HRIBF Information for Proposals - PAC-6

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 are found in our 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.

Neutron-rich RIB Development - Isobarically pure Br and I beams

We presently plan to provide isobarically pure beams of Br and I isotopes during the next scheduling period. Purity is achieved by chemically separating these isotopes using surface ionization (LaB₆) and directly producing negatively charged ions. Expected intensities may be found in a table on our website.

Beam contamination continuously sampled via X-ray detection

We have recently utilized X-rays to sample the isotopic components of a neutron-rich beam of mass 128 at approximately 2.3 MeV/nucleon. Data determining the amount of Sn, Sb, and Te isotopes and a sketch of the set-up is provided on our website. This technique for monitoring changes in the beam components should be fairly universal for accelerated beams. Detection efficiency is limited so this technique is not possible on an event-by-event basis.

Batch-mode source

As outlined in the Winter 2001 newsletter problems arose with the production of ⁵⁶Ni beams using the batch-mode source which is designed for long-lived species. These problems are not resolved and we do not encourage at this time proposals requiring this beam. The source did perform as expected with ¹⁸F; however, the KENIS has better yield for this beam.

Silicon strip detector array for HyBall

A 288-channel silicon strip detector array is presently being constructed and will undergo commissioning tests during the next scheduling period. Compatible with the present CsI detector array (without the forward two rings of detectors; 7-29 degrees in the lab), this system may be used in dE-E telescope configuration with 150 and 400 micron thick detectors. At present, we do not think it suitable to accept additional experiments (e.g. transfer experiments) until this device is ready.

Windowless gas target system

The windowless gas target system has undergone offline tests and has attained a thickness of 5x10¹⁸ He atoms. Tests and ES&H reviews will need to be completed before hydrogen gas may be used and the system available for outside users. It is not anticipated that we will accept experiments requiring this system.

DRS commissioning

The DRS will undergo further commissioning tests during this period to improve the overall system transmission and to test new configurations of the target station (including the windowless gas target system) and focal plane components.

Microchannel plate plus foil detectors

We are in the process of acquiring more microchannel plate (MCP) detectors for use as beam counters (suitable up to 1-4 MHz) and position sensitive focal plane detectors. In some cases, these detectors are built with removable foils so that they do not adversely impact beam quality when not needed.

Silicon "telescope" for decay experiments

A large area silicon detector has been added behind the double-sided silicon strip detector for charged particle radioactivity experiments. This detector has been incorporated into the digital processing data acquistion system and is typically used to detect beta and beta-delayed proton events.