A reaction detector for CBM

Physical Review C, 2000

We report on precision measurements of the cross sections for the reactions p p→⌳ ⌳, p p→⌳ ⌺ 0 , and p p→⌺ 0 ⌳ in the region below 5 MeV excess kinetic energy above reaction threshold. For the p p→⌳ ⌳ measurement, the data represent a third and definitive scan through the threshold region by this experiment. Improvements in the detector system and analysis techniques, coupled with greatly increased statistics, have negated the question of the existence of a near-threshold resonance as had been indicated in our earlier, lower-statistics studies. The high statistics permit the first extraction of the polarization information at these low energies. We also report the first measurement of the cross section for the complementary reactions p p →⌳ ⌺ 0 ϩc.c. at excess energies up to 2.5 MeV. This allows a comparison of the onset of ⌳ ⌳ production to that of ⌳ ⌺ 0 and ⌺ 0 ⌳. The data show no evidence for near-threshold resonance structures in either reaction channel. Further, the p p→⌳ ⌺ 0 ϩc.c. reactions exhibit a larger P-wave fraction close to threshold compared to p p→⌳ ⌳.

Nuclear Instruments and Methods, 1965

A sol id state system is described which applies the logarithmic method of computing the product E x dE/dx to the problem of mass discrimination of charged particles in counter telescopes. The basic conversion circuit uses the emitter-base junction of a transistor as the logarithmic element. Also described are the delay-line clipped amplifiers, zero-crossover coincidence circuits, and single channel pulse height analyzers used with the logarithmic converters.

Nuclear Physics A, 2001

A stack of annular detectors made of high-purity germanium was used to measure simultaneously pd → 3 H π + and pd → 3 He π 0 differential cross sections at beam momenta of 750 MeV/c, 800 MeV/c, and 850 MeV/c over a large angular range. The extracted total cross sections for the pd → 3 He π 0 reactions bridge a gap between near threshold data and those in the resonance region. The ratio of the cross sections for the two reaction channels taken at the same η = p cm π /m π yields 2.11 ± 0.08 indicating that a deviation from isospin symmetry is very small. 

gu.edu.pk

Experimental reaction parameters for the reaction of 208Pb projectiles with 197Au targets have been reported in this paper. Thin layers of 197Au were vacuum deposited on three sheets of mica and three sheets of CN-85 and exposed to a normal bunched beam of ...

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007

ABSTRACT We describe a device to study reactions relevant for the Single Event Effect (SEE) in microelectronics by means of 200 A and 300 A MeV, inverse kinematics, Si+H and Si+D reactions. The work is focused on the possibility to measure Z=2–14 projectile fragments as efficiently as possible. During commissioning and first experiments the fourth quadrant of the CELSIUS storage ring acted as a spectrometer to register fragments in two planes of Si strip detectors in the angular region 0∘–0.6∘. A combination of ring-structured and sector-structured Si strip detector planes operated at angles 0.6∘–1.1∘. For specific event tagging a Si+ phoswich scintillator wall operated in the range 3.9∘–11.7∘ and Si ΔE–E telescopes of CHICSi type operated at large angles.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1994

A ~ctmrne~~ has been constructed far meas~ments of low by~oge~ con~nt~tio~s by detecting 4.43 MeV y-rays from the reaction '~ti5N,~y)l~C at the 6.39 MeV resonance. It consists of an annular large-volume (2600 cm3) BW detector, an annular plastic-detector anticoincidence shield around it, and Pb and Cd shields. The spectrometer is placed in the target hall of the laboratory located 20 m deep inside the granite bedrock. The background counting rate arising mainly from impurity of the BG0 materials is 0.023 Rz in the energy range 3.9-4.9 MeV. The detection sensitivity of 10 at.ppm H in silicon substrates was determined by measurements of filtration distributions of 2 x 1O13-1 x 1Ol7 40 keV protons crnm2 in singlecrystal silicon substrates. The rage profiles of 40 keV protons simulated by molecular dynamics calculations rest&d in the correction factor of 1.21 for the commonly used electronic stopping pawer of silicon given by Ziegler et al. [The &opping Power and Ranges of Ions in Matter (Pergnmon, New York, 1985) vol. 11.

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 2007

A fast screening technique to evaluate detector response was demonstrated using a silicon detector. Pulse height was measured for H, He, Be, C, O, Mg, Si, Ni, Zr and Au ions over a wide energy range using a time-of-flight (TOF) telescope. Using a scattering or recoil process, a secondary beam with a continuous energy distribution but low intensity is generated to avoid direct beam exposure of the Si detector. Prior to impinging on the Si detector, the energy of individual ions is determined from the TOF and its tabulated isotopic mass. The pulse height-energy calibration for ions with a given atomic number can be described by a linear relationship with small systematic deviations. For particles that have the same velocity ($500 keV/nucleon), a non-linear dependence on efficiency of electron-hole pair collection is observed as a function of electronic stopping power. The detector response is studied using He ions, and the measured energy resolution is given as function of deposition energies over a wide energy range. r

The integral measurement of the C-12(n,p)B-12 reaction was performed at the neutron time-of-flight facility n_TOF at CERN. The total number of B-12 nuclei produced per neutron pulse of the n_TOF beam was determined using the activation technique in combination with a time-of-flight technique. The cross section is integrated over the n_TOF neutron energy spectrum from reaction threshold at 13.6 MeV to 10 GeV. A good reproduction of the integral cross section derived from measurements is obtained with TALYS-1.6 calculations, with optimized parameters.

Referred to by some philosophers as "the knot of the universe," investigations concerning human selfhood and subjectivity can help unravel questions of central contemporary relevance, such as what it is to be human in a globalized, secular world. This talk aims to unravel the concept of the self in Islamic thought through a global philosophy approach. Beginning with the Qur'an and then following the various streams of Islamic thought such as theology (kalām), philosophy (falsafa), and Sufism, this talk shows how Muslim thinkers reveal themselves to be fundamentally concerned with the problem of the human condition. Their manner of addressing this central issue from their differing perspectives devolves on the cultivation of what can be called both an anthropocentric and anthropocosmic understanding of the self that emphasizes selfknowledge, self-cultivation, and self-transformation on the one hand and a relational view of the self and the cosmos on the other.