s. Orbital elements are given. Fragmentation of the initial mass started probably above 25 km altitude, but the final catastrophic breakup occurred at an altitude of 10–14 km. An estimated 190 ± 40 kg reached the Earth's surface minutes after the final breakup of which 150 kg of material has been recovered.
GENIUS is a proposal for a large volume detector to search for rare events.
An array of 40-400 'naked' HPGe detectors will be operated in a tank filled
with ultra-pure liquid nitrogen. After a ...description of performed technical
studies of detector operation in liquid nitrogen and of Monte Carlo simulations
of expected background components, the potential of GENIUS for detecting WIMP
dark matter, the neutrinoless double beta decay in 76-Ge and low-energy solar
neutrinos is discussed.
GENIUS is a proposal for a large volume detector to search for rare events. An array of 40-400 'naked' HPGe detectors will be operated in a tank filled with ultra-pure liquid nitrogen. After a ...description of performed technical studies of detector operation in liquid nitrogen and of Monte Carlo simulations of expected background components, the potential of GENIUS for detecting WIMP dark matter, the neutrinoless double beta decay in 76-Ge and low-energy solar neutrinos is discussed.
Purpose
Chronic obstructive pulmonary disease (COPD) is associated with elevated sympathetic nerve activity, which is probably linked to an increased cardiovascular risk, and may contribute to muscle ...dysfunction by heightened muscle vasoconstrictor drive. We hypothesized that resistive unloading of respiratory muscles by intermittent non-invasive ventilation (NIV) reduces sympathetic tone at rest and during subsequent handgrip exercise in patients with COPD.
Methods
Muscle sympathetic nerve activity (MSNA) in the peroneal nerve, heart rate, blood pressure, CO
2
, and SpO
2
were continuously recorded in 5 COPD patients with intermittent NIV and 11 control COPD patients without NIV. Static and dynamic handgrip exercises were performed before and after NIV.
Results
At baseline, heart rate-adjusted MSNA (bursts/100 heart beats) did not differ between groups. NIV did not significantly affect MSNA levels at rest. However, during handgrip exercises directly following NIV, MSNA was lower than before, which was significant for dynamic handgrip (67.00 ± 3.70 vs. 62.13 ± 4.50 bursts/100 heart beats;
p
= 0.035 in paired
t
test). In contrast, MSNA (non-significantly) increased in the control group during repeated dynamic or static handgrip. During dynamic handgrip, tCO
2
was lower after NIV than before (change by −5.04 ± 0.68 mmHg vs. −0.53 ± 0.64 in the control group;
p
= 0.021), while systolic and diastolic blood pressure did not change significantly.
Conclusions
NIV reduces sympathetic activation during subsequent dynamic handgrip exercise and thereby may elicit positive effects on the cardiovascular system as well as on muscle function in patients with COPD.
Exercise intolerance, skeletal muscle dysfunction, and reduced daily activity are central in COPD patients and closely related to quality of life and prognosis. Studies assessing muscle exercise have ...revealed an increase in sympathetic outflow as a link to muscle hypoperfusion and exercise limitation. Our primary hypothesis was that muscle sympathetic nerve activity (MSNA) correlates with exercise limitation in COPD.
MSNA was evaluated at rest and during dynamic or static handgrip exercise. Additionally, we assessed heart rate, blood pressure, CO2 tension, oxygen saturation (SpO2), and breathing frequency. Ergospirometry was performed to evaluate exercise capacity.
We assessed MSNA of 14 COPD patients and 8 controls. In patients, MSNA was negatively correlated with peak oxygen uptake (VO
2
% pred) (r = −0.597; p = 0.040). During dynamic or static handgrip exercise, patients exhibited a significant increase in MSNA, which was not observed in the control group. The increase in MSNA during dynamic handgrip was highly negatively correlated with peak exercise capacity in Watts (w) and peak oxygen uptake (VO2/kg) (r = −0.853; p = 0.002 and r = −0.881; p = 0.002, respectively).
Our study reveals an association between increased MSNA and limited exercise capacity in patients with COPD. Furthermore, we found an increased sympathetic response to moderate physical exercise (handgrip), which may contribute to exercise intolerance in COPD.
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