Minutes of the 45th Machine-Time Committee Meeting
Date and time: June 10, 2011; 10:00–11:50
Place: RIBF Bldg., Room 203
Attendees: Sakai a (Chair), En’yo a, †, Kamigaito a, Kase a, Kubo a, Kubono b, K. Morita a, Motobayashi a, †, Ueno a,Uesaka a, Uwamino a, Wakasugi aAbsent: Abe a, Fukunishi a, Haba a, †, Sakurai a, Shimoura b, Teranishic, †, Yoshida a, †a

RNC / b CNS / c RIBF-UEC / † Observer(in random order)

Reports1.

Beam-time schedule changes (Sakai)In response to a request from the representative and CNS director and given the significance forphysics of the experiment, the MT Committee chair has added, with the agreement of the relevant
departments within RIKEN, 1 extra day to the beam time (BT) of NP1012-SHARAQ05-01 (Yako etal., SHARAQ, Jun/5/9:00 – Jun/11/9:00).

The other BTs were conducted as scheduled from May 20.

Relevant to this report, rules on the extension and addition to BTs were discussed. This issue will be
discussed again in the next meeting.

2.

Status of RIBF operationPerformance check of BigRIPS / ZDS / SHARAQ (Kubo)–

The performance of BigRIPS / ZDS was checked by transporting primary and secondary beams
to the end of BigRIPS / ZDS, where several Bρ settings were examined.

–According to the on-line analysis, no significant problem due to the East Japan Earthquake wasfound in the production, isotope-separation, and particle-identification of RI beams, indicating
the integrity of the device. Likewise, no problem was found with the beam-line counters,
although an unexpected shift was observed with a PPAC detector in the vertical direction (Theorigin of the shift will be investigated later).

–The magnification measured at each focal plane was in good agreement with the calculatedvalue. However, discontinuity of the beam profile between F7 and F8 was reproduced in thevertical direction.

–The device integrity was also confirmed for the dispersion-matching beam line with respect tothe SHARAQ Spectrometer.

Repair of the RIBF facility–

The RIPS beam-swinger system was damaged by the earthquake. Since a duct inside the system
is also used as a beam transport line to RIPS, experiments cannot be carried out with RIPS even
if the beam swinger is not necessary. It will be repaired this summer. (Kase)–3.

A layer short was found in the RRC coil. It will be repaired this summer. (Kamigaito)

Status of the PAC meetings (Ueno)

9th NP-PAC: The reports on i) in-house technical reviews and ii) follow-up evaluations of completed
BTs were sent to the PAC. Report i) was also sent to the representatives. The PAC is now conducting apreliminary review. Relevant to this report, total BT approvable in the 9th PAC meeting was discussed.



8th ML-PAC: The PAC meeting will be held sometime at the end of August,early September,

2011.


3rd In-PAC: The PAC meeting will be held after September.

Topics discussed
1. Approval of the minutes of the previous meeting (Sakai)
2. SHE experiment in July–September (Sakai)In view of the need to conserve on electricity use this summer, the possibilities for BT scheduling ofthe SHE experiment were discussed. To find a solution, further discussions will take place with
relevant departments and administration offices

3. FY2011 second half-year BT schedule (Sakai)
The following limitations and constraints to determine the BT schedule for the second half of FY
2011, from Oct. 2011 to Mar. 2012, were discussed.
–

Scheduled power stoppages and maintenance: A power stoppage for the Wako campus isscheduled for Oct, 8–10, and CGS maintenance is scheduled for Jan. 2012 (SRC/BigRIPS
cooling will be stopped during this period of time), and alternate dates for electricity stoppage(Mar. 10–11. 2012).

–

External power usage: The restriction on external power use by the Nishina Center, as decidedby the RIKEN Emergency Headquarters, is a maximum of 10.5 MW from Oct. to Nov., 8.5
MW from Dec. 1 to 11, 5 MW from Dec. 12 to 31, 3.5 MW in Jan. 2012, and 5 MW from Feb.
to Mar. 31, 2012. No BT can be scheduled for Jan. 2012. BTs which need the RIBF cyclotron
cascade acceleration including fRC and IRC can be scheduled between Oct. 11 and Dec. 11.

–

Four educational BTs of the University of Tokyo with the AVF cyclotron will be scheduled inOct.–Nov.

–A new gas-stripper system will be installed at the exit of the RRC sometime in Jan.

–Construction work around and upstream from SAMURAI for three weeks in Feb.

–

Installation of STQ sometime in Feb.

–Improvement work on the fRC scheduled for three weeks in Mar.

The BT outline of the new RIBF facility was discussed taking the above constraints into account.
After the cooling start of SRC/BigRIPS in early September, BT scheduling of 238U from Oct. 11 (i.e.,
after the electricity stoppage) to Nov. and 124Xe in early Dec. are currently under consideration.
After the CGS maintenance in Jan., the SRC/BigRIPS cooling will be recovered by the middle ofFeb. In terms of external electric power, BTs in the mode of AVF-RRC-SRC can be scheduled forthe middle to the end of Feb. In March, a BT series of 18O beams in the same acceleration mode
will be scheduled for SAMURAI commissioning and others.



The outline of the second half-year BT schedule will be discussed further and decided in the next
MT Committee meeting.

4. Other issues
Partitioning of BigRIPS and ZDS areas into two different radiation controlled areas. (Kubo /Uwamino)

The partitioning work will be carried out July–September, but the modification of the radiation
control system will be delayed until December.

5. Next meetingThe next MT Committee meeting will be held on Friday, July 15, 2011, at 13:30.

The meeting after the next will be held on Thursday, September 22, 2011, at 13:30.