Many of the experiments performed at the 9 MV Tandem of the "Horia Hulubei" National Institute of Physics and Nuclear Engineering (IFIN-HH) in the last years were focused on the measurement of lifetimes of nuclear states. A wide range of such lifetimes was covered, from tens of femtoseconds by using the Doppler Shift Attenuation Method, to picoseconds using the RDDS method and to nanosecond range using the newly developed in-beam fast-timing method. The setup used in these experiments was in continuous improvement by increasing the number of detectors, using various detector types and changing their geometry. By consequence, a new array was needed, with a stable geometrical setup and an improved flexibility.
Recently a multidetector setup dedicated to γ-ray spectroscopy studies was built and installed. ROSPHERE (ROmanian array for SPectroscopy in HEavy ion REactions) is composed by a total of maximum 25 detectors of two types: Compton suppressed HPGe detectors and fast LaBr3(Ce) scintillator detectors. It is a powerful instrument for lifetime measurements using the in-beam Fast Electronic Scintillation Timing (FEST) method or, together with a state of the art plunger device, using the Recoil Distance Doppler Shift (RDDS) method. If the experiment requires high resolution and high efficiency, ROSPHERE can be operated as a full HPGe array.
The experimental set-up working on the zero-degree beam-line of the 9MV Tandem Accelerator at IFIN-HH now offers a high accuracy and repeatability of the heavy ions nuclear physics experiments. This is achieved by an automated moving system, placed inside a circular reaction chamber, consisting of four moving arms covering a complete 360 degrees. Each arm can hold one detector and is powered by a stepper motor having the possibility of micro-stepping up to 1/256 if the application requires, with a reduction gear box of 60:1 and a resolver acting as a witness for eventual position corrections. Moreover, the target support, positioned in the center of the chamber, is also assisted by a stepper motor and can rotate over 360 degrees clockwise or counter clockwise. Two identical Delta E - E telescopes have received an upgrade in both the gas automated pressure and constant flow regulation by using a software implemented PID (Proportional-Integral-Derivative) controller.
Five other beamlines are available at the 9MV Tandem Accelerator offering possibilities for the installation of ad-hoc experimental setups performing various types of measurements.
The laboratory was developed to support the nuclear physics experiments performed mainly at the IFIN-HH 9 MV Tandem Accelerator or at other international research facilities in the frame of scientific collaborations (CERN, IN2P3, TUM, IKP, JINR, etc).
The laboratory provides thin films of various thicknesses from several tens of μg/cm2 to several hundreds of mg/cm2 made from both naturally occurring materials and stable enriched isotopes. Such thin films (called “targets”) are dedicated for different types of nuclear structure experiments: nuclear structure and lifetimes measurements of excited nuclear states using γ-ray spectroscopy techniques (Doppler shift attenuation, plunger, and fast-timing), nuclear structure studies using the activation technique, cross-section measurements of interest for nuclear astrophysical processes, etc.
To assure good target quality the laboratory includes state-of-the-art equipment used for thin-film fabrication technology and consist of Physical Vapor Deposition (PVD) and mechanical rolling techniques.
We invite you to submit your experiment proposals for the 2023 full year campaign at the Bucharest Tandem/Tandetron accelerator complex (9 MV, 3 MV, 1 MV). Your proposals, following the template provided (https://useroffice.nipne.ro/PAC/IFIN-HH_Proposal_Template.docx), should be submitted no later than the 28th of October 2022, via the new user office website:
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