Information for HRIBF PAC-10 Proposals

mass difference calculator	Estimate isobar contamination
TOPS	Estimate tandem voltage and beam charge state(s)
Neutron-rich beam yields	Estimate yields based on TOPS results

We encourage you to contact us with suggestions for the beams you require to pursue your physics research. Parameters as to what constitutes a suitable beam for the HRIBF may be found in our more recent newsletters.

We ask that you need to be aware that scheduling experiments at our facility is difficult. In some cases such as transfer experiments, suitable equipment is not yet in place to take full advantage of the allocated beam time. In other cases, sufficiently many experiments must be available before it is "cost effective" to schedule a particular RIB ion source or endstation configuration.

Additional information reflecting the present status of equipment and techniques is provided below in information from previous PACs or may be found from our recent newsletters. Older articles on major experimental endstations and neutron-rich experiments may also be useful.

Information from previous PACs

PAC-9 (comprehensive update)
PAC-8
PAC-7
PAC-6e
PAC-6

Request for Letters of Intent: ⁶⁸Ge and ^25,26Al

We are requesting letters of intent be submitted for beams of ⁶⁸Ge which has a halflife of 270.8 days. A sputter ion source (as with ⁷Be) can be used for this isotope which can be purchased commercially. Some material preparation will be necessary prior to insertion into the source but we believe this is manageable. The anticipated accelerated beam intensity on target is on the order of low-10⁷ i/s.

Beams of ²⁵Al (7.18 s halflife) and the metastable state of ²⁶Al (6.4 s halflife) should be possible at accelerated beam intensities on target of low-10⁴ i/s. Note that due to the long halflife of 7.2 x 10⁵ y, we do not know what the ground state component of the A=26 beam will be. Development work on this beam has been carried out with tandem beams and extracting AlF+ ions. Since these molecules have also been used to transport our Fluorine beams, we are confident we know how to handle these beams. Things yet to do are high-current tests with ORIC and to try new target material which has a higher density of Si. The above intensity assumes the already-tested material and 5 uA of ORIC beam.

Neutron-rich RIB Development - An update

ORIC is now able to deliver 54 MeV proton beams to the uranium carbide targets. This increase in energy is expected to increase yields in all neutron-rich species by at least a factor of 50%. Recently, 6 uA of ORIC beam at 54 MeV has been shown to have the same yield for selected isotopes as 10 uA of 42 MeV beam. For more information contact Carl Gross at liaison@phy.ornl.gov.

Proton-rich RIB Development - An update

Other proton-rich beams are in various stages of development. We anticipate being able to deliver approximately 1x10³ i/s/uA on target of ²⁷Si, and 4x10³ i/s/uA on target of ³⁴Cl. It should be noted that these beams have not been accelerated through the tandem and we are assuming 10% transmission to the target. We do not know how many microamps these targets can withstand. More development work is planned. The Cl work has been done with natural abundance of ³⁴S (4.2%) in the target. Higher yields are possible if enriched material can be used to form CeS targets. For more information contact Dan Stracener at stracener@phy.ornl.gov.

Small CsI detector array

Elements of the 5-ring CsI array have been tested at the RMS target area. This detector is used without absorbers for improved response with heavy nuclei. The entire array should be operational before the PAC-10 deadline for proposals. For more information contact Alfredo Galindo-Uribarri at uribarri@phy.ornl.gov.

Neutron detector array

A 19-element neutron detector array has been installed and tested with beam at the target of the RMS. We estimate that the array will have an efficiency between 11% to 18% depending on the reaction. When used with the RMS, the central detector must be removed. For more information contact Chang-Hong Yu at chy@phy.ornl.gov.

Microchannel plates at final focus of the RMS

The large MCP detector has worked well in several experiments. An additional smaller MCP has been used with the larger one during proton emission measurements. For more information contact Carl Gross at cgross@phy.ornl.gov.

Data acquisition

We have moved to LINUX machines for our data acquisition computers. These replace DEC Alpha machines. In the new system, data is written directly to disk on a new 2-terabyte server. For transport to the user's home, we offer DVD writers (-R,-RW formats) which hold roughly 4.3 GB of data or the usual Exabyte tapedrives. Users are expected to bring their own DVDs and tapes. Tapes will be slowly phased out. For more information contact Robert Varner at varner@phy.ornl.gov.

Recoil mass spectrometer and online test facility

No beams will be delivered to the RMS and OLTF during the period of June through September 2004. The new construction for the High Power Target Laboratory will prevent the delivery of beams to these endstations. During this period we plan on running ^17,18F and ⁷Be to the other experimental areas. For more information contact Carl Gross at cgross@phy.ornl.gov.