On the detection of ²²²Rn with miniaturized proportional counters: background, sensitivity studies and results for XENON1T

The radioactive isotope 222Rn is one of the most crucial intrinsic background sources for experiments dealing with a low event rate. Being a noble gas, it permanently emanates from almost all materials that are used in the detector. Its decay or the successive decays of its daughter isotopes can mimic the searched-for signal. This thesis was carried out in the context of the experiment XENON1T which aims at directly detecting weakly interacting massive particles (WIMPs), that could be a candidate for the postulated dark matter in the Universe. An extensive measurement campaign was performed in order to determine the 222Rn emanation rate of the detector components that will be in contact with the liquid xenon target. The individual results and an estimation of the detector’s overall emanation rate are reported in this work for the first time. For a further improvement of the detection of 222Rn with proportional counters, the sensitivity of the two counting gases ArCH4 and XeCH4 was studied in connection with different background shieldings. A direct comparison of the two counting gases makes an energy calibration necessary, the one for ArCH4 was improved in the context of this work

Radon Induced Background in the XENON1T Dark Matter Search Experiment and Studies on Xenon Purity in the HeXe System

The XENON1T experiment is aiming for the direct detection of dark matter in the form of weakly interacting massive particles (WIMPs) scattering off xenon nuclei. Detecting these rarely-interacting particles requires an unprecedented low background level. In XENON1T, the noble gas 222Rn induces the dominant background, either as electronic recoil (ER) background admixed in the liquid xenon (LXe) volume or as surface background on the Time- Projection-Chamber’s (TPC) wall. In the first part of this thesis, we constrain the amount of 222Rn induced ER background during the complete run-time of the experiment. We furthermore survey the considerable 222Rn reduction during the XENON1T operation, resulting in a final activity concentration of (4:5 ± 0:1) μBq=kg, the lowest one ever achieved in a LXe dark matter experiment. Conclusions drawn are relevant not only for the interpretation of the background level in XENON1T, but also for the next-generation experiment XENONnT. The 222Rn induced surface background can be removed from the PTFE (Polytetrafluoroethylene) wall of the TPC by dedicated surface cleaning methods based on 32% HNO3. In the second part of this work, we constructed a small-scale LXe TPC, the HeXe set-up, to test for the first time if a PTFE surface cleaning based on 32%HNO3 degrades the xenon purity and the performance of a TPC. No degradation of the xenon purity is observed within the system’s sensitivity, indicating that 32%HNO3 is a promising candidate for PTFE surface cleaning in LXe TPCs. Our result lays the groundwork for future research towards confirming that the treatment is applicable in large-scale LXe detectors

The Growing-Up Stick (A Book Review for Washington Lawyers). \u3ci\u3eMiniumum Standards of Judicial Administration\u3c/i\u3e, edited by Arthur T. Vanderbilt (1949)

The book at hand goes a considerable way to fill this need for a set of standards, although the editor, Hon. Arthur T. Vanderbilt, Chief Justice of the Supreme Court of New Jersey, and a former eminent President of the American Bar Association, vigorously emphasizes the fact that these are the minimum standards needed in a practical way to make our court procedure work in the twentieth century. These standards have the firm support of the American Bar Association and the National Conference of Judicial Councils. In the introduction to the volume Judge Vanderbilt tells how and why these standards were developed

Book Review: \u3cem\u3eThe Goldmark Case\u3c/em\u3e by William L. Dwyer

The book is about a libel case tried to a jury in the Superior Court for Okanogan County, Washington. You will not find it in the law reports, for it was not appealed. It ended twenty-one years ago, so it is an old case. Yet in the author\u27s mind it is as fresh as the dawn breeze; and, as the wine people say, it has cellared well. The author is a good man and good lawyer who was lead counsel for the plaintiff. He takes us through the background facts and through the fascinating detail of the many tough decisions that daily went into the preparation and the trial. He tells us of the jury verdict for the plaintiff and of the elation that accompanied it; and then he relates the strange irony that resulted in the verdict\u27s having to be set aside

Criminal Law—Perjury—Depositions—Suggested Legislation

By an amended information, in a recent Washington case, respondent was charged with the crime of perjury in the first degree, the information alleging that respondent came before a notary public for the purpose of giving his deposition which was to be used in a pending civil case, that he was sworn according to law to tell the truth, and that he thereupon testified falsely with the intent that his testimony as written in the deposition be used in that civil case. It affirmatively appeared, both from the allegations of the original information and from the state\u27s admission in open court, that the deposition was never subscribed by respondent. The superior court sustained respondent\u27s demurrer and dismissed the prosecution. Upon the state\u27s appeal, it was held that the demurrer had been properly sustained

The Doctrine of Constructive Fraud in the Washington Law of Taxation

Two recent Washington decisions, Bellingham Development Co. v. Whatcom County and Grays Harbor Pac. R. Co. v. Grays Harbor County present separate phases of a problem which has been frequently considered by the Supreme Court of Washington and concerning which that court has formulated a general rule: namely, that the court will relieve a taxpayer from the burden of an excessive tax where the conduct of the taxing officers has been so improper that it can be called constructively fraudulent , even though the officers acted in good faith. The rule is clearly a proper one, but, like so many general rules , the application of it to a concrete case presents many difficulties, and it is hoped that here some light may be thrown on the characteristics of that will o\u27 the wisp, constructive fraud, so that its presence, or absence, in future cases can be more nearly ascertained. At the outset it must be noted that it is beyond the scope of this comment to attempt a discussion of the remedies available to a taxpayer who has been the victim of improper conduct on the part of the taxing officers, nor does this comment purport to exhaust the field of situations in which the taxpayer has a remedy, because the constructive fraud cases form only a segment of the cases in which the court will grant relief from the effects of improper conduct of the taxing officers

Jurisdiction Over Lands Ownedy by the United States Within the State of Washington: Part I, The Subject in General

Among the unique characteristics of our federal system of government is the concept of the dual sovereignty of the national and state governments over land, things, and persons located within the boundaries of the states. In addition to its position and rights as ultimate sovereign over all territory within its borders, the United States is also a corporate body politic and as such can make contracts, and can hold property, both real and personal. Under this power to own property in its own right the United States has become a great landed proprietor, owning many tracts of land within the exterior boundaries of the states, and it is this fact which gives rise to the problems of jurisdiction and control with which this paper is concerned

Book Review: \u3cem\u3eThe Goldmark Case\u3c/em\u3e by William L. Dwyer

The book is about a libel case tried to a jury in the Superior Court for Okanogan County, Washington. You will not find it in the law reports, for it was not appealed. It ended twenty-one years ago, so it is an old case. Yet in the author\u27s mind it is as fresh as the dawn breeze; and, as the wine people say, it has cellared well. The author is a good man and good lawyer who was lead counsel for the plaintiff. He takes us through the background facts and through the fascinating detail of the many tough decisions that daily went into the preparation and the trial. He tells us of the jury verdict for the plaintiff and of the elation that accompanied it; and then he relates the strange irony that resulted in the verdict\u27s having to be set aside