arXiv subjects

A. Chatterjee

Publications and source records attributed to A. Chatterjee.

248 records · Page 14Linked to original sources

arXiv2006

Influence of projectile - breakup threshold on complete fusion

Complete fusion excitations for 11,10B+159Tb have been measured at energies around the respective Coulomb barriers, and the existing complete fusion measurements for 7Li+159Tb have been extended to higher energies. The measurements show significant reduction of complete fusion cross sections at above-barrier energies for both the reactions, 10B+159Tb and 7Li+159Tb, when compared to those for 11B+159Tb. The comparison shows that the extent of suppression of complete fusion cross sections is correlated with the -separation energies of the projectiles. Also, the two reactions, 10B+159Tb and 7Li+159Tb were found to produce incomplete fusion products at energies near the respective Coulomb barriers, with the - particle emitting channel being the favoured incomplete fusion process in both the cases.

nucl-ex↗

arXiv2006

A Sub-Gaussian Berry-Esseen Theorem for the Hypergeometric Distribution

In this paper, we derive a necessary and sufficient condition on the parameters of the Hypergeometric distribution for weak convergence to a Normal limit. We establish a Berry-Esseen theorem for the Hypergeometric distribution solely under this necessary and sufficient condition. We further derive a nonuniform Berry-Esseen bound where the tails of the difference between the Hypergeometric and the Normal distribution functions are shown to decay at a sub-Gaussian rate.

math.PR↗

arXiv2005

Evidence for transfer followed by breakup in 7Li + 65Cu

The observation of a large cross-section for the alpha + d channel compared to breakup into the alpha + t channel from an exclusive measurement for the 7Li+65Cu system at 25 MeV is presented. A detailed analysis of the angular distribution using coupled channels Born approximation calculations has provided clear evidence that the observed alpha + d events arise from a two step process, i.e. direct transfer to the 2.186 MeV (3+) resonance in the alpha + d continuum of 6Li followed by breakup, and are not due to final state interaction effects.

nucl-ex↗

arXiv2005

Measurement of the Vector and Tensor Polarisation of Proton and Deuteron Beams

Measurement of the d + d -> 4He + eta reaction using vector and tensor polarised beam has been performed at COSY using Big Karl magnetic spectrograph. The beam polarisation necessary for obtaining the vector and tensor analysing power for this reaction was measured. The method and the results of the tensor polarisation measurement of the deuteron beam are presented.

hep-ex↗

arXiv2005

A precision determination of the mass of the $η$ meson

Several processes of meson production in proton-deuteron collisions have been measured simultaneously using a calibrated magnetic spectrograph. Among these processes, the $η$ meson is seen clearly as a sharp missing--mass peak on a slowly varying background in the $p+d\to ^3\textrm{He} +X$ reaction. Knowing the kinematics of the other reactions with well determined masses, it is possible to deduce a precise mass for the $η$ meson. The final result, $m(η)=547.311\pm 0.028 \textrm{(stat)} \pm 0.032 \textrm{(syst) MeV/c}^2$, is significantly lower than that found by the recent NA48 measurement, though it is consistent with values obtained in earlier counter experiments.

hep-ex↗

arXiv2005

Monitoring of Sudden Ionospheric Disturbances (SID) from Kolkata (INDIA)

We report our first results of monitoring sudden ionospheric disturbances (SID). We present data taken continuously for two weeks during 20th Sept. 2002 and 4th Oct. 2002. We compare the effects of solar flares of the VLF signal with those obtained by GOES Satellite of NASA monitoring in X-rays and found excellent agreement.

astro-ph↗

arXiv2002

Coordinated, Interactive Data Visualization for Neutron Scattering Data

The overall design of the Integrated Spectral Analysis Workbench (ISAW), being developed at Argonne, provides for an extensible, highly interactive, collaborating set of viewers for neutron scattering data. Large arbitrary collections of spectra from multiple detectors can be viewed as an image, a scrolled list of individual graphs, or using a 3D representation of the instrument showing the detector positions. Data from an area detector can be displayed using a contour or intensity map as well as an interactive table. Selected spectra can be displayed in tables or on a conventional graph. A unique characteristic of these viewers is their interactivity and coordination. The position "pointed at" by the user in one viewer is sent to other viewers of the same DataSet so they can track the position and display relevant information. Specialized viewers for single crystal neutron diffractometers are being developed. A "proof-of-concept" viewer that directly displays the 3D reciprocal lattice from a complete series of runs on a single crystal diffractometer has been implemented.

physics.data-an↗

arXiv2002

Analyzing Single Crystal Time-of-Flight Neutron Data

Software for time-of-flight single crystal diffractometer (SCD) data visualization and analysis was originally written to be run in batch mode on VMS-VAX systems. Modern computers and software tools allow a new level of visualization and user interaction. The Integrated Spectral Analysis Workbench (ISAW) is being extended and customized for SCD measurements. To this end, new viewers and operators have been added to ISAW. One of the new operators allows running a program written in another language, such as C or FORTRAN, to integrate tested software into the object-oriented package. This provides a method for preserving earlier software development while making use of modern tools.

cond-mat.mtrl-sci↗

arXiv2002

User software for the next generation

New generations of neutron scattering sources and instrumentation are providing challenges in data handling for user software. Time-of-Flight instruments used at pulsed sources typically produce hundreds or thousands of channels of data for each detector segment. New instruments are being designed with thousands to hundreds of thousands of detector segments. High intensity neutron sources make possible parametric studies and texture studies which further increase data handling requirements. The Integrated Spectral Analysis Workbench (ISAW) software developed at Argonne handles large numbers of spectra simultaneously while providing operations to reduce, sort, combine and export the data. It includes viewers to inspect the data in detail in real time. ISAW uses existing software components and packages where feasible and takes advantage of the excellent support for user interface design and network communication in Java. The included scripting language simplifies repetitive operations for analyzing many files related to a given experiment. Recent additions to ISAW include a contour view, a time-slice table view, routines for finding and fitting peaks in data, and support for data from other facilities using the NeXus format. In this paper, I give an overview of features and planned improvements of ISAW. Details of some of the improvements are covered in other presentations at this conference.

cs.GR↗

arXiv2002

Developments for the IPNS Data Acquisition System Upgrade

The Intense Pulsed Neutron Source has been an operating user facility for more than 20 years. Development of an upgrade for the data acquisition system has been in progress for some time now. Now that the initial installation on the test bed instrument (HRMECS) is completed new features and possibilities are starting to come forward. Run setup is moving from large monolithic programs to more flexible scripting. EPICS based controls allow flexible and extendable instrument configurations. Hardware is also being made more flexible. This flexibility allows implementation of new methods of binning data, that better match instrument resolution. This allows better use of memory and disk space. Increased flexibiliy has also allowed use of the new time-of-flight modules in applications past their original intent.

physics.ins-det↗

arXiv2002

Light charged particle evaporation from hot ${31}^$P nucleus at E$^*$ ~ 60 MeV

The energy spectra of evaporated light charged particles (LCP) $α$, p, d and t have been measured in $7^$Li(47 MeV) + ${24}^$Mg and ${19}^$F(96 MeV)+ ${12}^$C reactions. Both the systems populate the same compound nucleus ${31}^$F at excitation energy E$^*$ ~ 60 MeV. It has been observed that the light particle spectra obtained in Li + Mg reaction follow standard statistical model prediction, whereas a deformed configuration of the compound nucleus is needed to explain the LCP spectra for F + C reaction, which has been attributed to the effect of larger input angular momentum in the case of ${19}^$F(96 MeV)+ ${12}^$C system.

nucl-ex↗

arXiv2001

Exclusive light particle measurements for the system $^{19}$F + $^{12}$C at 96 MeV

Decay sequence of hot ${31}^$P nucleus has been investigated through exclusive light charged particle measurements in coincidence with individual evaporation residues using the reaction ${19}^$F (96 MeV) + ${12}^$C. Information on the sequential decay chain have been extracted by confronting the data with the predictions of the statistical model. It is observed from the present analysis that such exclusive light charged particle data may be used as a powerful tool to probe the decay sequence of the hot light compound systems.

nucl-ex↗

arXiv1999

Measurement of p + d -> 3He + eta in S(11) Resonance

We have measured the reaction p + d -> 3He + eta at a proton beam energy of 980 MeV, which is 88.5 MeV above threshold using the new ``germanium wall'' detector system. A missing--mass resolution of the detector system of 2.6% was achieved. The angular distribution of the meson is forward peaked. We found a total cross section of (573 +- 83(stat.) +- 69(syst.))nb. The excitation function for the present reaction is described by a Breit Wigner form with parameters from photoproduction.

nucl-ex↗

arXiv1998

Evaporation of alpha particles from $^31$P nucleus

The energy spectra of alpha particles have been measured in coincidence with the evaporation residues for the decay of the compound nucleus $^31$P produced in the reaction $^19$F (96 MeV) + $^12$C. The data have been compared with the predictions of the statistical model code CASCADE. It has been observed that significant deformation effect in the compound nucleus need to be considered in order to explain the shape of the evaporated alpha particle energy spectra.

nucl-ex↗