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1. Border of the island of inversion: Unbound states in Ne 29

Author

Holl, M, Holl, M, Lindberg, S, Heinz, A, Kondo, Y, Nakamura, T, Tostevin, JA, Wang, H, Nilsson, T, Achouri, NL, Al Falou, H, Atar, L, Aumann, T, Baba, H, Boretzky, K, Caesar, C, Calvet, D, Chae, H, Chiga, N, Corsi, A, Crawford, HL, Delaunay, F, Delbart, A, Deshayes, Q, Díaz Fernández, P, Dombrádi, Z, Douma, CA, Elekes, Z, Fallon, P, Gašparić, I, Gheller, JM, Gibelin, J, Gillibert, A, Harakeh, MN, Hirayama, A, Hoffman, CR, Horvat, A, Horváth, Hwang, JW, Isobe, T, Kahlbow, J, Kalantar-Nayestanaki, N, Kawase, S, Kim, S, Kisamori, K, Kobayashi, T, Körper, D, Koyama, S, Kuti, I, Lapoux, V, Marqués, FM, Masuoka, S, Mayer, J, Miki, K, Murakami, T, Najafi, M, Nakano, K, Nakatsuka, N, Obertelli, A, De Oliveira Santos, F, Orr, NA, Otsu, H, Ozaki, T, Panin, V, Paschalis, S, Revel, A, Rossi, D, Saito, AT, Saito, TY, Sasano, M, Sato, H, Satou, Y, Scheit, H, Schindler, F, Schrock, P, Shikata, M, Shimizu, Y, Simon, H, Sohler, D, Sorlin, O, Stuhl, L, Takeuchi, S, Tanaka, M, Thoennessen, M, Törnqvist, H, Togano, Y, Tomai, T, Tscheuschner, J, Tsubota, J, Uesaka, T, Yang, Z, Yasuda, M, Yoneda, K, Holl, M, Holl, M, Lindberg, S, Heinz, A, Kondo, Y, Nakamura, T, Tostevin, JA, Wang, H, Nilsson, T, Achouri, NL, Al Falou, H, Atar, L, Aumann, T, Baba, H, Boretzky, K, Caesar, C, Calvet, D, Chae, H, Chiga, N, Corsi, A, Crawford, HL, Delaunay, F, Delbart, A, Deshayes, Q, Díaz Fernández, P, Dombrádi, Z, Douma, CA, Elekes, Z, Fallon, P, Gašparić, I, Gheller, JM, Gibelin, J, Gillibert, A, Harakeh, MN, Hirayama, A, Hoffman, CR, Horvat, A, Horváth, Hwang, JW, Isobe, T, Kahlbow, J, Kalantar-Nayestanaki, N, Kawase, S, Kim, S, Kisamori, K, Kobayashi, T, Körper, D, Koyama, S, Kuti, I, Lapoux, V, Marqués, FM, Masuoka, S, Mayer, J, Miki, K, Murakami, T, Najafi, M, Nakano, K, Nakatsuka, N, Obertelli, A, De Oliveira Santos, F, Orr, NA, Otsu, H, Ozaki, T, Panin, V, Paschalis, S, Revel, A, Rossi, D, Saito, AT, Saito, TY, Sasano, M, Sato, H, Satou, Y, Scheit, H, Schindler, F, Schrock, P, Shikata, M, Shimizu, Y, Simon, H, Sohler, D, Sorlin, O, Stuhl, L, Takeuchi, S, Tanaka, M, Thoennessen, M, Törnqvist, H, Togano, Y, Tomai, T, Tscheuschner, J, Tsubota, J, Uesaka, T, Yang, Z, Yasuda, M, and Yoneda, K

Abstract

The nucleus Ne29 is situated at the border of the island of inversion. Despite significant efforts, no bound low-lying intruder f7/2 state, which would place Ne29 firmly inside the island of inversion, has yet been observed. Here, the first investigation of unbound states of Ne29 is reported. The states were populated in Ne30(p,pn) and Na30(p,2p) reactions at a beam energy of around 230 MeV/nucleon, and analyzed in terms of their resonance properties, partial cross sections, and momentum distributions. The momentum distributions are compared to calculations using the eikonal, direct reaction model, allowing ℓ assignments for the observed states. The lowest-lying resonance at an excitation energy of 1.48(4) MeV shows clear signs of a significant ℓ=3 component, giving first evidence for f7/2 single particle strength in Ne29. The excitation energies and strengths of the observed states are compared to shell-model calculations using the sdpf-u-mix interaction.

Published
2022

2. Extending the Southern Shore of the Island of Inversion to ^{28}F.

Author

Revel, A, Revel, A, Sorlin, O, Marqués, FM, Kondo, Y, Kahlbow, J, Nakamura, T, Orr, NA, Nowacki, F, Tostevin, JA, Yuan, CX, Achouri, NL, Al Falou, H, Atar, L, Aumann, T, Baba, H, Boretzky, K, Caesar, C, Calvet, D, Chae, H, Chiga, N, Corsi, A, Crawford, HL, Delaunay, F, Delbart, A, Deshayes, Q, Dombrádi, Z, Douma, CA, Elekes, Z, Fallon, P, Gašparić, I, Gheller, J-M, Gibelin, J, Gillibert, A, Harakeh, MN, He, W, Hirayama, A, Hoffman, CR, Holl, M, Horvat, A, Horváth, Á, Hwang, JW, Isobe, T, Kalantar-Nayestanaki, N, Kawase, S, Kim, S, Kisamori, K, Kobayashi, T, Körper, D, Koyama, S, Kuti, I, Lapoux, V, Lindberg, S, Masuoka, S, Mayer, J, Miki, K, Murakami, T, Najafi, M, Nakano, K, Nakatsuka, N, Nilsson, T, Obertelli, A, de Oliveira Santos, F, Otsu, H, Ozaki, T, Panin, V, Paschalis, S, Rossi, D, Saito, AT, Saito, T, Sasano, M, Sato, H, Satou, Y, Scheit, H, Schindler, F, Schrock, P, Shikata, M, Shimizu, Y, Simon, H, Sohler, D, Stuhl, L, Takeuchi, S, Tanaka, M, Thoennessen, M, Törnqvist, H, Togano, Y, Tomai, T, Tscheuschner, J, Tsubota, J, Uesaka, T, Yang, Z, Yasuda, M, Yoneda, K, SAMURAI21 collaboration, Revel, A, Revel, A, Sorlin, O, Marqués, FM, Kondo, Y, Kahlbow, J, Nakamura, T, Orr, NA, Nowacki, F, Tostevin, JA, Yuan, CX, Achouri, NL, Al Falou, H, Atar, L, Aumann, T, Baba, H, Boretzky, K, Caesar, C, Calvet, D, Chae, H, Chiga, N, Corsi, A, Crawford, HL, Delaunay, F, Delbart, A, Deshayes, Q, Dombrádi, Z, Douma, CA, Elekes, Z, Fallon, P, Gašparić, I, Gheller, J-M, Gibelin, J, Gillibert, A, Harakeh, MN, He, W, Hirayama, A, Hoffman, CR, Holl, M, Horvat, A, Horváth, Á, Hwang, JW, Isobe, T, Kalantar-Nayestanaki, N, Kawase, S, Kim, S, Kisamori, K, Kobayashi, T, Körper, D, Koyama, S, Kuti, I, Lapoux, V, Lindberg, S, Masuoka, S, Mayer, J, Miki, K, Murakami, T, Najafi, M, Nakano, K, Nakatsuka, N, Nilsson, T, Obertelli, A, de Oliveira Santos, F, Otsu, H, Ozaki, T, Panin, V, Paschalis, S, Rossi, D, Saito, AT, Saito, T, Sasano, M, Sato, H, Satou, Y, Scheit, H, Schindler, F, Schrock, P, Shikata, M, Shimizu, Y, Simon, H, Sohler, D, Stuhl, L, Takeuchi, S, Tanaka, M, Thoennessen, M, Törnqvist, H, Togano, Y, Tomai, T, Tscheuschner, J, Tsubota, J, Uesaka, T, Yang, Z, Yasuda, M, Yoneda, K, and SAMURAI21 collaboration

Abstract

Detailed spectroscopy of the neutron-unbound nucleus ^{28}F has been performed for the first time following proton/neutron removal from ^{29}Ne/^{29}F beams at energies around 230 MeV/nucleon. The invariant-mass spectra were reconstructed for both the ^{27}F^{(*)}+n and ^{26}F^{(*)}+2n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the ^{28}F ground state, with S_{n}(^{28}F)=-199(6) keV, while analysis of the 2n decay channel allowed a considerably improved S_{n}(^{27}F)=1620(60) keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of ^{28}F. Importantly, in the case of the ground state, the reconstructed ^{27}F+n momentum distribution following neutron removal from ^{29}F indicates that it arises mainly from the 1p_{3/2} neutron intruder configuration. This demonstrates that the island of inversion around N=20 includes ^{28}F, and most probably ^{29}F, and suggests that ^{28}O is not doubly magic.

Published
2020

3. Extending the Southern Shore of the Island of Inversion to ^{28}F.

Author

Revel, A, Revel, A, Sorlin, O, Marqués, FM, Kondo, Y, Kahlbow, J, Nakamura, T, Orr, NA, Nowacki, F, Tostevin, JA, Yuan, CX, Achouri, NL, Al Falou, H, Atar, L, Aumann, T, Baba, H, Boretzky, K, Caesar, C, Calvet, D, Chae, H, Chiga, N, Corsi, A, Crawford, HL, Delaunay, F, Delbart, A, Deshayes, Q, Dombrádi, Z, Douma, CA, Elekes, Z, Fallon, P, Gašparić, I, Gheller, J-M, Gibelin, J, Gillibert, A, Harakeh, MN, He, W, Hirayama, A, Hoffman, CR, Holl, M, Horvat, A, Horváth, Á, Hwang, JW, Isobe, T, Kalantar-Nayestanaki, N, Kawase, S, Kim, S, Kisamori, K, Kobayashi, T, Körper, D, Koyama, S, Kuti, I, Lapoux, V, Lindberg, S, Masuoka, S, Mayer, J, Miki, K, Murakami, T, Najafi, M, Nakano, K, Nakatsuka, N, Nilsson, T, Obertelli, A, de Oliveira Santos, F, Otsu, H, Ozaki, T, Panin, V, Paschalis, S, Rossi, D, Saito, AT, Saito, T, Sasano, M, Sato, H, Satou, Y, Scheit, H, Schindler, F, Schrock, P, Shikata, M, Shimizu, Y, Simon, H, Sohler, D, Stuhl, L, Takeuchi, S, Tanaka, M, Thoennessen, M, Törnqvist, H, Togano, Y, Tomai, T, Tscheuschner, J, Tsubota, J, Uesaka, T, Yang, Z, Yasuda, M, Yoneda, K, SAMURAI21 collaboration, Revel, A, Revel, A, Sorlin, O, Marqués, FM, Kondo, Y, Kahlbow, J, Nakamura, T, Orr, NA, Nowacki, F, Tostevin, JA, Yuan, CX, Achouri, NL, Al Falou, H, Atar, L, Aumann, T, Baba, H, Boretzky, K, Caesar, C, Calvet, D, Chae, H, Chiga, N, Corsi, A, Crawford, HL, Delaunay, F, Delbart, A, Deshayes, Q, Dombrádi, Z, Douma, CA, Elekes, Z, Fallon, P, Gašparić, I, Gheller, J-M, Gibelin, J, Gillibert, A, Harakeh, MN, He, W, Hirayama, A, Hoffman, CR, Holl, M, Horvat, A, Horváth, Á, Hwang, JW, Isobe, T, Kalantar-Nayestanaki, N, Kawase, S, Kim, S, Kisamori, K, Kobayashi, T, Körper, D, Koyama, S, Kuti, I, Lapoux, V, Lindberg, S, Masuoka, S, Mayer, J, Miki, K, Murakami, T, Najafi, M, Nakano, K, Nakatsuka, N, Nilsson, T, Obertelli, A, de Oliveira Santos, F, Otsu, H, Ozaki, T, Panin, V, Paschalis, S, Rossi, D, Saito, AT, Saito, T, Sasano, M, Sato, H, Satou, Y, Scheit, H, Schindler, F, Schrock, P, Shikata, M, Shimizu, Y, Simon, H, Sohler, D, Stuhl, L, Takeuchi, S, Tanaka, M, Thoennessen, M, Törnqvist, H, Togano, Y, Tomai, T, Tscheuschner, J, Tsubota, J, Uesaka, T, Yang, Z, Yasuda, M, Yoneda, K, and SAMURAI21 collaboration

Abstract

Detailed spectroscopy of the neutron-unbound nucleus ^{28}F has been performed for the first time following proton/neutron removal from ^{29}Ne/^{29}F beams at energies around 230 MeV/nucleon. The invariant-mass spectra were reconstructed for both the ^{27}F^{(*)}+n and ^{26}F^{(*)}+2n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the ^{28}F ground state, with S_{n}(^{28}F)=-199(6) keV, while analysis of the 2n decay channel allowed a considerably improved S_{n}(^{27}F)=1620(60) keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of ^{28}F. Importantly, in the case of the ground state, the reconstructed ^{27}F+n momentum distribution following neutron removal from ^{29}F indicates that it arises mainly from the 1p_{3/2} neutron intruder configuration. This demonstrates that the island of inversion around N=20 includes ^{28}F, and most probably ^{29}F, and suggests that ^{28}O is not doubly magic.

Published
2020

4. STRUCTURE OF Na-26 VIA A NOVEL TECHNIQUE USING (d, p gamma) WITH A RADIOACTIVE Na-25 BEAM

Author

Catford, WN, Celik, IC, Wilson, GL, Matta, A, Orr, NA, Diget, CA, Adsley, P, Al-Falou, H, Ashley, R, Austin, RAE, Ball, GC, Blackmon, JC, Boston, AJ, Boston, HC, Brown, SM, Cross, DS, Djongolov, M, Drake, TE, Hager, U, Fox, SP, Fulton, BR, Galinski, N, Garnsworthy, AB, Hackman, G, Jamieson, D, Kanungo, R, Leach, K, Martin, J-P, Orce, JN, Pearson, CJ, Porter-Peden, M, Sarazin, F, Sjue, S, Sumithrarachchi, C, Svensson, CE, Triambak, S, Unsworth, C, Wadsworth, R, Williams, SJ, Catford, WN, Celik, IC, Wilson, GL, Matta, A, Orr, NA, Diget, CA, Adsley, P, Al-Falou, H, Ashley, R, Austin, RAE, Ball, GC, Blackmon, JC, Boston, AJ, Boston, HC, Brown, SM, Cross, DS, Djongolov, M, Drake, TE, Hager, U, Fox, SP, Fulton, BR, Galinski, N, Garnsworthy, AB, Hackman, G, Jamieson, D, Kanungo, R, Leach, K, Martin, J-P, Orce, JN, Pearson, CJ, Porter-Peden, M, Sarazin, F, Sjue, S, Sumithrarachchi, C, Svensson, CE, Triambak, S, Unsworth, C, Wadsworth, R, and Williams, SJ

Abstract

States in 26Na were populated in the (d, pγ) reaction, induced by bombarding deuterium target nuclei with an intense reaccelerated beam of 25Na ions from the ISAC2 accelerator at TRIUMF. Gamma-rays were recorded in coincidence with protons and used to extract differential cross sections for 21 states up to the neutron decay threshold of 5 MeV. Results for levels below 3 MeV are discussed in detail and compared with shell model calculations and with previous work. The angular distributions of decay gamma-rays were measured for individual states and are compared to theoretically calculated distributions, highlighting some issues for future work.

Published
2015

5. One- and two-neutron removal reactions from the most neutron-rich carbon isotopes

Author

Kobayashi, N, Nakamura, T, Tostevin, JA, Kondo, Y, Aoi, N, Baba, H, Deguchi, S, Gibelin, J, Ishihara, M, Kawada, Y, Kubo, T, Motobayashi, T, Ohnishi, T, Orr, NA, Otsu, H, Sakurai, H, Satou, Y, Simpson, EC, Sumikama, T, Takeda, H, Takechi, M, Takeuchi, S, Tanaka, KN, Tanaka, N, Togano, Y, Yoneda, K, Kobayashi, N, Nakamura, T, Tostevin, JA, Kondo, Y, Aoi, N, Baba, H, Deguchi, S, Gibelin, J, Ishihara, M, Kawada, Y, Kubo, T, Motobayashi, T, Ohnishi, T, Orr, NA, Otsu, H, Sakurai, H, Satou, Y, Simpson, EC, Sumikama, T, Takeda, H, Takechi, M, Takeuchi, S, Tanaka, KN, Tanaka, N, Togano, Y, and Yoneda, K

Abstract

The structure of 19,20,22C has been investigated using high-energy (around 240 MeV/nucleon) one- and two-neutron removal reactions on a carbon target. Measurements were made of the inclusive cross sections and momentum distributions for the charged residues. Narrow momentum distributions were observed for one-neutron removal from 19C and 20C and two-neutron removal from 22C. Two-neutron removal from 20C resulted in a relatively broad momentum distribution. The results are compared with eikonal-model calculations combined with shell-model structure information. The neutron removal cross sections and associated momentum distributions are calculated for transitions to both the particle-bound and particle-unbound final states. The calculations take into account the population of the mass A−1 reaction residues A−1C and, following one-neutron emission after one-neutron removal, the mass A−2 two-neutron removal residues A−2C. The smaller contributions of direct two-neutron removal, that populate the A−2C residues in a single step, are also computed. The data and calculations are shown to be in good overall agreement and consistent with the predicted shell-model ground-state configurations and one-neutron overlaps with low-lying states in 18−21C. These suggest significant νs1/22 valence neutron configurations in both 20C and 22C. The results for 22C strongly support the picture of 22C as a two-neutron halo nucleus with a dominant νs1/22 ground-state configuration.

Published
2012

6. In-beam spectroscopic studies of the 44S nucleus

Author

Cáceres, L, Sohler, D, Grévy, S, Sorlin, O, Dombrádi, Z, Bastin, B, Achouri, NL, Angélique, JC, Azaiez, F, Baiborodin, D, Borcea, R, Bourgeois, C, Buta, A, Bürger, A, Chapman, R, Dalouzy, JC, Dlouhy, Z, Drouard, A, Elekes, Z, Franchoo, S, Gaudefroy, L, Iacob, S, Laurent, B, Lazar, M, Liang, X, Liénard, E, Mrazek, J, Nalpas, L, Negoita, F, Nowacki, F, Orr, NA, Penionzhkevich, Y, Podolyák, Z, Pougheon, F, Poves, A, Roussel-Chomaz, P, Saint-Laurent, MG, Stanoiu, M, Stefan, I, Cáceres, L, Sohler, D, Grévy, S, Sorlin, O, Dombrádi, Z, Bastin, B, Achouri, NL, Angélique, JC, Azaiez, F, Baiborodin, D, Borcea, R, Bourgeois, C, Buta, A, Bürger, A, Chapman, R, Dalouzy, JC, Dlouhy, Z, Drouard, A, Elekes, Z, Franchoo, S, Gaudefroy, L, Iacob, S, Laurent, B, Lazar, M, Liang, X, Liénard, E, Mrazek, J, Nalpas, L, Negoita, F, Nowacki, F, Orr, NA, Penionzhkevich, Y, Podolyák, Z, Pougheon, F, Poves, A, Roussel-Chomaz, P, Saint-Laurent, MG, Stanoiu, M, and Stefan, I

Published
2012

7. Structure of Al-23 from the one-proton breakup reaction and astrophysical implications

Author

Banu, A, Trache, L, Carstoiu, F, Achouri, NL, Bonaccorso, A, Catford, WN, Chartier, M, Dimmock, M, Fernandez-Dominguez, B, Freer, M, Gaudefroy, L, Horoi, M, Labiche, M, Laurent, B, Lemmon, RC, Negoita, F, Orr, NA, Paschalis, S, Patterson, N, Paul, ES, Petri, M, Pietras, B, Roeder, BT, Rotaru, F, Roussel-Chomaz, P, Simmons, E, Thomas, JS, Tribble, RE, Banu, A, Trache, L, Carstoiu, F, Achouri, NL, Bonaccorso, A, Catford, WN, Chartier, M, Dimmock, M, Fernandez-Dominguez, B, Freer, M, Gaudefroy, L, Horoi, M, Labiche, M, Laurent, B, Lemmon, RC, Negoita, F, Orr, NA, Paschalis, S, Patterson, N, Paul, ES, Petri, M, Pietras, B, Roeder, BT, Rotaru, F, Roussel-Chomaz, P, Simmons, E, Thomas, JS, and Tribble, RE

Published
2011

8. Migration of Nuclear Shell Gaps Studied in the d(Ne-24, p gamma)Ne-25 Reaction

Author

Catford, WN, Timis, CN, Lemmon, RC, Labiche, M, Orr, NA, Fernandez-Dominguez, B, Chapman, R, Freer, M, Chartier, M, Savajols, H, Rejmund, M, Achouri, NL, Amzal, N, Ashwood, NI, Baldwin, TD, Burns, M, Caballero, L, Casadjian, JM, Curtis, N, de France, G, Gelletly, W, Liang, X, Pain, SD, Pucknell, VPE, Rubio, B, Sorlin, O, Spohr, K, Theisen, C, Warner, DD, Catford, WN, Timis, CN, Lemmon, RC, Labiche, M, Orr, NA, Fernandez-Dominguez, B, Chapman, R, Freer, M, Chartier, M, Savajols, H, Rejmund, M, Achouri, NL, Amzal, N, Ashwood, NI, Baldwin, TD, Burns, M, Caballero, L, Casadjian, JM, Curtis, N, de France, G, Gelletly, W, Liang, X, Pain, SD, Pucknell, VPE, Rubio, B, Sorlin, O, Spohr, K, Theisen, C, and Warner, DD

Published
2010

9. Breakup reaction study of the Brunnian nucleus (10)C

Author

Curtis, N, Achouri, NL, Ashwood, NI, Bohlen, HG, Catford, WN, Clarke, NM, Freer, M, Haigh, PJ, Laurent, B, Orr, NA, Patterson, NP, Soic, N, Thomas, JS, Ziman, V, Curtis, N, Achouri, NL, Ashwood, NI, Bohlen, HG, Catford, WN, Clarke, NM, Freer, M, Haigh, PJ, Laurent, B, Orr, NA, Patterson, NP, Soic, N, Thomas, JS, and Ziman, V

Published
2008

10. B(E1) strengths from Coulomb excitation of Be-11

Author

Summers, NC, Pain, SD, Orr, NA, Catford, WN, Angelique, JC, Ashwood, NI, Bouchat, V, Clarke, NM, Curtis, N, Freer, M, Fulton, BR, Hanappe, F, Labiche, M, Lecouey, JL, Lemmon, RC, Mahboub, D, Ninane, A, Normand, G, Nunes, FM, Soic, N, Stuttge, L, Timis, CN, Thompson, IJ, Winfield, JS, Ziman, V, Summers, NC, Pain, SD, Orr, NA, Catford, WN, Angelique, JC, Ashwood, NI, Bouchat, V, Clarke, NM, Curtis, N, Freer, M, Fulton, BR, Hanappe, F, Labiche, M, Lecouey, JL, Lemmon, RC, Mahboub, D, Ninane, A, Normand, G, Nunes, FM, Soic, N, Stuttge, L, Timis, CN, Thompson, IJ, Winfield, JS, and Ziman, V

Published
2007

11. Structure of Be-12: Intruder d-wave strength at N=8

Author

Pain, SD, Catford, WN, Orr, NA, Angelique, JC, Ashwood, NI, Bouchat, V, Clarke, NM, Curtis, N, Freer, M, Fulton, BR, Hanappe, F, Labiche, M, Lecouey, JL, Lemmon, RC, Mahboub, D, Ninane, A, Normand, G, Soic, N, Stuttge, L, Timis, CN, Tostevin, JA, Winfield, JS, Ziman, V, Pain, SD, Catford, WN, Orr, NA, Angelique, JC, Ashwood, NI, Bouchat, V, Clarke, NM, Curtis, N, Freer, M, Fulton, BR, Hanappe, F, Labiche, M, Lecouey, JL, Lemmon, RC, Mahboub, D, Ninane, A, Normand, G, Soic, N, Stuttge, L, Timis, CN, Tostevin, JA, Winfield, JS, and Ziman, V

Published
2006

12. Evidence of a (1d(5/2))(2) component to the Be-12 ground state

Author

Pain, SD, Catford, WN, Orr, NA, Angelique, JC, Ashwood, NI, Bouchat, V, Clarke, NM, Curtis, N, Freer, M, Fulton, B, Hanappe, F, Labiche, M, Lecouey, JL, Lemmon, R, Mahboub, D, Ninane, A, Normand, G, Soic, N, Stuttge, L, Timis, CN, Tostevin, JA, Ziman, V, Winfield, J, Seweryniak, D, Khoo, TL, Pain, SD, Catford, WN, Orr, NA, Angelique, JC, Ashwood, NI, Bouchat, V, Clarke, NM, Curtis, N, Freer, M, Fulton, B, Hanappe, F, Labiche, M, Lecouey, JL, Lemmon, R, Mahboub, D, Ninane, A, Normand, G, Soic, N, Stuttge, L, Timis, CN, Tostevin, JA, Ziman, V, Winfield, J, Seweryniak, D, and Khoo, TL

Abstract

Data have been obtained on exclusive single neutron knockout cross sections from 12Be to study its ground state structure. The cross sections for the production of 11Be in its ground state (1/2 +) and first excited state (0.32 MeV, 1/2 -) have previously been measured, indicating a strong (2s 1 2) 2 component to the 12Be ground state. In the present experiment, performed at the GANIL laboratory, cross sections for the first (0.32 MeV, 1/2 -) and second (1.78 MeV, 5/2 +, unbound) excited states in 11Be were measured, which gives information on the admixture of (1p 1 2) 2 and (1d 5 2) 2 components in the ground state of 12Be. A fragmentation beam of 12Be of ∼10000 pps (95% pure) was incident on a carbon target at 41 MeV/u. The beam particles were tracked onto the target, and their energies were measured event-by-event. The beam-like residues were measured in a position sensitive telescope mounted at zero degrees, and neutrons were measured in the DéMoN array. The 1/2 - state of 11Be was identified by measuring coincident 320 keV γ-rays, using four NaI detectors. Full kinematic reconstruction of unbound states in 11Be was performed using coincident neutrons and 10Be ions. Detailed simulations were performed in order to interpret the data, and spectroscopic factors were calculated, using preliminary single particle removal cross sections calculated using a Glauber model. © 2005 American Institute of Physics.

Published
2005

13. SEARCH FOR DOUBLE GAMOW-TELLER STRENGTH BY HEAVY-ION DOUBLE-CHARGE-EXCHANGE

Author

BLOMGREN, J, LINDH, K, ANANTARAMAN, N, AUSTIN, SM, BERG, GPA, BROWN, BA, CASANDJIAN, JM, CHARTIER, M, CORTINAGIL, MD, FORTIER, S, HELLSTROM, M, JONGMAN, JR, KELLEY, JH, LEPINESZILY, A, LHENRY, I, MACCORMICK, M, MITTIG, W, NILSSON, J, OLSSON, N, ORR, NA, RAMAKRISHNAN, E, ROUSS, BLOMGREN, J, LINDH, K, ANANTARAMAN, N, AUSTIN, SM, BERG, GPA, BROWN, BA, CASANDJIAN, JM, CHARTIER, M, CORTINAGIL, MD, FORTIER, S, HELLSTROM, M, JONGMAN, JR, KELLEY, JH, LEPINESZILY, A, LHENRY, I, MACCORMICK, M, MITTIG, W, NILSSON, J, OLSSON, N, ORR, NA, RAMAKRISHNAN, E, and ROUSS

Abstract

We have carried out a search for double Gamow-Teller excitations, employing the Mg-24(O-18,Ne-18)Ne-24 reaction at 100 and 76 MeV/nucleon at NSCL-MSU and GANIL, respectively, The cross sections for low-lying excitations are typically a few nb/sr, providin, Addresses: BLOMGREN J, UPPSALA UNIV, DEPT NEUTRON RES, BOX 535, S-75121 UPPSALA, SWEDEN. UNIV STOCKHOLM, DEPT PHYS, S-11385 STOCKHOLM, SWEDEN. MICHIGAN STATE UNIV, DEPT PHYS & ASTRON, E LANSING, MI 48824. MICHIGAN STATE UNIV, NATL SUPERCOND CYCLOTRON LAB

Published
1995

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