Liquid Xenon Detectors for Positron Emission Tomography

PET is a functional imaging technique based on detection of annihilation photons following beta decay producing positrons. In this paper, we present the concept of a new PET system for preclinical applications consisting of a ring of twelve time projection chambers filled with liquid xenon viewed by avalanche photodiodes. Simultaneous measurement of ionization charge and scintillation light leads to a significant improvement to spatial resolution, image quality, and sensitivity. Simulated performance shows that an energy resolution of <10% (FWHM) and a sensitivity of 15% are achievable. First tests with a prototype TPC indicate position resolution <1 mm (FWHM).Comment: Paper presented at the International Nuclear Physics Conference, Vancouver, Canada, 201

A review of the predictability and prediction of ENSO

A hierarchy of El Niño-Southern Oscillation (ENSO) prediction schemes has been developed during the Tropical Ocean-Global Atmosphere (TOGA) program which includes statistical schemes and physical models. The statistical models are, in general, based on linear statistical techniques and can be classified into models which use atmospheric (sea level pressure or surface wind) or oceanic (sea surface temperature or a measure of upper ocean heat content) quantities or a combination of oceanic and atmospheric quantities as predictors. The physical models consist of coupled ocean-atmosphere models of varying degrees of complexity, ranging from simplified coupled models of the “shallow water” type to coupled general circulation models. All models, statistical and physical, perform considerably better than the persistence forecast in predicting typical indices of ENSO on lead times of 6 to 12 months. The TOGA program can be regarded as a success from this perspective. However, despite the demonstrated predictability, little is known about ENSO predictability limits and the predictability of phenomena outside the tropical Pacific. Furthermore, the predictability of anomalous features known to be associated with ENSO (e.g., Indian monsoon and Sahel rainfall, southern African drought, and off-equatorial sea surface temperature) needs to be addressed in more detail. As well, the relative importance of different physical mechanisms (in the ocean or atmosphere) has yet to be established. A seasonal dependence in predictability is seen in many models, but the processes responsible for it are not fully understood, and its meaning is still a matter of scientific discussion. Likewise, a marked decadal variation in skill is observed, and the reasons for this are still under investigation. Finally, the different prediction models yield similar skills, although they are initialized quite differently. The reasons for these differences are also unclear

TauFinder: A Reconstruction Algorithm for τ Leptons at Linear Colliders

An algorithm to find and reconstruct τ leptons was developed, which targets τs that produce high energetic, low multiplicity jets as can be observed at multi TeV e+e− collisions. However, it makes no assumption about the decay of the τ candidate thus finding hadronic as well as leptonic decays. The algorithm delivers a reconstructed τ as seen by the detector. This note provides an overview of the algorithm, the cuts used and gives some evaluation of the performance. A first implementation is available within the ILC software framework as a MAR- LIN processor . Appendix A is intended as a short user manual

Measurement of stau_1 pair production at CLIC

We present a study performed for the CLIC Conceptual Design Report Volume 3 on the measurement of stau_1 pair production at sqrt(s) = 1.4 TeV. Only the hadronic decay of taus are considered. Results obtained using full detector simulation and including beam-induced backgrounds for the mass and for the production cross section of the stau_1 are discussed

The CLIC ILD CDR Geometry for the CDR Monte Carlo Mass Production

The CLIC ILD CDR detector for the Monte Carlo event simulation is described in a GEANT4 application, with some parameters available in a database and XML files. This makes it difficult to quickly “look up” interesting parameters of the detector geometry used for the simulation. This note summarises the important geometrical parameters and some details of the implemented detector components

The CLIC SiD CDR Detector Model for the CLIC CDR Monte Carlo Mass Production

The CLIC SiD CDR detector model for full simulation using GEANT4 is presented in this note. It is used for the Monte Carlo mass production for the CLIC CDR. The CLIC SiD CDR detector model is based on the SiD detector concept developed for the ILC. This note is intended as a reference document for the geometry description, which is written in xml. All relevant numbers are presented in a comprehensive form and several illustrations are added to display the features of the detector model

Particle Flow Performance at CLIC

Particle Flow has been used very successfully in the studies for linear colliders. At CLIC with an energy of 3 TeV considerable machine background is present in the detector. Using timing cuts based on particle flow objects this background can be reduced significantly. A systematic study is carried out to understand the dependence of the jet energy resolution on the jet energy and angle. The performance of particle flow is evaluated based on the energy and mass resolution of W and Z particles in full simulation and reconstruction in the presence of background for both detector concepts considered for CLIC