Minutes of the 50th Machine-Time Committee Meeting
Date and time: December 16, 2011; 13:30–14:35
Place: RIBF Bldg., Room 203
Attendees: Sakai a (Chair), En’yo a, †, Fukunishi a, Haba a, †, Hayashi a (in lieu of Abe), Inabe a (in lieu of Kubo),
Kamigaito a, Kase a, Kubono b, Nishimura a, †, Otsu a (in lieu of Sakurai), Shimoura b, Suda c, †, ‡,Ueno a, Uesaka a, Uwamino a, Wakasugi aAbsent: Abe a, Kubo a, Morita a, Motobayashi a, †, Sakurai a, Yoshida a, †abc†RNC / CNS / RIBF-UEC / Observer / ‡ TV Attendee(in random order)

Reports
1.

Change of the beam time schedule (Ueno)
It was approved by the RIKEN Headquarters that i) the operation of SRC-BigRIPS using the utility
power of 8.5 MW has been extended from 9:00, December 12 to 9:00, December 19, and ii) the operationof RILAC-GARIS using the utility power 5.5 MW has been newly scheduled for January when the CGS
system will be stopped. In response to these decisions, the beam-time (BT) schedule from December toJanuary has been changed as follows:
Experimental-Program-Number
SRC

previouschanged

NP0702-RIBF30-04 (Yoneda)
NP0702-RIBF31-04 (Aoi)
NP1012-RIBF63-01 (Sumikama)MS11-03 (Kubo)
NP0702-RIBF09-01 (Lewitowicz)

Nov/09/09:00 – Nov/16/21:00
Nov/17/21:00 – Nov/26/09:00
Nov/27/09:00 – Nov/29/09:00
Dec/05/09:00 – Dec/11/09:00
Dec/11/09:00 – Dec/12/09:00→→→→→

Nov/09/09:00 – Dec/03/21:00
Dec/05/09:00 – Dec/08/09:00
cancelDec/12/09:00 – Dec/18/09:00
Dec/18/09:00 – Dec/19/09:00

Nov/03/09:00 – Dec/01/ 9:00
Dec/23/09:00 – Dec/29/9:00
N/A→→

Nov/03/09:00 – Dec/19/09:00
cancelJan/15/09:00 – Jan/29/09:00

conditional
conditional
Dec/18/9:00 – Dec/19/21:00→→→

Dec/20/09:00 – Dec/21/09:00
Dec/22/09:00 – Dec/24/09:00
Dec/26/09:00 – Dec/27/09:00

Dec/13/09:00 – Dec/20/09:00
Dec/20/21:00 – Dec/22/09:00
Dec/25/09:00 – Dec/29/09:00→→→

Dec/20/9:00 – Dec/27/09:00
Dec/28/9:00 – Dec/29/21:00
cancelRILAC stand-alone
NP0702-LINAC12-13 (Morita)
ML1006-LINAC27-02 (Haba)
NP0702-LINAC12-15 (Morita)
AVF stand-alone
MS11-14 (Sakamoto)
RI0702-AVF04-29 (Haba)
ML1101-AVF32-01 (Yokoyama)
RRC
NP0811-RRC65-03 (Georgiev)
NP0702-RRC01-27 (Wada)
NP0709-RRC39-03 (Nagatomo)

2.

RIBF operation (Fukunishi)
238

U beam delivery

Following the recovery from the SRC trouble, a238U beam was delivered to the BT of
NP0702-RIBF30-04 (Yoneda) at the maximum current Imax ~ 3.5–4 pnA (Iave ~ 2.5 pnA on average)

The beam delivery was, however, delayed not only due to the recovery process of SRC but also theaccelerator conditioning required for the beam delivery.
124

Xe beam delivery

The beam transportation to BigRIPS was completed in the morning of December 12. As ofDecember 16, 83 % of the requested BT is being supplied by the beam delivered at Imax ~ 13.5 pnA(Iave ~ 8 pnA). Compared with 238U, the 124Xe beam was delivered smoothly. However, beam tuningmust be continued due to large fluctuations in the current. Moreover, the charge-stripper foil should
be changed often due to short endurance time. It was mentioned that in the current 124Xe beam series,
a fixed-type foil has been used as the first-stage stripper at the RRC-A02 site.
3.

Status of the Machine Study (Inabe)
The BT of MS11-03 (Kubo), a BT in the Machine Study category for proton-rich RI beam deliveries,
started in the morning of December 12 since a 124Xe beam was transported to BigRIPS The measurementof production cross sections and purity for a 100Sn secondary beam is ongoing. In addition to thesemeasurements, the momentum distribution will be conducted for isotones and isotopes around 100Sn.

4.

Status of the PAC meetings (Ueno)

10th NP-PAC: The meeting was held on December 9-10, 2011 as scheduled. A PAC report will besent to both RNC & CNS directors soon.

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

Topics discussed
1. Approval of the minutes of the previous meeting (Sakai)
2. FY2012 first half-year BT schedule (Sakai)
The outline of the BT schedule for FY2012 was discussed together with the construction plans andstatus/plan of beam developments which may affect the schedule. A BT plan of the RNC enterprise which
will use AVF and RRC was also discussed. After deliberation, it was approved that the BigRIPS-related
experiments using 48Ca and 124Xe primary beams (and 70Zn, if possible) are scheduled in the first half yearof FY2012 following the 18O beam series that will start from March. The call for BT scheduling requests
will be announced in January.
3. New MT Committee member (Sakai)
The EURICA (Euroball RIKEN Cluster Array) project will unfold over the period of year and half
starting from April, 2012. In connection with the project, Nishimura, the EURICA Project Manager andSenior Research Scientist of the RNC Radioactive Isotope Physics Laboratory, was appointed by the MT
Committee Chair Sakai as a new regular observer from January, as provided in the Article 5 of RIBF MT
Committee Bylaws. Yamaguchi, the contact person of CRIB and Lecturer at CNS, the University ofTokyo, was also appointed as a new regular observer from January.
4. Next meetings
The next MT Committee meeting will be held on Friday, January 20, 2011, at 13:30.