An overlapping multichannel detector system

doi:10.1016/0029-554X(75)90276-1

Nuclear Instruments and Methods

Volume 125, Issue 2, 1 April 1975, Pages 257-264

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Abstract

A multichannel system for the detection of medium-energy electrons is described. The system consists of 24 overlapping plastic scintillators which define 45 momentum channels. Fast-logic circuitry is used to process the signals and the data is read into an on-line computer via a buffer memory. The performance is characterized by a high count-rate handling ability, good background rejection and moderate resolution.

References (3)

P.K.A. De Witt Huberts et al.
Nucl. Instr. and Meth.
(1969)

There are more references available in the full text version of this article.

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Longitudinal electroexcitation of the low-lying states in 42Ca and 44Ca
1989, Nuclear Physics, Section A
The form factors in electron scattering have been measured for 2⁺, 3⁻ and 5⁻ states up to 7 MeV excitation in ⁴²Ca and ⁴⁴Ca. The range of the incident electron energy and scattering angles were 62.5–250 MeV at relatively forward angles, over the momentum transfer from 0.4–1.8 fm⁻. The reduced transition probabilities B(El) for these states were determined using Tassie-type and shell-model-type transition densities. It is shown that the characteristics and the differences of the observed 2⁺₁ and 2⁺₂ form factors in ⁴²Ca and ⁴⁴Ca are explained by deformation effect and the coexistence model was well verified in ⁴²Ca. The form factor of the 6.1 MeV transition in ⁴²Ca may be interpreted as an isoscalar dipole transition by its E3-like q-dependence similar to those in the self-conjugate nucleus ⁴⁰Ca, and the isoscalar E1 transition density is deduced.
Elastic electron scattering from the isotopes 35Cl and 37Cl
1980, Nuclear Physics A
The charge structure of ³⁵Cl and ³⁷Cl has been investigated using the technique of elastic electron scattering. Data were collected at the University of Saskatchewan Linear Accelerator Laboratory with incident electron energies of 116 and 194 MeV and at scattering angles ranging from 45 to 140°. The data span a range of q between 0.60 and 1.71 fm⁻¹. Phase-shift fits to a threeparameter Fermi distribution yield model-dependent rms charge-radius values of 3.388 ±0.015 fm for ³⁵Cl and 3.384±0.015 fm for ³⁷Cl.
High resolution electron scattering facility at the Darmstadt linear accelerator (DALINAC). III. Detector system and performance of the electron scattering apparatus
1978, Nuclear Instruments and Methods
The multichannel detector system of the energy-loss electron scattering facility at the Darmstadt linear accelerator is described. The system consists of 36 overlapping plastic scintillators backed up by a large Čerenkov counter. Fast logic circuitry (300 MHz) is used to form a pattern of coincidence and anticoincidence bins defining 69 momentum channels. Each channel has a momentum acceptance of Δp/p = 3 × 10⁻⁴. The over all energy resolution in the electron scattering spectra is ΔE ≈ 30 keV (fwhm) taken with the targets of typical thickness of about px = 20 mg/cm² and is largely independent of bombarding energy. Examples of electron scattering spectra from ¹⁴N, ¹⁶O, ⁴⁰Ca and ²⁰⁸Pb are presented. The complete system has worked successfully first in the summer of 1974 and has since been in operation continously without major breakdown.
Electron scattering from 17O
1978, Nuclear Physics, Section A
Cross sections for elastic and inelastic scattering of electrons from ¹⁷O have been measured for momentum transfers up to 1.2 fm⁻¹. The elastic cross section indicates that the rms charge radii of ¹⁷O and ¹⁶O are equal to within a few parts in a thousand: $〈r^{2}_{17} 〉^{12} 〈r^{2}_{16} 〉^{12} = 1.0015 ± 0.0025$ . Reduced transition probabilities and ground-state radiative widths are deduced for ¹⁷O excited states below 9 MeV. Various aspects of the inelastic spectrum are discussed, with emphasis on the “single-panicle” levels at 0.871 ( $12^{+}$ ) and 5.083 ( $32^{+}$ ) MeV, the levels at 7.569 ( $72^{−}$ ) and 7.378 ( $52^{+}$ ) MeV, and the spectrum of electric octupole excitations.
Electroexcitation of the giant resonance of 17O
1977, Nuclear Physics, Section A
The giant resonance region of ¹⁷O has been investigated by means of inelastic electron scattering in a momentum transfer range 0.34–0.98 fm⁻¹. The data reveal a broad dipole resonance centred at 22–23 MeV excitation, with strength extending down to 10–12 MeV. A smaller resonance found between 17.5 and 19.6 MeV excitation has a form factor consistent with a C2 transition. Levels at 16.5 and 17.1 MeV excitation are also reported for the first time. Fine structure is observed between 11 and 15 MeV which correlates well with the positions of previously known levels. A particle-hole model with the Kuo-Brown residual interaction gives a satisfactory description of the strength distribution and q-dependence of the giant dipole resonance, although a scale factor of 1.85 is required to achieve agreement in magnitude.
Electroexcitation of giant resonances in 181Ta
1977, Nuclear Physics, Section A
The giant resonance region of ¹⁸¹Ta has been investigated by means of inelastic electron scattering, with primary electron energies of 79.1 to 118.3 MeV. A peak-fitting procedure was employed to separate the measured spectrum into nine different resonance components. Multipolarity and strength assignments were deduced using DWBA analysis with the Goldhaber-Teller and Steinwedel-Jensen models. In addition to the well-known giant dipole structure, other resonances were identified at 23.2 ± 0.3 MeV (E2), 9.5 ± 0.2 and 11.5 ± 0.2 MeV (E2 or EO), 19.5 ± 0.8 MeV (E3), 3.70 ± 0.14 MeV (E3 or E4), and 5.40 ± 0.15 MeV (E4 or E5). The model dependence of the analysis is discussed.

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^☆: Work supported by the Atomic Energy Control Board of Canada.

^†: Present address: Argonne National Laboratory, Argonne, Illinois 60439, U.S.A.

⁺: Present address: Physics Department, Stellenbosch University, Stellenbosch C.P., South Africa.

^§: Present address: Nuclear Physics Group, Graduate Research Center, University of Massachusetts, Amherst, Massachusetts, U.S.A.

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Nuclear Instruments and Methods

Abstract

References (3)

Nucl. Instr. and Meth.

Cited by (14)

Longitudinal electroexcitation of the low-lying states in <sup>42</sup>Ca and <sup>44</sup>Ca

Elastic electron scattering from the isotopes <sup>35</sup>Cl and <sup>37</sup>Cl

High resolution electron scattering facility at the Darmstadt linear accelerator (DALINAC). III. Detector system and performance of the electron scattering apparatus

Electron scattering from <sup>17</sup>O

Electroexcitation of the giant resonance of <sup>17</sup>O

Electroexcitation of giant resonances in <sup>181</sup>Ta

An overlapping multichannel detector system☆

Abstract

Nucl. Instr. and Meth.