Minutes of the 61st Machine-Time Committee Meeting
Date and time: December 21, 2012; 13:30–15:35
Place: RIBF Bldg., Room 203a

Attendees: Sakai (Chair), Aoi
ad, †, ‡, En’yo

Morita , Motobayashia, †aba, †a, Fukunishi , Haba, Nishimura

Wakasugi , Yamaguchi , Hirayama
A. Yoshidaaa, †c, †a, †aaa, Kamigaito , Kase , Kubo , Miyatakeabaac, †,a, Sakurai , Shimoura , Ueno , Uesaka , Uwamino ,, Inabea, †, Kajia, †, Morimoto

RIBF-UEC /†‡, Imaoa, †a, †, Yakod, †,a, †Absent: Abe , K. Yoshidaa, †a

RNC /bc

CNS / KEK /dObserver /TV Attendee(in random order)
Reports
1.

Changes of the beam-time schedule (Ueno)
It was reported that the schedule of the beam time (BT) of the 238U beam series had been revised onNovember 18 and 22 due to the delays in beam delivery. It was also determined on December 5 toextend the series by 10 days from December 8, the last day as originally scheduled. Details of themodification are summarized below.
Exp.-Prog.-Num.
RILAC:MS-EXP12-07 (Kuboki)previous
Dec 8, 9:00

– Dec 10, 9:00

changed→suspended

SRC:
NP0802 -RIBF60&62R-01 (Watanabe) Nov 16, 21:00 –Nov 27, 21:00 –NP1112-RIBF85-01 (Simpson)
NP0802 -RIBF60&62R-02 (Watanabe) Dec 2, 21:00 –MS-ACC12-09 (Fukunishi)
Nov 27, 21:00 –MS-EXP12-04 (Kubo)
NP1112-RIBF90-01 (Niikura)2.

Nov 23, 9:00 → Nov 16, 21:00 –Dec 2, 21:00 → Nov 30, 21:00 –Dec 8, 9:00
→ Dec 5, 12:00 –(newly scheduled) Dec 9, 21:00 –Dec 2, 21:00 → Dec 11, 10:50 –(newly scheduled) Dec 12, 9:00 –Nov 29, 21:00
Dec 5, 12:00
Dec 9, 21:00
Dec 11, 10:50
Dec 12, 9:00
Dec 18, 9:00

Report on the RIBF accelerator operation – the 238U beam delivery (Fukunishi)
In the 238U86+ beam series of the BigRIPS-based experiments, the beam was delivered from 0:52 on
November 5 to 9:03 on December 18 with only 4 hours delay from the original BT schedule including a
10 days extension. Despite a temporary suspension due to a full-scale accelerator tuning on Nov. 7,tuning of the power-supply system feeding the fRC main coil on Nov. 14, a repair of RRC-EDC meltedby the beam, and the replacement of the ion-source material and the beam re-acceleration from Nov. 18
to 23, the stability and sustainability of the beam delivery increased continuously at a high level, In thebeginning of the series, the reliability of the accelerator system was R = 71% and an average beam
current was Iav = 6.7 pnA, where R is defined by R = T1/T2 with T1 being the time in which the beam canbe delivered from the accelerator if requested by the users, and T2 the scheduled BT. Both the reliability
and the current were increased to R = 86% and Iav = 11 pnA following the replacement of the ion-source
material and re-acceleration. It was noted that these values were as high as R = 94% and Iav = 12.2 pnA,

in particular, during the extended last 10 days. Furthermore, the instantaneous maximum beam current
15.1 pnA was recorded in this 238U series which should be compared with 3.8 pnA, the maximum current
achieved last year. It was also reported that an overall R achieved in 2012 was 85.9% which shows asignificant increase from R = 68.2% in 2008.
3.

Status of the BT scheduling for the first half of FY2013 (Ueno)
It was reported that following the decision made at the previous meeting, the BT scheduling process forthe first half of FY2013, including BTs of AVF, RILAC, and RRC for February and March, 2013, started
two months earlier than the regular schedule.. A tentative schedule is as follows:
Nov. 16:

60th MT Committee Meeting (screening of MS proposals and discussions on thebeam plan for BigRIPS-based experiments for the first half of FY2013)

Nov. 19–Dec. 11: Call for BT Scheduling Requests (February–March + first half of FY2013)
Dec. 11–25:

BT scheduling by the User Liaison Team (Dec. 21: 61st MT Committee Meeting)Dec. 25–Jan. 14:

Submission of the Accelerator-Use Planning Sheets (AUPSs) in parallel with theBT schedulingJan. 14–Jan. 23:

Documentary review of AUPSs by the Safety Review Committee, in parallelwith the final adjustment of the BT schedule

Jan. 24:

Safety Review Committee Meeting

Jan. 25:

62nd MT Committee Meeting (approval of the BT schedule)

Topics discussed
1. Approval of the minutes of the previous meeting (Sakai)
2. Review of BT requests in the Machine Study and Detector Development categories (Sakai)
New BT requests for the first half of FY2013 in the Machine Study (MS) and Detector Development(DD) categories were reviewed through interviews and presentations by the representatives. After
discussions, it was determined that the following requests be approved. The BT scheduling for thesehowever, was discussed separately from this approval.
Category
DDMS-EXP

Spokesperson
Kim(Yamaguchi)
A. Yoshida

BeamCRIB

15N

7CRIB

22Ne

6.1

56

MS-EXP

Hirayama

KISS

MS-EXP

KajiGARIS-II

Fukunishi

SRC

*2*1
*2

Current(pnA)

Request(days)

Result≥ 600

2Approved

300

12Approved

Fe90

10Ne

5.8

≥10,000

5.8≥1,000400

1,000

22MS-ACC

E/A(MeV)

Device

48

Ca

40

Ar

Approved

2

Conditionally*1
Approved

2

Approved

2Approved

7–

The proposal will be reviewed again depending on the result of the first MS is conducted.
MS-ACC is the category set for the beam-acceleration tests by the Accelerator Group. The programs in this category as well as the beam
acceleration in the usual accelerator operation are not required to be reviewed by the MT Committee and the Safety Committee. MS-EXP isthe category for other R&D studies of a basic component regarded as a key device of the RIBF facility. These BTs are not open to users.

3. Official BTs provided to the BigRIPS-based experiments in November–December (Sakai)

Details of the BT statistics in the experiments using a 238U beam conducted from November to December
were reported (Ueno). After discussions, the official BTs provided from the facility to each experimental
program were set as follows:–

NP0702-RIBF10 (Nishimura) :7.5 days–

NP0802-RIBF60&62R1 (Watanabe/Lorusso) : 10 days–

NP1112-RIBF85 (Simpson) :5 days–

NP1112-RIBF90 (Niikura) :5.5 days

4. BT schedule for January, 2013 (Sakai)
All BTs of the BigRIPS-based experiments scheduled for FY2012 were completed in December, 2012. A
modification plan of the BT schedule for January was discussed, to prepare for immediate actions to betaken if the operation of the new RIBF facilities such as BigRIPS and SRC are to become possible. The
possibility of operation will mostly depend on electricity and budgetary constraints, which should besolved by discussing with the RIKEN Headquarters. Thus, the modification cannot be approved by theMT Committee only. Since this issue cannot be carried over to the next meeting due to the tight schedule,
the decision on the BT modification was left to the discretion of the MT Committee Chair. In order toavoid confusion, the RRC-use experiments scheduled for the end of January were shifted to February inadvance.
5. BT schedule for the FY2013 first half (Sakai)As provided in the above Report 3, the BT scheduling for the first half of FY2013 (from February to theend of September, 2013 to be precise) is underway. The latest BT plan, shown by the User Liaison Team,was discussed. After further optimization is examined based on discussions at the meeting, a tentative BT
plan will be disclosed by the end of December. Then, the following two weeks will be used for adjusting
and finalizing the BT schedule. In parallel with this, the procedure to review safety aspects of theexperiments by the Safety Review Committee will start. The BT plan will be fixed after the approval by
the MT Committee at the next meeting in January.
6. Management of new isotope data obtained with BigRIPS (Sakai)“Guideline for the operation of BigRIPS experiments” which stipulates the roles of experimenters, theBigRIPS Team, and the Accelerator Group has been in force since November 24, 2009. To publish thefindings of new isotopes as well as cross sections of secondary beams promptly, both of which areimportant missions of RIBF, by setting up a close relationship between experimenters and the BigRIPS
Team, the MT Committee Chair proposed to revise the guideline following the basic principles given
below:
1) All data obtained at RIBF will belong to RNC. Therefore, the RNC director has a right to theiraccess.
2) The experimenters can access the data freely. They have rights and duties to analyze and publish
the data.

3) Based on the rights provided in 1), a part of the data concerning the findings of new isotopes
obtained by experimenters will be analyzed as soon as possible by those at RNC who has
expertise in the field, i.e., the BigRIPS Team in most cases.(as such, they will be considered to be
in charge hereon). The results will be published in collaboration with the experimenters. However,this is not the case when–a spectrum showing particle identifications in a paper written by the experimenters suggests
the existence of new isotopes, and–analysis and publication of the new isotope data by the experimenters are faster than thesame done by the BigRIPS Team.

4) The new guideline will be put into operation according to an agreement among the experiment
spokesperson, the BigRIPS Team, and the ULIC group director. Tripartite meeting will be heldfor each experiment.
5) When the BigRIPS Team is registered as collaborators independently of 3), the need for / role inthe collaborative research should be made clear by setting up close relationships between
experimenters and the BigRIPS Team clear.
It was suggested that this new guideline should not be extended to the new isotopes discovered in thesecondary reaction studies, e.g., using the ZD spectrometer (Aoi and En’yo). Further discussions will beconducted by a WG consisting of Sakai, Ueno, Aoi, Yoshida, Inabe, Nishimura, and Kubo as members.
Moreover, the UEC Chair was asked to have the original guideline confirmed by RIBF users.
7. Priority of the kind of heavy ions to be developed (Sakai)Discussion on beams to be developed after 238U (1st priority) and 48Ca (2nd priority) carried over from theprevious meeting ensued. The priorities of Ti, Ge, Cr beams were determined as 3rd, 4th, and 5th,respectively.
8. Next meetings
The next meeting will be held on Friday, January 25, 2013, at 13:30.

The meeting after the next will be held on Friday, February 15, 2013, at 13:30.