124543914
The Production and Distribution of Natural Radiocarbon
120389094
Large Liquid Scintillation Detectors
32865960
Recent advances in low level counting techniques.
Problems involving low level counting techniques are encountered in many diverse fields including biological and chemical tracer studies, archaeo­ logical and geological dating (I), investigations of natural and induced radio­ activities, and the study of fundamental particles. Such a host of methods and variations on methods have been reported that an exhaustive catalog would constitute little more than an annotated bibliography. We have, there­ fore, limited our attention to a few selected examples which seem to be of special interest because of their versatility or their extreme sensitivity. We prefer to organize our discussion around specific problems rather than around types of detectors since this permits a comparison of alternative methods and provides practical examples of various techniques in actual operation. Alpha counting is arbitrarily excluded. For a discussion of photographic methods (radioautographs) the reader is referred to Norris & Woodruff (2) and refer­ ences cited therein. We will discuss the methods developed for the measure­ ment of natural radiocarbon and tritium, cosmic ray produced Be7, and the K(O content of the human body. DOUble-beta decay experiments are consid­ ered since they seem to constitute one of the most difficult of the outstanding problems and because of their importance from the viewpoint of theoretical nuclear physics. Finally, an account is given of recent attempts to detect the neutrino, probably the most difficult low level counting problem of all and one which seems finally on the verge of successful solution. Principles.-The fundamental principles of low level counting are simple: maximize the number of detected events of the desired kind (signal) and minimize all others (background). The number of detected events is, of course, the product of sample size, over-all counting efficiency, and counting time. However, the striking importance of the net sample counting rate is not always fully appreciated. It can be shown (3) from elementary counting statistics, that if the sample rate is small compared with background (which is usually the case in a truly low level problem) and if counting statistics is the limiting source of error (also usually true), then the proper parameter for the comparison of counting methods is S2/B, the ratio of the square of the net sample rate to the background rate. (Any sample strength can be used in making the comparison so long as the same strength is used in testing all methods.) The method giving the maximum value of S2/B will yield the
122516925
Isobar production and elastic scattering in p p interactions from 6-GeV/c to 30-GeV/c
33357835
Comparison of PMTs from three different manufacturers for the CMS-HF forward calorimeter
The builders of the CMS forward hadron calorimeter established a set of specifications for readout PMTs that reflected the physics goals and mechanical needs of the CMS experiment. Three manufacturers, Hamamatsu, Photonis (Philips), and Electron Tubes (EMI), provided candidate PMTs based on these initial requirements. Timing, gain, dark current properties, and single photoelectron spectra of these candidate PMTs were measured. Results show that Hamamatsu PMTs (R7525HA) conform best to the specifications of the Hadron-Forward (HF) Calorimeter.
107708390
COMPUTER MONITORING AND CONTROL SYSTEM FOR THE NAL 200-MeV LINAC.
115233092
Asymmetry in Angular Distribution of Neutrons from Muon Capture in Spin 0 Nuclei.
18688326
Reformulation and interpretation of the SMS braneworld
We reformulate the Shiromizu, Maeda and Sasaki (SMS) braneworlds within the framework of the five-dimensional Einstein equations. In many applications of the braneworld Einstein field equations, the Weyl term is attributed to the bulk, thus splitting the non-Einsteinian terms into 'bulk' and 'brane' terms. Here by employing standard geometrical identities, we show that such a split is non-unique, since they get mixed up in different formulations. An important consequence of this non-uniqueness is that even though the full brane-bulk systems in all such formulations are completely equivalent, important differences can arise were one to truncate different formulations by throwing away the associated 'bulk' terms. This is particularly likely to be the case in more general anisotropic/inhomogeneous settings with non-AdS bulks, in which the common truncation of the SMS (which throws away the Weyl term) would not coincide with the full system. We emphasize that rather than providing support for any particular truncation, these differences show clearly the dangers of using any truncated equations and provide a strong argument in favour of studying the full brane–bulk system. The different formulations we provide also permit different ways of approaching the full brane–bulk system which may greatly facilitate its study. An example of this is the second-order nature of the formulations given here as opposed to SMS's formulation which is third order.