Experimental Set-Up & Equipment

The CASPAR underground laboratory is a low-energy accelerator laboratory primarily focused on the study of reactions important for elemental production in stellar environments. The driver of this research is the 1 MV JN model Van de Graaff accelerator, previously operational at the Nuclear Science Lab at Notre Dame. This is the 4th incarnation of the JN over its near 60-year lifetime, a detailed account of which can be found here "The Four Lives of a Nuclear Accelerator"

Begining from the 1 MV JN accelerator, the CASPAR system is ~ 16 meters long, with a 25 degree deflection for momentum selection at the midpoint and a modular target station equipped for either gas or solid-target experiments. Positive ions are created in the terminal of the accelerator via a gas-fed RF ion source, equipped to produce both proton and alpha beams. All ion optic elements on the beamline (quadrupoles, steerers etc) are magnetic and external to the beamline.

Overview Specifications

Component	Description
JN Accelerator	Electrostatic accelerator, voltage range 150 kV-1.1 MV
RF Ion Source	Proton Beam ~250 μA, Alpha Beam ~220 μA
Analyzing Magnet	25-degree dipole, 0-degree and "mass 2" lines
Target Stations	Extended, recirculating, windowless gas target
	0-degree and 55-degree solid target system
Vacuum System	Turbomolecular pumping, conflat system beamlines