Cosmogenic activation of xenon and copper

Rare event search experiments using liquid xenon as target and detection medium require ultra-low background levels to fully exploit their physics potential. Cosmic ray induced activation of the detector components and, even more importantly, of the xenon itself during production, transportation and storage at the Earth's surface, might result in the production of radioactive isotopes with long half-lives, with a possible impact on the expected background. We present the first dedicated study on the cosmogenic activation of xenon after 345 days of exposure to cosmic rays at the Jungfraujoch research station at 3470m above sea level, complemented by a study of copper which has been activated simultaneously. We have directly observed the production of 7Be, 101Rh, 125Sb, 126I and 127Xe in xenon, out of which only 125Sb could potentially lead to background for a multi-ton scale dark matter search. The production rates for five out of eight studied radioactive isotopes in copper are in agreement with the only existing dedicated activation measurement, while we observe lower rates for the remaining ones. The specific saturation activities for both samples are also compared to predictions obtained with commonly used software packages, where we observe some underpredictions, especially for xenon activation.

Was mich zur Hochschule führte

K. Vollers

Das unsterbliche Blut : Anmerkungen zu Georg Fink: "Mich hungert ..." (erschienen bei Bruno Cassirer, Berlin 1930]

Kurt Münzer

Psalm 126 : gewidmet Herrn Dr. Heinrich Loewe, der mich zum Zionismus geführt hat

Dolorosa

Fort Richardson Ordnance Detonations and the Harbor Porpoise: A Case Study in Marine Mammal Bioacoustics

Hearing is extremely important for cetaceans because it is their “principal sense” (Weilgart, 2007) thus the harbor porpoise and other marine animals are highly dependent on sound for survival. This is why we should care about the impact of noise on animals like the harbor porpoise. Since sound travels so well in water, an explosion, sonar, boat noise, etc. can affect a very large area and thus many different species of marine mammals. Although military actions such as low frequency sonar have made recent news, noise has been affecting cetaceans, especially beaked whales, since at least 1991 (Weilgart, 2007). This study is an investigation of the possible impacts of artillery detonated on land on harbor porpoise hearing and covers some of the history of Fort Richardson, the legal and historical aspects and history of this type of concern, the science and physics of sound, marine mammal hearing and general biology of the harbor porpoise. Data were collected at the Fort Richardson Army base during June of 2007 by researchers from the University of Connecticut and the University of Rhode Island and will be used to determine the possible impacts that these detonations could have on the harbor porpoise.

[Ich will dich ganz zart mich lehren...]

Else Lasker-Schüler

Kurtze Vertheidigung derer in dem Büchlein, Michael mache dich auf zum Streit, befindlichen Worte: Man fragt mich um die Frauen Liebe, ...

Erscheinungsjahr ermittelt

Di Sheine Americanerin. Der Hersher Is Der Man. Weiber Macht Mich Far President. Duet, Menner Lerent Eiere Weiber

B.Thomashevsky

Ein schön new lied : gena[nn]t Des himmels strassen heyß ich, wiltu wo wandel mich, ... In der weiß, Wolauff gut gesell von hinnen, ...

[Wolff Gernolt ... hat er das lied gedicht]

Wie ich mich zum Aquarium-Liebhaber ausbildete

Von G. Haberlé