INVAP has designed and constructed a Quadrupole-Dipole-Dipole (QDD) Magnetic Spectrometer and its associated detector for the 20 UD tandem accelerator of the TANDAR laboratory at the Argentine National Atomic Energy Commission (CNEA) in Buenos Aires, Argentina. Built in the late seventies, the 80 million dollar TANDAR is still the largest linear particle accelerator in all of the southern hemisphere.

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The vertical structure towering over the Centro Atómico Constituyentes of CNEA is the TANDAR heavy particle accelerator. INVAP designed and built the magnetic optics package of this major piece of research equipment, a QDD magnetic spectrometer and its associated detector

The main features of the system are a large acceptance angle, a large range of linear momenta and high resolution of the detector in both position and incidence angle. The instrument is used for heavy ion detection to support research activities on low energy nuclear reactions and on accelerator mass spectrometry (AMS).

INVAP has been in charge of all the stages of this project, right from the conceptual design on through the commissioning of the whole system. Relevant equipment as the entire magnetic optics system, plus coils, target chamber, particle detectors and data acquisition system were designed and manufactured in Argentina by INVAP. The use of commercially available products was restricted to some small components like pumps, valves, processors, etc. TANDAR is a very hand-crafted piece of hardware indeed!

Included in this project were also all the auxiliary systems, including the high vacuum system, and the magnet coil cooling system. INVAP also designed and built the target chamber, which admits both the exchange and the extraction of several targets at the same time and under high-vaccum conditions.

The design of the detector for the spectrometer at the TANDAR laboratory was an in-house adaptation of the multiwire detector concept. INVAP designed and constructed all the required hardware for particle detection as well as all the electronics needed to process the generated data.
A detailed description of the system and its performance has been reported in the paper: "Initial tests of the magnetic spectrometer at the TANDAR accelerator" by E. Achterberg et al, Nuclear Instruments and Methods in Physics Research A 361 (1995) 222-228.