Minutes of the 53rd Machine-Time Committee Meeting
Date and time: March 16, 2012; 13:30–14:50
Place: RIBF Bldg., Room 203
Attendees: Sakaiaa(Chair), Abe , En’yo

Motobayashia, †a, Nishimuraaa, †a, †, Sudaa, Fukunishi , Habac, †, ‡b

Absent: Kamigaito , Sakurai , Shimoura , Yoshidaaaa, †aaba, Kase , Kubo , Kubono , Morita ,aaa, Ueno , Uesaka , Uwamino , Wakasugi , Yamaguchib, †a, †RNC /b

CNS /cRIBF-UEC /†Observer /‡TV Attendee(in random order)
Reports
1.

Change of the beam time schedule (Ueno)
Due to trouble of RILAC, the start of ML1006-LINAC27-02 (Haba) was delayed for 1.3 days. After adelay of one day, it ended on March 9 at 9:00. After a delay of 1.2 days, the subsequent beam time (BT)of NP0702-LINAC12-14 (Morita) started on March 13 at 14:46. The other BTs scheduled for last month
were conducted as planned.

2.

RIBF operation (Fukunishi)
Conditions of RRC during the BT of NP0912-RIBF34-02 (Sekiguchi)
It was announced in the last meeting that the suspension of BT schedule for the urgent repair of RRC
will be determined depending on the condition of RRC during this BT. Fortunately, there was noserious trouble resulting from the layer-short problem of RRC in the accelerator tuning for the beamdelivery. The BT was completed as scheduled. Still with the risk of RRC trouble, the operation ofRIBF will be continued until RRC is repaired in August.

Status of the 18O beam delivery
The accelerator tuning for the beam delivery was quite smooth. It was completed ahead of theschedule. The beam current was 250–500 pnA, which was higher than requested. The beam energy
will be changed from E/A = 300 to 230 MeV in the second half of the 18O beam series. This is thelowest energy ever been delivered by SRC. Its beam current was not mentioned due to the lack ofreference data.

3.

Official facility inspection of SAMURAI (Uwamino)
The on-site official facility inspection requested in last May and December regarding the application formodification approval of radiation facilities was carried out and approved. This modification enables usto use four areas, BigRIPS main room, SAMURA, ZD, EURICA, as separated radiation controlled areasfrom each other: Experimenters could have access to these areas even during a BT if a beam is notdelivered to the site.

4.

Status of the maintenance and construction of BigRIPS/SAMURAI (Kubo)
The construction of SAMURAI and a related beam line have been completed. The BT for the firstcommissioning in the Machine Study (MS) category has started today since 13:00.

A new movable base has been equipped with STQ-18 for the switchover of the downstream beam

line of BigRIPS between ZD and SAMURAI. A typical operation time required for the switchoversystem is 0.5 days. In addition, STQ-25 has been newly installed at 4 m upstream of SAMURAI.
A quench of STQ-1 occurred unexpectedly when the training of the BigRIPS superconducting
magnets was performed as usual. Although its recovery took time because a compressor was also
halted by this quench, the BT schedule was not delayed.

5.

Status of EURICA installation/maintenance (Nishimura)
A pipe to carry liquid N2 from B3F to F11 and a reservoir tank at F11 will be installed in a short time
period from just after the SAMURAI commissioning (MS11-10) up to the start of the first EURICA
commissioning scheduled to start from March 28 (MS11-17).

6.

Change of MT Committee members (Sakai)
Following the retirement of Professor Kubono from CNS, the University of Tokyo in March, 2012, Dr.
Yamaguchi, who is a Lecturer of CNS, the University of Tokyo, was appointed by the RNC director
En’yo as a new MT Committee member from April in accordance with the Article 4–(9) of RIBF MTCommittee Bylaws. This appointment was based on an agreement between RNC and CNS at theCNS–RIKEN Research Collaboration Liaison Meeting.

7.

FY2012 first half year BT schedule (Ueno)
The BT plan approved by the MT Committee in the previous meeting was disclosed to the relevant
representatives. The subsequent week was spent making adjustments by taking into account theircomments, and in the end, there were no further corrections made on the BT plan. It was announced
that the SRC-use BTs scheduled for July has been scheduled as tentative BTs until the electricity
supply situation in the summer becomes clear.

The In-House Safety Committee meeting was held on March 13 on the BTs that have beenscheduled based on the Accelerator-Use Planning Sheets (AUPS) submitted from the representatives.
They were requested to make improvements on their experimental plan with regard to the matterspointed out by the Committee by the end of March.

The Accelerator Group requested that MSs which only conduct test of beam delivery without any
additional experimental devices should be excluded from the safety review by the Safety Committee
since in such MSs, the accelerators are operated in the same mode as a normal accelerator
operation.*1 (Fukunishi)*1

8.

After the meeting, the request was discussed among the RNC Safety Management Group Director, Radiation
Protection Liaison Officer, and Substitute Radiation Protection Liaison Officer. The request was accepted(Uwamino). However, for the purpose of BT information management, a new form, in which only information on
the beam and the representative are indicated, will be prepared instead of AUPS (Ueno).

Status of PAC meetings (Ueno)
11th NP-PAC (June 18–19): The call-for-proposals was sent out on March 15 (submission deadline isMay 2). The number of BT days requested in the cover page of proposals has been modified to reflect
the decision made at the 51st MT Committee Meeting. Moreover, Dr. Doornenbal has been assigned
as the detector contact person of DALI2.



9th ML-PAC & 3rd In-PAC: under preparation

Topics discussed
1. Approval of the minutes of the previous meeting (Sakai)
2. Modification of NP1012-SHARAQ06 (Sakai)
A representative proposed to modify NP1012-SHARAQ06 to conduct a by-product measurement throughanother reaction by inserting an additional target at the position of SHARAQ-FH9 in parallel with themeasurement of reaction, the main purpose of the experiment, approved by PAC (Yako). While theCommittee agreed that the result from the by-product measurement is useful for the main purpose, theyargued that the by-product result can be considered as an independent research result. By confirming thatthe by-product measurement would not interfere with the other PAC-approved programs, the Committee
approved the modification to maximize the output from RIBF within the limited BT. This result of thediscussion was reported to the RNC director who also approved it. The UEC chair requested that theCommittee give due consideration to fairness to all other programs when these issues are raised (Suda).
Note that the by-product measurement will be reported to the NP-PAC at a later date by the director.
3. Next meetings
The next meeting, the first one in FY2012, will be held on Friday, April 20, 2012, at 13:30



In principle, the meetings in the next fiscal year starting from April will be held on the third Friday,
at 13:30. As exceptions, it was noted that the meeting will not be held in August and that the meetingin October will be held on the second Friday (12th).