Minutes of the 40th Machine-Time Committee Meeting
Date and time: January 21, 2011; 13:30–14:40
Place: Nishina Bldg., Room 201Attendees: Sakai a (Chair), En’yo a, †, Fukunishi a, Kambara a, †, Kamigaito a, Kase a, Kubo a, Kubono b, Morita a,Sakurai a, Shimoura b, Teranishi c, †, ‡, Ueno a, Uwamino a, Wakasugi a, Tanaka a, †Absent: Abe a, Motobayashi a, †, Yoshida a, †a

RNC / b CNS / c RIBF-UEC / † observer / ‡ TV attendees(in no particular order)

Reports
1. Beam-time schedule changes (Ueno)z

The MS10-10 beam time (BT) (Goto et al. / AVF room / Jan. 17 at 10:00-24:00) was canceled.

z

In response to a request from the CNS director and given the significance for physics of theexperiment, the MT Committee chair has extended the NP0906-AVF04-2 (Chun Sik Lee et al. /CRIB / Jan/9/21:00 - Jan/15/21:00) BT by 0.5 days. (Sakai).

z

The other experiments, all of which are using the former RARF facility, are being carried out asscheduled. The SHE experiment is scheduled to restart on Jan. 22.

2. Status of the PAC meetings (Ueno)zNP-PAC¾

8th NP-PAC: The PAC review report on the newly proposed experiments and the re-evaluationof backlogs were sent to the representatives.

¾

9th NP-PAC: Informal consent to be a PAC member was obtained from eight candidates. The
9th NP-PAC meeting will be held June 24-25, 2011. The scheduling is now being confirmedwith PAC members, including these new candidates.

z

7th ML-PAC¾

The PAC meeting was held Jan. 11-12, 2011 as scheduled. The PAC is now making a report.

Topics discussed
1. Approval of the minutes of the 39th meeting (Sakai)
2. FY2011 first half-year BT allocation (Sakai)zBTs with SRC-accelerated beams¾

Machine studies for the delivery of new beams, 124Xe (Feb.∼Mar. & May), 70Zn (Apr.), Kr(Apr.), 238U (May), and 48Ca (Jun.), will be a central subject.

¾

PAC-approved BTs will be allocated, if they can use RILAC-injected light ions (Apr.), 70Zn(Apr.), 124Xe (May), and AVF-injected light ions (Jun.).

z

Effect of this BT plan on the radiation work being scheduled in this summer for strengthening
BigRIPS against radiations (Tanaka)¾BigRIPS Team plans to install i) a radiation shield at F0-STQ1 and ii) a pillow-seal system at

STQ1-D1 next summer to strengthen BigRIPS against radiations. For a realistic operation time,
the total beam dose must be controlled so that the external radiation rate of the working area
will be lower than 1∼2 mSv/h and 400 μSv/h for cases i) and ii) by next summer (In thefollowing, the stricter conditions required for ii) were discussed).
¾An external radiation rate, 150 μSv/h, was estimated from a total beam dose of theBigRIPS-based experiments in the last autumn−winter period.

¾In the above BT plan, the beam energy and current of 18O (Apr.) is a key for the externalradiation rates. BigRIPS Team empirically estimated it as 18O (1500 pnA*day at E/A = 345
MeV or 495 pnA*day at E/A = 280 MeV) + 70Zn (700) + 124Xe (100) + d(0) + 124Xe(60) +18O(600) = 2960 or 1955 pnA*day. It is impossible to meet the limit of 400 μSv/h, if a 18O beam

is delivered with 1500 pnA*day at E/A = 345 MeV, but possible with 495 pnA*day at E/A =280 MeV.
¾After discussions, the MT Committee chair requested the accelerator group to consider thedelivery of a 18O beam at E/A = 300 MeV.

zz

BT scheduling (Ueno)
Jan 17-29:

Call for BT scheduling requests & detector development BT requests

Mid Feb:

Tentative BT schedule

End Feb:

Submission deadline of Accelerator Use Planning Sheet

Early Mar:In-House Safety Review Committee meeting

Mar 18:

Approval of BT schedule by MT Committee

Other issues¾A Q magnet should be moved from SHARAQ to BigRIPS for 18O BTs in April (Kubo).

¾A new STQ magnet and an STQ switching system between ZD and SAMRAI will be installed
just before the SAMURAI commissioning planned for February 2012.

zThe next MT Committee meeting will be held on Friday, February 25, 2011, from 13:30 to 15:00.