On March 23, 2009, the first beam was successfullytransported to the final focal plane of the SHARAQspectrometer. We investigated detector responses toheavy-ion beams and the ion optical properties ofthe SHARAQ spectrometer1) and the high-resolutionbeam line2) in the subsequent commissioning runs andfound that the system as a whole worked almost as perits design. The first physics run with the spectrometerwas performed in November 2009. In this article, wereview the progress in the SHARAQ project in 2009

Baba, H.

Bazin, Dominique

Fukuda, N.

Ichihara, T.

Inabe, N.

Itahashi, K.

Itoh, S.

Kameda, D.

Kawabata, T.

Kawase, S.

Kubo, T.

Kurei, H.

Kurokawa, M.

Kusaka, K.

Michimasa, S.

Miki, K.

Miya, H.

Nagashima, M.

Nakanishi, K.

Noji, S.

Ohnishi, T.

Ohtake, M.

Ota, S.

P. A. Berg, G.

Roussel-Chomaz, P.

Saito, A.

Sakai, H.

Sasamoto, Y.

Sasano, M.

Shimbara, Y.

Shimizu, Y.

Shimoura, S.

Takeda, H.

Tanaka, K.

Tokieda, H.

Uesaka, T.

Yako, K.

Yamazaki, N.

Yanagisawa, Y.

Yoshida, A.

Yoshida, K.

Yoshino, A.

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SHARAQ Project: Progress in 2009T. Uesaka, S. Michimasa, S. Ota, A. Saito, K. Nakanishi, Y. Sasamoto, H.Miya, H. Tokieda, S. Kawase, Y. Shimizu, et al.To cite this version:T. Uesaka, S. Michimasa, S. Ota, A. Saito, K. Nakanishi, et al.. SHARAQ Project: Progressin 2009. RIKEN Accelerator Progress Report, 2010, 43, pp.179-170. <in2p3-00552005>HAL Id: in2p3-00552005http://hal.in2p3.fr/in2p3-00552005Submitted on 5 Jan 2011HAL is a multi-disciplinary open accessarchive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come fromteaching and research institutions in France orabroad, or from public or private research centers.L’archive ouverte pluridisciplinaire HAL, estdestine´e au de´poˆt et a` la diffusion de documentsscientifiques de niveau recherche, publie´s ou non,e´manant des e´tablissements d’enseignement et derecherche franc¸ais ou e´trangers, des laboratoirespublics ou prive´s.RIKEN Accel. Prog. Rep. 43 (2010)SHARAQ Project: Progress in 2009T. Uesaka,∗1 S. Michimasa,∗1 S. Ota,∗1 A. Saito,∗1 K. Nakanishi,∗1 Y. Sasamoto,∗1 H. Miya,∗1 H. Tokieda,∗1S. Kawase,∗1 Y. Shimizu,∗1 S. Shimoura,∗1 K. Miki,∗2 S. Noji,∗2 H. Sakai,∗2 K. Yako,∗2 S. Itoh,∗2 H. Kurei,∗1N. Yamazaki,∗1 A. Yoshino,∗1 T. Kawabata,∗4 Y. Yanagisawa,∗3 T. Kubo,∗3 T. Ohnishi,∗3 H. Takeda,∗3D. Kameda,∗3 N. Fukuda,∗3 K. Tanaka,∗3 K. Yoshida,∗3 A. Yoshida,∗3 N. Inabe,∗3 K. Kusaka,∗3 M. Ohtake,∗3M. Kurokawa,∗3 M. Sasano,∗3 K. Itahashi,∗3 H. Baba,∗3 T. Ichihara,∗3 Y. Shimbara,∗5 M. Nagashima,∗5G. P. A. Berg,∗6 D. Bazin,∗7 and P. Roussel-Chomaz,∗8On March 23, 2009, the ﬁrst beam was successfullytransported to the ﬁnal focal plane of the SHARAQspectrometer. We investigated detector responses toheavy-ion beams and the ion optical properties ofthe SHARAQ spectrometer1) and the high-resolutionbeam line2) in the subsequent commissioning runs andfound that the system as a whole worked almost as perits design. The ﬁrst physics run with the spectrometerwas performed in November 2009. In this article, wereview the progress in the SHARAQ project in 2009.1 Last minutes of the constructionThe construction of the spectrometer and the beamline was continued until the end of February 2009.Cathode read-out drift chambers (CRDC) were in-stalled at the focal plane of the SHARAQ spectrometerin January 2009. The vacuum chambers and pumpingsystems of the spectrometer were built in February.Fig. 1. Newly constructed beam line magnets: two normal-conducting dipole magnets (DH7 and DH8) and a su-perconducting triplet quadrupole magnet(STQ-H15).Two normal conducting dipole magnets with a bend-ing angle of 30◦, vacuum chambers for beam line de-∗1 Center for Nuclear Study (CNS), University of Tokyo∗2 Department of Physics, University of Tokyo∗3 RIKEN Nishina Center∗4 Kyoto University∗5 Niigata University∗6 University of Notre Dame∗7 National Superconducting Cyclotron Laboratory, MichiganState University∗8 GANILtectors, and vacuum pumps were installed in the high-resolution beam line in February 20093). Figure 1shows a photograph of the newly constructed beam-line magnets: two normal-conducting dipole mag-nets (DH7 and DH8) and a superconducting tripletquadrupole magnet(STQ-H15).2 Commissioning runsA primary 14N beam accelerated up to 250 MeV inSRC was transported from F0 of BigRIPS to the focalplane of the SHARAQ spectrometer. This is the ﬁrsttime that a beam was accelerated without involving anIRC. The ion beam struck plastic scintillation countersplaced downstream of the focal plane for the ﬁrst timeat 22:37 on March 23, 2009 (JST).The beam-line detectors consisting of eight multi-wire drift chambers (MWDC) and the SHARAQ focal-plane CRDCs were irradiated by the 14N beam andthe secondary beams of 12B, 9Li, 6He, and 3H at200A MeV. The detectors were operated at a low gaspressure of 10 kPa for the beam-line MWDCs and at2 kPa for the CRDCs. Detection eﬃciencies were foundto be almost 100% even for light ions with Z in therage 1–76,7). We have also conﬁrmed that position res-olutions are high and amount to 200–300 µm FWHM,which meets the design requirements. A new data tak-ing system was also found to function satisfactorily.The ion-optical properties of the magnetic systemwere investigated by using beam trajectories deter-mined by the tracking detectors described above. Mo-mentum dispersions (x|δ) at the dispersive focal planesF6 and FH7 and at the focal plane of the SHARAQspectrometer were found to be 7.8 m, 7.5 m and 5.8 m,respectively. These values are consistent with the de-sign values.Beam-line tuning was carried out to achieve lateraland angular dispersion matching conditions and dou-ble focus conditions at the SHARAQ target position4);the tuning was performed by adjusting the excitationcurrents of the four quadrupoles QH18, STQH19a, b,and c. During the tuning, the correlations betweenparticle trajectories at the dispersive focal plane FH7and at the focal plane of the SHARAQ spectometerwere used for diagnostics. The beam position at FH7,xFH7, corresponds to the beam momentum, and thus,the correlation between xFH7 and the position in the1- 168 - - 169 - cc l. rog. Re .  (2010)focal plane of the SHARAQ spectrometer, xFP, pro-vides a good measure of (x|δ) of the whole ion-opticalsystem. The upper panel of Fig. 2 shows the correla-tion between xFH7 and xFP. The upright correlationbetween xFH7 and xFP in the ﬁgure clearly shows thatthe beam position at the focal plane of the SHARAQspectrometer is independent of the beam momentum,which indicates the achievement of the lateral disper-sion matching condition.-40-30-20-10010203040-20 0 20xFP [mm]δp/p0.2%x FH7 [mm]-40-30-20-10010203040-20 0 20x FH7 [mm]aFP [mrad]Fig. 2. Horizontal beam images at the ﬁnal focal plane inthe achromatic (upper panel) and the dispersion match-ing transport (lower panel).Similarly, the correlation between xFH7 and the hor-izontal angle at the focal plane of the SHARAQ spec-trometer, aFP, that is shown in the lower panel of Fig. 2is a good measure of the angular dispersion matching.After tuning, we succeeded in obtaining the lateraland angular dispersion matching conditions simulta-neously.Figure 3 shows the horizontal beam image at thefocal plane of the SHARAQ spectrometer. Its widthcorresponds to the intrinsic momentum resolution ofthe ion-optical system. The upper panel presents thedata obtained in the achromatic transport mode. Inthis mode, the resolution was limited by the momen-tum spread of the beam. After the dispersion matchingcondition was obtained by carrying out beam line tun-ing, the beam image was narrowed down considerably,as shown in the lower panel of Fig. 3.The resulting momentum resolution δp/p was foundto be approximately 8100. Further studies to im-prove the momentum resolution are in progress. Fromthe ion-optical studies, it is clearly demonstrated thattracking of the beam particles in the beam line facil-itates beam line tuning that is required to obtain thedispersion matching conditions.50100150200250300Achromatic transport0−40 −30 −20 −10 0 10 20 30 40Position at Focal Plane [mm]May/09 dispersion matched !p/δp= 81000250500750100012501500175020002250Fig. 3. Horizontal beam images at the ﬁnal focal plane inthe achromatic transport mode (upper panel) and inthe dispersion matched transport mode (lower panel).3 The (t, 3He) ExperimentThe ﬁrst physics run with the SHARAQ spectrome-ter was performed to search for β+-type isovector spinmonopole resonances in 90Zr and 208Pb. The (t, 3He)reaction at 300 MeV/nucleon was used to extract β+strengths. An intense triton beam of 107 s−1 was pro-duced by projectile fragmentation of a primary 320-MeV/nucleon 4He beam, and the scattered 3He ionswere momentum-analyzed by the SHARAQ spectrom-eter. The details of the experiment are described inRef. 8.References1) T. Uesaka et al.: Nucl. Instrum. Methods B 266, 4218(2008).2) T. Kawabata et al.: Nucl. Instrum. Methods B 266,4201 (2008).3) Y. Yanagisawa et al.: Bull. Amer. Phys. Soc. 54, 48(2009).4) Y. Sasamoto et al.: RIKEN Acc. Prog. Rep. 43 (2010).5) S. Michimasa et al.: RIKEN Acc. Prog. Rep. 43 (2010).6) A. Saito et al.: RIKEN Acc. Prog. Rep. 43 (2010).7) H. Miya et al.: RIKEN Acc. Prog. Rep. 43 (2010).8) K. Miki et al.: RIKEN Acc. Prog. Rep. 43 (2010).2- 170 - - 171 -

SHARAQ Project: Progress in 2009

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RIKEN Accel. Prog. Rep. 43 (2010)SHARAQ Project: Progress in 2009T. Uesaka,∗1 S. Michimasa,∗1 S. Ota,∗1 A. Saito,∗1 K. Nakanishi,∗1 Y. Sasamoto,∗1 H. Miya,∗1 H. Tokieda,∗1S. Kawase,∗1 Y. Shimizu,∗1 S. Shimoura,∗1 K. Miki,∗2 S. Noji,∗2 H. Sakai,∗2 K. Yako,∗2 S. Itoh,∗2 H. Kurei,∗1N. Yamazaki,∗1 A. Yoshino,∗1 T. Kawabata,∗4 Y. Yanagisawa,∗3 T. Kubo,∗3 T. Ohnishi,∗3 H. Takeda,∗3D. Kameda,∗3 N. Fukuda,∗3 K. Tanaka,∗3 K. Yoshida,∗3 A. Yoshida,∗3 N. Inabe,∗3 K. Kusaka,∗3 M. Ohtake,∗3M. Kurokawa,∗3 M. Sasano,∗3 K. Itahashi,∗3 H. Baba,∗3 T. Ichihara,∗3 Y. Shimbara,∗5 M. Nagashima,∗5G. P. A. Berg,∗6 D. Bazin,∗7 and P. Roussel-Chomaz,∗8On March 23, 2009, the ﬁrst beam was successfullytransported to the ﬁnal focal plane of the SHARAQspectrometer. We investigated detector responses toheavy-ion beams and the ion optical properties ofthe SHARAQ spectrometer1) and the high-resolutionbeam line2) in the subsequent commissioning runs andfound that the system as a whole worked almost as perits design. The ﬁrst physics run with the spectrometerwas performed in November 2009. In this article, wereview the progress in the SHARAQ project in 2009.1 Last minutes of the constructionThe construction of the spectrometer and the beamline was continued until the end of February 2009.Cathode read-out drift chambers (CRDC) were in-stalled at the focal plane of the SHARAQ spectrometerin January 2009. The vacuum chambers and pumpingsystems of the spectrometer were built in February.Fig. 1. Newly constructed beam line magnets: two normal-conducting dipole magnets (DH7 and DH8) and a su-perconducting triplet quadrupole magnet(STQ-H15).Two normal conducting dipole magnets with a bend-ing angle of 30◦, vacuum chambers for beam line de-∗1 Center for Nuclear Study (CNS), University of Tokyo∗2 Department of Physics, University of Tokyo∗3 RIKEN Nishina Center∗4 Kyoto University∗5 Niigata University∗6 University of Notre Dame∗7 National Superconducting Cyclotron Laboratory, MichiganState University∗8 GANILtectors, and vacuum pumps were installed in the high-resolution beam line in February 20093). Figure 1shows a photograph of the newly constructed beam-line magnets: two normal-conducting dipole mag-nets (DH7 and DH8) and a superconducting tripletquadrupole magnet(STQ-H15).2 Commissioning runsA primary 14N beam accelerated up to 250 MeV inSRC was transported from F0 of BigRIPS to the focalplane of the SHARAQ spectrometer. This is the ﬁrsttime that a beam was accelerated without involving anIRC. The ion beam struck plastic scintillation countersplaced downstream of the focal plane for the ﬁrst timeat 22:37 on March 23, 2009 (JST).The beam-line detectors consisting of eight multi-wire drift chambers (MWDC) and the SHARAQ focal-plane CRDCs were irradiated by the 14N beam andthe secondary beams of 12B, 9Li, 6He, and 3H at200A MeV. The detectors were operated at a low gaspressure of 10 kPa for the beam-line MWDCs and at2 kPa for the CRDCs. Detection eﬃciencies were foundto be almost 100% even for light ions with Z in therage 1–76,7). We have also conﬁrmed that position res-olutions are high and amount to 200–300 µm FWHM,which meets the design requirements. A new data tak-ing system was also found to function satisfactorily.The ion-optical properties of the magnetic systemwere investigated by using beam trajectories deter-mined by the tracking detectors described above. Mo-mentum dispersions (x|δ) at the dispersive focal planesF6 and FH7 and at the focal plane of the SHARAQspectrometer were found to be 7.8 m, 7.5 m and 5.8 m,respectively. These values are consistent with the de-sign values.Beam-line tuning was carried out to achieve lateraland angular dispersion matching conditions and dou-ble focus conditions at the SHARAQ target position4);the tuning was performed by adjusting the excitationcurrents of the four quadrupoles QH18, STQH19a, b,and c. During the tuning, the correlations betweenparticle trajectories at the dispersive focal plane FH7and at the focal plane of the SHARAQ spectometerwere used for diagnostics. The beam position at FH7,xFH7, corresponds to the beam momentum, and thus,the correlation between xFH7 and the position in the1- 168 - - 169 - cc l. rog. Re .  (2010)focal plane of the SHARAQ spectrometer, xFP, pro-vides a good measure of (x|δ) of the whole ion-opticalsystem. The upper panel of Fig. 2 shows the correla-tion between xFH7 and xFP. The upright correlationbetween xFH7 and xFP in the ﬁgure clearly shows thatthe beam position at the focal plane of the SHARAQspectrometer is independent of the beam momentum,which indicates the achievement of the lateral disper-sion matching condition.-40-30-20-10010203040-20 0 20xFP [mm]δp/p0.2%x FH7 [mm]-40-30-20-10010203040-20 0 20x FH7 [mm]aFP [mrad]Fig. 2. Horizontal beam images at the ﬁnal focal plane inthe achromatic (upper panel) and the dispersion match-ing transport (lower panel).Similarly, the correlation between xFH7 and the hor-izontal angle at the focal plane of the SHARAQ spec-trometer, aFP, that is shown in the lower panel of Fig. 2is a good measure of the angular dispersion matching.After tuning, we succeeded in obtaining the lateraland angular dispersion matching conditions simulta-neously.Figure 3 shows the horizontal beam image at thefocal plane of the SHARAQ spectrometer. Its widthcorresponds to the intrinsic momentum resolution ofthe ion-optical system. The upper panel presents thedata obtained in the achromatic transport mode. Inthis mode, the resolution was limited by the momen-tum spread of the beam. After the dispersion matchingcondition was obtained by carrying out beam line tun-ing, the beam image was narrowed down considerably,as shown in the lower panel of Fig. 3.The resulting momentum resolution δp/p was foundto be approximately 8100. Further studies to im-prove the momentum resolution are in progress. Fromthe ion-optical studies, it is clearly demonstrated thattracking of the beam particles in the beam line facil-itates beam line tuning that is required to obtain thedispersion matching conditions.50100150200250300Achromatic transport0−40 −30 −20 −10 0 10 20 30 40Position at Focal Plane [mm]May/09 dispersion matched !p/δp= 81000250500750100012501500175020002250Fig. 3. Horizontal beam images at the ﬁnal focal plane inthe achromatic transport mode (upper panel) and inthe dispersion matched transport mode (lower panel).3 The (t, 3He) ExperimentThe ﬁrst physics run with the SHARAQ spectrome-ter was performed to search for β+-type isovector spinmonopole resonances in 90Zr and 208Pb. The (t, 3He)reaction at 300 MeV/nucleon was used to extract β+strengths. An intense triton beam of 107 s−1 was pro-duced by projectile fragmentation of a primary 320-MeV/nucleon 4He beam, and the scattered 3He ionswere momentum-analyzed by the SHARAQ spectrom-eter. The details of the experiment are described inRef. 8.References1) T. Uesaka et al.: Nucl. Instrum. Methods B 266, 4218(2008).2) T. Kawabata et al.: Nucl. Instrum. Methods B 266,4201 (2008).3) Y. Yanagisawa et al.: Bull. Amer. Phys. Soc. 54, 48(2009).4) Y. Sasamoto et al.: RIKEN Acc. Prog. Rep. 43 (2010).5) S. Michimasa et al.: RIKEN Acc. Prog. Rep. 43 (2010).6) A. Saito et al.: RIKEN Acc. Prog. Rep. 43 (2010).7) H. Miya et al.: RIKEN Acc. Prog. Rep. 43 (2010).8) K. Miki et al.: RIKEN Acc. Prog. Rep. 43 (2010).2- 170 - - 171 -

SHARAQ Project: Progress in 2009

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