Ion Sources and Accelerators at the Fox Laboratory
SNICS Source
The SNICS (Source of Negative Ions by Cesium Sputtering) is one of the beam sources used at Fox Lab, namely those coming from solid chemicals. It creates a negatively charged beam by accelerating vaporized cesium metal to strike a cathode, "sputtering" particles that form the beam in the process.
RF Source
The RF-Discharge Source is one of the sources used at Fox Lab, mainly for beams generated from gaseous materials like 3He and 4He. The beam is created by the acceleration and focusing of helium ions towards the stripper foil inside the TANDEM.
9-MV FN Tandem Accelerator
The John D. Fox laboratory operates a two-stage accelerator comprised of a 9-MV Super-FN Tandem van-de-Graaff accelerator and an 8-MV superconducting linear accelerator (LINAC). The Super-FN Tandem is injected by either a NEC SNICS-II cesium sputter ion source, for most beams created from solid chemicals, or an NEC RF-discharge source for beams generated from gaseous materials, most importantly 3He and 4He. Among the beams available from the sputter source is the radioactive isotope 14C. A negative beam enters the Tandem on the low-energy (LE) end, and is accelerated towards the high-energy (HE) end by a voltage potential generated by the van-de-Graff generator consisting of two rotating chains. At the midpoint of the Tandem, the negative beam strikes a stripper foil which "strips" it of electrons, causing the beam to become positive and carry on into the rest of the lab.
Superconducting LINAC
The beams from the Tandem are injected into the LINAC, which more than doubles their energy. The Superconducting Linear Accelerator consists of twelve accelerating resonators installed in three cryostats, plus buncher and re-buncher each located in their own cryostats. The resonators are niobium-on-copper "split-ring" resonators produced by Argonne National Laboratory. The cryostats were designed and built at FSU. All accelerating resonators are designed for β=0.1.
Beam List
This beam list is not complete but shows examples of beams available from both the Tandem and LINAC. For rare-isotope beams from the RESOLUT facility see "DEVICES → RESOLUT". Energy boost provided by the LINAC is only available in target room 2 (TR-2).
| Beam | Source | Maximum Tandem Energy [MeV/u] | Maximum LINAC Energy [MeV/u] |
|---|---|---|---|
| 2H | SNICS | 8.7 | 8.7 |
| 3He | RF | 8.7 | 12.2 |
| 6Li | SNICS/RF | 5.8 | 9.1 |
| 16O | SNICS/RF | 3.8 | 7.8 |
| 24Mg | SNICS | 2.9 | 6.4 |
| 32S | SNICS | 2.4 | 5.6 |
| 40Ca | SNICS | 2.2 | 4.7 |