Proposals to be submitted to the
Program Advisory Committee
should be received on or before 9 am EST Monday, June 15, 2009.
Detailed instructions including important dates may be found on our
website. A list of
including expected intensities is also available.
Some web-based programs may also be beneficial to your planning:
We encourage you to contact us with
suggestions for the beams you require to pursue your physics research.
as to what constitutes a suitable beam for the HRIBF
may be found in our more recent newsletters.
We ask that you be aware that scheduling experiments at our facility is
not straightforward; several experiments must be available before there is
"critical mass" so that 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 on our
equipment web pages. You are encouraged to
contact the mentor of the equipment should you have any questions.
Information from previous PACs is provided below.
The second RIB production platform will be operational at the end of FY09.
All ion sources presently in use at HRIBF will be available at this time.
With two operational platforms, transitions between different ion sources
can be made quickly resulting in less down-time for ORIC.
In addition, RIB delivery can continue during the cool-down and change
out of a spent ion source.
The platform of IRIS-2 is much larger, better shielded, and more flexible
than IRIS-1. Laser ion sources are being developed for implementation at
IRIS-2 but will be incompatible with IRIS-1 due to its small size and
location in the building. We anticipate that the first beams utilizing
laser techniques (ionization or photodissociation) will be available
- LeRIBSS - Low energy Radioactive Ion Beam Sepctroscopy Station
is commissioned and has been used for experiments. Although more
experience is necessary, quality data has been obtained using positive
ions of 79-81Zn and negative ions of 75,77Cu.
In the 81Zn experiment, essentially pure activity samples were
obtained even though the intensity of the neighboring 81Ga
is estimated to
be a factor of 105 larger. We estimate that the resulting Zn
activity was half the total rate. Note that the performance of the isobar
separator should be better for positive ions as they do not have to pass
through the charge exchange cell when we use the electron beam plasma
target ion source. In addition, while positive ions can be expected to
have higher yields, there are many more contaminants in the beam
often from molecular beams.
The ability to pulse the beam using an electrostatic steerer for measuring
the grow-in and decay of the collected activity will be
added to the next experiments. We expect pulsing will be possible
down to the few millisecond level.
We also expect the small Micro-channel plate (MCP) to become operational
this period. With a very thin carbon foil, this MCP is positioned just
before the implantation point of the moving tape. The 200-keV ions will
pass through the foil and be implanted into the tape. Electrons emitted
from the carbon foil will be detected by the MCP and allow fast time
correlations between implantation and decay events. This time correlation
technique is expected to enhance detection of nuclei very far from
stability, ie., low intensity beams of ions with very short halflives.
- 3Hen β-delayed neutron detector
We expect this
ionization counter array for neutrons
to be completed
this fiscal year and should be available at
ranging-out experiments in
2010. Each ion
chamber 2 foot long and either 1 or 2-inch diameter with a center wire
electrode. The 74 stainless-steel tubes filled with 10 atms of 3He
gas are held in concentric rings in a high-density polyethylene (HDPE)
holder about the beam pipe. These ionization counters detect the neutrons
via the 3He(n,p)t resonance reaction. Although these detectors are
poor in fast timing applications, they are highly efficient. Our simulations
suggest we can expect 75% efficieny for 0.001-1.5 MeV neutrons and 50%
efficiency for 5 MeV neutrons.
- Electronics upgrade for CHARMS
The old analog electronics for
neutron array and the
detectors located at RMS focal plane will be replaced with GRETINA
digital signal processing modules. Each module contains 10 channels which
digitize the preamp signals at 100 MHz with 14-bit resolution. Thirty
modules have been purchased which offer 300 channels for detectors. It is
envisioned that our 11 Clover Ge detectors will each require a single module,
HyBall will use 10 modules, and the neutron array will use 2 modules.
The two focal plane detectors require two additional modules.
The remaining 5 modules can be used for additional detectors such as
the zero-degree Bragg detector for RIB sampling and monitoring.
We expect this system to be operational in late summer 2009.
- Our new beam line (BL-36)
We have begun to purchase equipment for a new beam line positioned
next to the Enge spectrometer. Designated as BL-36, we envision
the beam line to host
ORRUBA charged particle
detector array and the rejuvenated
The electronics for the Spin Spectrometer will be the same GRETINA modules
described above. We will attempt to configure both arrays to function
together which should provide a power system for the study of (d,pγ)
in inverse kinematics with RIBs.
The beam line is partially funded by the Center of Excellence for
Radioactive Ion Beam Studies for Stewardship Science