volume . 004
January 2009

Dear RIBF users
We are sending the 4th issues of the RIBF Quarterly. The past issues are available at our web site:
http://www.nishina.riken.jp/UsersGuide/A Happy New Year !
RIBF made great progress last year. In theuranium-beam experiment by using BigRIPS inNovember, we found more than 20 new neutronrich isotopes whose atomic numbers are from 29 to53 all at once, a result proving the overwhelming
power of RI production at RIBF. In particular, wefound two new neutron rich isotopes of palladium
whose mass numbers are 127 and 128, meaningthat we have reached a magic number nucleus
whose neutron number is 82. There are threepeaks regarded as the isotopes by the r-process
in the distribution in the solar system. Because
this palladium-128 may be one of the origins of thesecond peak, much is anticipated from measuring
the mass and the lifetime precisely using theexperimental facilities of the RIBF.

New Year’s Greetingsfrom the director of Nishina CenterIn the succeeding experiment, we achieved
a calcium-48 beam as strong as 200 pnA, which
impressed overseas expert experimentalists as
the truly the largest intensity in the world.
I heard that some new halo nuclei and many
isomers were found in this series of experiments.
The first half of last year was that of a long andhard struggle. We were pressed by the washingrepair of the helium refrigerator of SRC andBigRIPS contaminated with oil, and the remodelingand the reinforcement of the compressor. We did
not overlook abnormal behavior of the devices,
persuaded manufacturers that it was a bad omenthat may lead to a serious accident, and finally hadthem admit that it was an oversight on the partof the manufacturer side. I deeply admired thepassion and the commitment of the staff of SRC
and BigRIPS who managed to turn the potential
disaster into their advantage.
The Director’s first dream of the New Year are
as follows:

Nishina Center
http://www.nishina.riken.jp/
PAC related
http://www.nishina.riken.jp/UsersGuide/
RIBF User Group
http://ribfwww.riken.go.jp/exp/RIBF_uec_eng/

1) The RI-electron scattering experiment will
start in 2010, about a half century after the stable
nuclei-electron scattering experiment by a Nobel
prize winner, Hofstadter. Now, we will be able
to make a precise measurement of the charge
distribution of unstable nuclei. I am waiting
with great interest the possible outcome of theexperiment. An ISOL-type ion source is necessary
for this experiment. The collaboration between
RIBF and KEK will begin for the development ofthe ion source.

Beam Time Schedule
http://www.nishina.riken.jp/rarfmt/pc.html
Seminar information
http://rarfaxp.riken.jp/~seminar

Nishina Center for Accelerator-Based Science.

.1.

2) The RI-electron scattering equipment can also be
used as a soft X-ray source. With this opportunity,
the collaboration with RIKEN Harima Institute
may start in the usage of synchrotron radiationand the development of a superconducting electronlinac.
3) The new heavy ion linear accelerator, RILACII, will start its operation with a large intensity
28GHz superconducting ECR ion source. Because
the intensity of the uranium-beam increases
drastically with this device, we will find several
hundreds of new isotopes and open the door into a
new aspect of the dark nucleus world.
4) The present RILAC will be able to independently
work non-stop with the operation of RILAC-II.
GARIS-II will also be constructed. The RILAC
facility will become the best facility in the world inthe study of physics and chemistry of superheavy
elements. The next goal is the discovery of a newelement whose atomic number is 126.
The construction of the RIBF is still ongoing.
Let’s pay attention to safety and proceed carefully
without a hurry as we have been doing in the past.
Let’s pay special attention to radiation safety
because the beam intensity of RIBF will increasein the near future.

Toshimi Suda
User Support and Liaison Office
UserSupportOffice@ribf.riken.jp

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January 2009

The world underwent an economic depression
last year. The recent excessively competitive
society seems hollow and lacks sustainable vigor.
We need wisdom in order to avoid our society
from collapsing. The traditional Japanese value,‘harmony is the most precious’, may come backagain. It is important for the leaders to make theright decision at the right time without forgetting
generosity, to enable each researcher to devote towork, and to let everybody contribute the society
in his/her own style.
RIKEN Nishina Center will greet its third
anniversary in coming April. I wish you all thevery best in 2009.

Director of the Nishina Center, Yasushige Yano

Present status, operation schedules of RIBF
BigRIPS/ZD experiments conducted inNovember and December, 2008
- RIBF started its full-scale operation -After successful recovery from the oil
contamination problem (see Quarterly #3), we
conducted the ZeroDegree (ZD) commissioning
and a series of BigRIPS/ZD experiments from thebeginning of November, 2008.
The primary beams were U and 48Ca accelerated
up to 345 AMeV, and their maximum intensitieswere 0.4 and 170 pnA, respectively. The U
beam intensity was improved nearly one order,
and the 48Ca beam power, ~ 2.8 kW, provided toexperiments was the world’s highest. In addition,
the long-term stability of the primary beam has
been remarkably improved.
The ZD commissioning ran first using the Ubeam. Using fission fragments having wide angularand momentum spreads, the optical properties of
the ZD have been carefully measured.
Afterwards, the PAC-approved BigRIPS
experiment, new-isotope search using U beam,
was carried out for one week without any serious
beam off. Several tens of new isotopes in theZ=30 ~ 50 region were unambiguously identified,
one of which was 128Pd that is considered to be oneof key nuclei in the r-process path. We could geta glimpse of this nucleus for the first time using
still “quite faint” U beam of 0.3 pnA compared tothe goal intensity of 1 puA. Much is anticipatedin the future.

Nishina Center
http://www.nishina.riken.jp/
PAC related
http://www.nishina.riken.jp/UsersGuide/
RIBF User Group
http://ribfwww.riken.go.jp/exp/RIBF_uec_eng/
Beam Time Schedule
http://www.nishina.riken.jp/rarfmt/pc.html

A series of experiments using 48Ca-beam, then,followed. To exploit fully the new and precious
opportunity, four experiments, which are formeasuring matter radii, inclusive Coulomb
breakup reaction, and degree of shell-closurein very neutron-rich region, were coordinatedto share their setup and even secondary beams
sometimes.
Based on comparisons with the results ofsimulations and the measured residual activities
at the downstream of the first dipole of theSeminar information
http://rarfaxp.riken.jp/~seminarNishina Center for Accelerator-Based Science.

.2.

BigRIPS, which had been monitored during theexperiments, the in-house safety management
decided on Dec. 21 to terminate the series of 48Ca
experiments. Continuation of the experiments
may cause difficulty to keep the activities in an
acceptable level for engineering works in thebeam-dump area planned in this summer period.
Consequently, the third and forth experiments
mentioned above were unfortunately canceled intheir large and whole parts, respectively, while
their first two experiments could obtain data withthe world’s most powerful 48Ca beam.
The quick-release mechanisms will be fully
installed in BigRIPS this summer, and thenhandling of more intense primary-beams will
become possible.

Beam-time scheduling for the first half of
the FY2009 underway
On Dec. 15, 2008, a call for beam-time requests
has been sent out to all the spokespersons of
the PAC-approved experiments, which targeted
experiments ready to run in the first half of thefiscal year 2009, specifically from April to the endof September. The beam-time schedule will soon
be finalized, and the spokespersons requesting
their beam-time will be contacted accordingly.

Constructions
The construction of a new beam line connecting
the BigRIPS and SHARAQ, which will also beused for dispersion matching purpose, is in thefinal stage.
For the PAC-approved BigRIPS experiments
using light ions such as deuteron, a new beamline connecting RRC directly with SRC whichbypasses IRC is currently being installed. In
this mode, AVF is used as an injector instead ofRILAC. The commissioning will be carried out inthis February.
The first SHARAQ commissioning using these
newly constructed beam lines will be performed in
the end of March.
Toshimi Suda
User Support and Liaison Office
UserSupportOffice@ribf.riken.jp

J a n u a r y

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January 2009

Toward intense primary beams
The installation of a 28 GHz superconducting
ECR ion source is underway as scheduled. Afterthe installation of a new beam line connecting theECR to RILAC, the commissioning will start fromthe beginning of this April. It is expected thatnearly one-order higher intense U-beam, ~ a few
pnA, will be available.

Another intensive activities in the coming
half year will be beam-development efforts. The
acceleration tests of Kr, Xe and U beams including
charge stripper developments will be performed in
the period of February to March, and in June. The
intensities and the stripper lifetime especially for
Kr and Xe will be thoroughly examined.

Reports
PAC meetings
The 4th NP (Nuclear Physics) PAC meeting
was held in Nov. 20-21, 2008, and the submitted
12 proposals were presented and discussed. See
the following web page for details of the PAC
meeting.
http://www.nishina.riken.jp/UsersGuide/NP-PAC
The 4th ML (Material and Life Science) PACmeeting was held in Jan. 13-14, 2009, and thesubmitted 21 proposals (18 for RAL, 3 for RIBF)
were discussed.
http://www.nishina.riken.jp/UsersGuide/ML-PAC

Nishina Center Advisory Council
Prior to RIKEN Advisory
Council (RAC) to be held in April
22-24, 2009, the activities of
Nishina Center for AcceleratorBased Science were reviewed
by the Nishina Center Advisory
Council (NCAC) consisting ofPresident R. Noyori
14 members, chaired by Prof.
S. Gales, GANIL. The followings are the termsof references to NCAC given by the president of
RIKEN, Prof. R. Noyori ;1. Are there achievements with major scientificsignificance or achievements with significant
social impacts ?
2. How does the Nishina Center copare withsimilar research institutions abroad ? Make
recommendations for possible improvement
based on this investigation.
3. Evaluate the Center’s collaborations within
RIKEN and with outside institutions, andevaluate the Center’s effort to promoteinternational collaborations.
The NCAC report will be published later on theinternet.

User Group Activities
The 2nd International Users Group Meeting
was held on Nov. 22 (Sat.), the day after the 4th
NP-PAC meeting. The slides used in the meetingare available at ;http://ribfwww.riken.go.jp/exp/RIBF_uec_eng/
UserMeeting/UserMeeting08/presentation

The minutes of the meeting
preparation by the UEC members.

areunderLecture Series
Two lectures of the Lecture Series on Nuclear Physics have been given as follows. The lecture notes
are available in the following web page.

Nishina Center
http://www.nishina.riken.jp/
PAC related
http://www.nishina.riken.jp/UsersGuide/
RIBF User Group
http://ribfwww.riken.go.jp/exp/RIBF_uec_eng/
Beam Time Schedule
http://www.nishina.riken.jp/rarfmt/pc.html
Seminar information
http://rarfaxp.riken.jp/~seminar

1

Prof. K. Langanke (GSI)“Nuclear Astrophysics”

Nov. 17-18, 2008
http://ribf.riken.jp/~seminar/Lecture/Langanke/index-1.html

2Prof. I. Hamamoto (Lund)“One-particle motion in nuclear many-bodyproblem III”

Dec. 24, 2008
http://ribf.riken.jp/~seminar/Lecture/hamamoto/hamamoto070918-0919/index-1.html

Nishina Center for Accelerator-Based Science.

.3.

Toshimi Suda
User Support and Liaison Office
UserSupportOffice@ribf.riken.jp

J a n u a r y2 0 0 9

volume . 004January 2009

Recent News of RIBF
The FY2008 supplementary budget which
recently passed through the Diet includes those forthe construction of a new injector linac, RILAC-II,and the SCRIT facility, both of which were in thelist of the budgetary request of Nishina Center forthe past few years.

Nishina Center
http://www.nishina.riken.jp/
PAC related
http://www.nishina.riken.jp/UsersGuide/
RIBF User Group
http://ribfwww.riken.go.jp/exp/RIBF_uec_eng/
Beam Time Schedule
http://www.nishina.riken.jp/rarfmt/pc.html
Seminar information
http://rarfaxp.riken.jp/~seminar

Nishina Center for Accelerator-Based Science.

.4.

RILAC-II will make it possible to carry out aseries of super-heavy element search experimentscompletely independent of the BigRIPS experiments
at RIBF. The SCRIT facility will realize electron
scattering off short-lived nuclei for the first time inhuman history. Their construction will start soon,
and will be completed within FY2009.

Toshimi Suda
User Support and Liaison Office
UserSupportOffice@ribf.riken.jp

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