The front entrance of the ex-MRI superconducting magnet
reconverted for blue sky nuclear physics research
The ISS is an experimental setup for precision nuclear structure studies using inelastic scattering and transfer reactions induced by radioactive ion beams.
The system comprises a set of movable silicon position-sensitive detectors and a target-changing mechanism, cleverly positioned along the beam axis inside a superconducting solenoid magnet.
Under the presence of the magnetic field, the light-charged particles (protons, deuterons, tritons, alphas) emitted in the nucleon transfer reactions are directed into a silicon position-sensitive array.
The latter provides a precise measurement of the distance detection position-to-target and the energy of the light ions.
This collected information, together with the known parameters of the reactions (incoming beam energy, magnetic field intensity, target thickness, etc.), allows physicists to reconstruct the angular distribution of these light-emitted ions, which then reveals characteristics of the nuclear structure of the incoming ions.
The
detector bed and support,
target-changing mechanism and the primary silicon position sensitive detector designed and assembled at STFC Daresbury Laboratory before to shipping to CERN. Three sides
of the hexagonal-shaped primary detector are visible at the top centre of the left picture.
Four groups from the Technology Department at Daresbury Laboratory were involved in this project. They include:
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Projects and Mechanical Engineering - design, construction, and assembly test of the silicon array and target changing mechanism.
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Mechanical, Metrology, and Technical Engineering
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Electrical Engineering- installation and test of the motorisation control system.
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Nuclear Physics - experiment design simulations, assembly and vacuum tests, magnet safety and operation at CERN, electronics and data acquisition system, and commissioning, plus exploitation.
The geometry of the target holder, detector bed and support of the primary detector, defined in a GEANT4 simulation. Four transfer reaction events have been simulated. The tracks of the light particles emitted in a backward direction related to the beam are displayed in blue.
An animation showing simulated light-charged particles event by event.
Since the ISS was commissioned in 2018, the Isolde and Neutron Time-of-Flight Experiments Committee has approved 25 experiments:
- 13 experiments have been completed.
- 2 experiments are scheduled.
- 10 experiments are waiting to be scheduled.
Further information
Learn more about the ISS:
Written by Marc Labiche, Nuclear Physics group leader.
