120797993
Comment on precise single-scattering optical-potential fit to 1 GeV p-$sup 4$He elastic scattering
119549050
ELECTRON SCATTERING FROM DEFORMED NUCLEI.
A general phenomenological theory is developed for the calculation of both elastic and inelastic transverse and longitudinal form factors for electron scattering from nuclei whose surfaces are deformed according to the expression $R+{(4\ensuremath{\pi})}^{\frac{1}{2}}{\ensuremath{\Sigma}}_{\mathrm{lm}}{\stackrel{^}{a}}_{\mathrm{lm}}{Y}_{\mathrm{lm}}(\stackrel{^}{\mathcal{r}})$. Here, the ${\stackrel{^}{a}}_{\mathrm{lm}}$ are operators in the nuclear Hilbert space, whose detailed dynamical character is left unspecified. The effects of deformation on the scattering, to any desired accuracy, are contained in reduced matrix elements of tensor products of the ${\stackrel{^}{a}}_{\mathrm{lm}}$. These are then treated as phenomenological parameters whose values are to be fixed from an analysis of the scattering cross sections, particularly at high momentum transfer. All the static and transition multipole moments of the nucleus are thereby determined, at least in principle. The Helm model and its generalization to transverse scattering are obtained in the small-deformation limit. The theory is used to analyze the Coulomb elastic and inelastic (to the 1.3-MeV ${\frac{3}{2}}^{+}$ level) scattering of electrons from $^{59}\mathrm{Co}$, as well as the magnetic elastic and inelastic scattering from $^{10}\mathrm{B}$. It is shown that the contribution of the deformation to elastic monopole scattering may be interpreted as due to an effective, oscillatory, spherically symmetric "modulating-charge" distribution, superimposed upon the more usual smeared uniform distribution. It is therefore suggested that the oscillations in the charge distribution which seem to be required in order to fit the high-energy elastic scattering from $^{40}\mathrm{Ca}$ and other nuclei may be due to deformations.
122327020
Dispersion corrections to elastic electron scattering by 16O and 12C
Abstract Longitudinal dispersion corrections to elastic electron scattering from 16 O and 12 C are calculated using oscillator wave functions and closure approximation. Near the first diffraction minimum, the contributions from the Pauli, COM and self-correlations almost cancel. The correction increases away from the minimum.
115626406
Performance confirmation of the Belle II imaging Time Of Propogation (iTOP) prototype counter
The Bell Detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider performed extremely well, logging an integrated luminosity an order of magnitude higher than the design baseline. With this inverse attobarn of integrated luminosity, time-dependent CP-violation inn the 3rd generation beauty quarks was firmly established, and is now a precision measurement. Going beyond this to explore if the Kobayashi-Maskawa mechanism is the only contributor to quark-mixing, and to interrogate the flavor sector for non-standard model enhancements, requires a detector and accelerator capable of topping this world-record luminosity by more than an order of magnitude. The Belle II detector at the upgraded Super-KEKB accelerator has been designed to meet this highly ambitious goal of operating at a luminosity approaching 10{sup 36} cm{sup -2} s{sup -1}. Such higher event rates and backgrounds require upgrade of essentially all detector subsystems, as well as their readout. Comparing the Belle composite (threshold Aerogel + Time of Flight) particle identification (PID) system with the DIRC employed by BaBar, quartz radiator internal Cherenkov photon detection proved to have higher kaon efficiency and lower pion fake rates. However, because the detector structure and CsI calorimeter will be retained, an improved barrel PID must fit within a very narrowmore » envelope, as indicated in Figure 1. To effectively utilize this space, a more compact detector concept based on the same quartz radiators, but primarily using photon arrival time was proposed. This Time Of Propagation (TOP) counter was studied in a number of earlier prototype tests. Key to the necessary 10's of picosecond single-photon timing has been the development of the so-called SL-10 Micro-Channel Plate Photo-Multiplier Tube (MCP-PMT), which has demonstrated sub-40 ps single photon Transit Time Spread TTS. Further simulation study of this detector concept indicated that a focusing mirror in the forward direction, as well as a modest image expansion volume and more highly pixelated image plane improve the theoretical detector performance, since timing alone is limited by chromatic dispersion of the Cherenkov photons. This imaging-TOP (or iTOP) counter is the basis of Belle II barrel PID upgrade. However, a number of critical performance parameters must be demonstrated prior to releasing this prototype design for production manufacture.« less
120772520
Time projection chambers with integrated pixels and their application to fast neutron detection and dark matter searches
Abstract We present our most recent work on the use of integrated silicon pixel electronics to read out gas-filled Time Projection Chambers (TPCs). Such detectors have great promise to measure the direction and energy of neutral particles via nuclear recoils that ionize the gas. We report on ongoing studies and refinement of the first prototype constructed at the University of Hawaii. We present data on the detection of alpha particles and fast neutrons using Ar:CO 2 (70:30) and He:CO 2 (70:30) gas, respectively. We also present plans and sensitivity estimates for a future Dark Matter search based on the technology under study.
45943105
Tuning into UHE Neutrinos in Antarctica - The ANITA Experiment
ice will produce a radio pulse by the means of the Askaryan effect. The large radio transparency of ice allows for such a pulse to be recorded by a cluster of balloon-borne antennas. The details of the ANITA instrument, now in a construction phase, and the science we hope to achieve is discussed. In order to prepare for the main mission, we have flown ANITA-lite during the 2003/04 austral season. ANITA-lite consisted of two quad-ridge horn antennas and a prototype RF (radio frequency) triggering and recording system. Here we present the results of an impulsive RF background survey of Antarctica, as well as proof-of-principle gain, tracking, and timing calibrations conducted by observing solar radio emissions and calibration radio-pulses. A preliminary UHE neutrino flux limit based on ANITA-lite data is also presented.
110321484
Recent progress in the development of a B-factory monolithic active pixel detector
Abstract Due to the need for precise vertexing at future higher luminosity B-factories with the expectedly increasing track densities and radiation exposures, upgrade of present silicon strip detectors with thin, radiation resistant pixel detectors is highly desired. Considerable progress in the technological development of thin CMOS based Monolithic Active Pixel Sensors (MAPS) in the last years makes them a realistic upgrade option and the feasibility studies of their application in Belle are actively pursued. The most serious concerns are their radiation hardness and their read-out speed. To address them, several prototypes denoted as Continuous Acquisition Pixel (CAP) sensors have been developed and tested. The latest of the CAP sensor prototypes is CAP3, designed in the TSMC 0.25 μ m process with a 5-deep sample pair pipeline in each pixel. A setup with several CAP3 sensors will be used to assess the performance of a full scale pixel read-out system running at realistic read-out speed. The results and plans for the next stages of R&D towards a full Pixel Vertex Detector (PVD) are presented.