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Title: Distribution of the GT strength starting from the ground state of 14N

Abstract

Two charge-exchange reactions were performed at intermediate energies in order to investigate the Gamow-Teller strength distribution starting from 14Ng.s. in {beta}+ and {beta}- directions: 14N(d,2He)14C and 14N(3He,t)14O. We describe here a few delicate details of the experimental techniques used in these investigations.

Authors:
; ; ;  [1]; ; ; ;  [2]; ; ; ; ; ;  [3]; ; ; ; ;  [4];  [5]
  1. Vakgroep Subatomaire en Stralingsfysica, Universiteit Gent, B-9000 Gent (Belgium)
  2. Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan)
  3. Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet Muenster, D-48149 Muenster (Germany)
  4. Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, NL-9747 AA Groningen (Netherlands)
  5. Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Cologne (Germany) (and others)
Publication Date:
OSTI Identifier:
20798347
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 819; Journal Issue: 1; Conference: 12. international symposium on capture gamma-ray spectroscopy and related topics, Notre Dame, IN (United States), 4-9 Sep 2005; Other Information: DOI: 10.1063/1.2187912; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BETA DECAY; CARBON 14; CHARGE-EXCHANGE REACTIONS; DEUTERON REACTIONS; DISTRIBUTION; GAMOW-TELLER RULES; GROUND STATES; HELIUM 2; HELIUM 3; HELIUM 3 REACTIONS; NITROGEN 14; NITROGEN 14 TARGET; OXYGEN 14; OXYGEN 14 TARGET

Citation Formats

Negret, A., De Frenne, D., Jacobs, E., Popescu, L., Adachi, T., Fujita, Y., Ogama, T., Shimbara, Y., Baeumer, C., Frekers, D., Grewe, E. W., Haefner, P., Korff, A., Rakers, S., Berg, A. M. van den, Berg, G. P. A., Hunyadi, M., Huu, M. A. de, Woertche, H. J., and Brentano, P. von. Distribution of the GT strength starting from the ground state of 14N. United States: N. p., 2006. Web. doi:10.1063/1.2187912.
Negret, A., De Frenne, D., Jacobs, E., Popescu, L., Adachi, T., Fujita, Y., Ogama, T., Shimbara, Y., Baeumer, C., Frekers, D., Grewe, E. W., Haefner, P., Korff, A., Rakers, S., Berg, A. M. van den, Berg, G. P. A., Hunyadi, M., Huu, M. A. de, Woertche, H. J., & Brentano, P. von. Distribution of the GT strength starting from the ground state of 14N. United States. doi:10.1063/1.2187912.
Negret, A., De Frenne, D., Jacobs, E., Popescu, L., Adachi, T., Fujita, Y., Ogama, T., Shimbara, Y., Baeumer, C., Frekers, D., Grewe, E. W., Haefner, P., Korff, A., Rakers, S., Berg, A. M. van den, Berg, G. P. A., Hunyadi, M., Huu, M. A. de, Woertche, H. J., and Brentano, P. von. Mon . "Distribution of the GT strength starting from the ground state of 14N". United States. doi:10.1063/1.2187912.
@article{osti_20798347,
title = {Distribution of the GT strength starting from the ground state of 14N},
author = {Negret, A. and De Frenne, D. and Jacobs, E. and Popescu, L. and Adachi, T. and Fujita, Y. and Ogama, T. and Shimbara, Y. and Baeumer, C. and Frekers, D. and Grewe, E. W. and Haefner, P. and Korff, A. and Rakers, S. and Berg, A. M. van den and Berg, G. P. A. and Hunyadi, M. and Huu, M. A. de and Woertche, H. J. and Brentano, P. von},
abstractNote = {Two charge-exchange reactions were performed at intermediate energies in order to investigate the Gamow-Teller strength distribution starting from 14Ng.s. in {beta}+ and {beta}- directions: 14N(d,2He)14C and 14N(3He,t)14O. We describe here a few delicate details of the experimental techniques used in these investigations.},
doi = {10.1063/1.2187912},
journal = {AIP Conference Proceedings},
number = 1,
volume = 819,
place = {United States},
year = {Mon Mar 13 00:00:00 EST 2006},
month = {Mon Mar 13 00:00:00 EST 2006}
}
  • The Gamow-Teller (GT) strength distribution in the {beta}- and {beta}+ directions starting from the ground state of 14N has been investigated. A (d,2He) experiment has been performed at KVI, Groningen with Ed=170 MeV and a (3He,t) experiment at RCNP, Osaka with E3He=420 MeV. It is found that, in both cases, the GT mechanism is populating mainly the 2+ excited states in the final nuclei, while the ground state transitions are strongly suppressed. The analysis is ongoing.
  • Purpose: To measure the prompt gamma emission from the important elements found in tissue ({sup 16}O,{sup 12}C and {sup 14}N) in a clinical passive-scatter treatment environment. Methods: The targets (composed of water, Perspex, graphite and liquid nitrogen) were irradiated with a 200 MeV passive-scatter proton beam and the discrete prompt gamma energy spectra was detected by a high resolution 2′ × 2′ LaBr. detector. In order to reduce the high level of radiation produced by the beam line elements, the detector was surrounded by 10 cm of lead to attenuate the scattered gamma-rays entering the detector with an extra 5more » cm thick layer of lead added along the beam direction. A 10 cm thick collimator with a 5 cm × 10 cm rectangular opening was also used. Results: The prompt gamma peaks at 6.13 MeV and 4.44 MeV were clearly identified as a Result of the inelastic nuclear reaction between the protons and the 16O atoms found in the water target. The 6.13 MeV peak was 5% higher than the peak at 4.44 MeV for the water target. The 4.44 MeV peak was the only identified emission in the prompt gamma energy spectra from the graphite target ({sup 12}C). The expected 2.313 MeV peak form the{sup 14}N (liquid nitrogen target) was identified, but the other expected {sup 14}N peaks could not be resolved. Conclusion: Prompt gamma measurements with a passive-scatter proton beam are possible, but the presence of a high amount of background radiation from the patient final collimator presents a challenge at the treatment isocenter. The prominent prompt gamma peaks at 6.13 MeV and 4.44 MeV were identified from the water, Perspex and graphite targets. The prompt gammas from the liquid nitrogen target were difficult to see, but may not be significant in the in-vivo verification process.« less
  • The angular distribution of the neutrons from the tate reactions was (laboratory) energies of approximately 6.5, 6.9, 7.5, 8.1, urements were made for C/sup 13/ at 5.0, 10.2, 10.9, and 13.3 Mev, and for N/sup 15/ at 5.5, 7.7, 7.8, and 13.6 Mev. A calibrated plastic or stilbene scintillator was used in order to obtain absolute differential cross sections. Time-offlight techniques on the Livermore variable energy cyclotron allowed positive identification of the ground- state neutrons. The targets STAC0/sub 2/(58% C/sup 13/) and N/sub 2/(9O% N/sup 15/)! wer e sufficiently thick to average out the effects of possible compound- nucleus contributions.more » From preliminary fits to the C/sup 13/ angular distributions, Glendenning and Bloom have inferred an effective neutron-proton interaction inside the nucleus. (auth)« less
  • Elastic electron scattering has been used to determine the transverse form factor of the /sup 17/O ground state in the effective momentum-transfer range 0.55 < or = q/sub epsilon/ < or = 2.8 fm/sup -1/. The data show considerable deviation from single-particle predictions; in particular, a sizable suppression of the M3 and an enhancement of the high-q side of the M5. Recent shell-model, core-polarization, and meson-exchange calculations are not adequate to explain these effects.
  • We have used the (d,{sup 2}He) reaction to obtain the GT{sup +} strength distribution for {sup 116}Sn {yields}{sup 116}In transitions. Here, {sup 116}In is the intermediate nucleus in the second-order perturbative description of {sup 116}Cd double beta ({beta}{beta}) decay. In this paper we will review what is known about the nuclear matrix elements for the {sup 116}Cd 2{nu}{beta}{beta} decay, discuss the single-state dominance hypothesis and combine our new data with other existing data from charge-exchange reactions to obtain a 2{nu}{beta}{beta}-decay half-life. The deduced value T{sub 1/2}=(4{+-}1)x10{sup 19}y compares well with the one known from direct counting experiments.