PROGRAMME FOR THE PROMOTION OF THE EXCHANGE AND SCIENTIFIC COOPERATION BETWEEN GREECE AND GERMANY
PROGRAMME FOR THE PROMOTION OF THE EXCHANGE AND SCIENTIFIC COOPERATION BETWEEN GREECE AND GERMANY
Upgrading the Atomic Physics experimental setup at the 5.5 MV tandem Van de Graaff accelerator of the NCSR “Demokritos” by developing coincidence techniques
Progress of the project
The new ion-TOF spectrometer
After discussions between the team members, the accelerator personel, the accelerator upgrade schedule and the ongoing experiments, it was decided not to follow the initial idea of replacing of the existing gas cell manifold with an exisitng large chamber, hosting all the target components. Instead, a more compact ion time-of-flight (TOF) was proposed to be installed in the beam line as an add-on device to the existing ZAPS setup.
The TOF spectrometer housing chamber was first designed in CAD and then assembled in "Demokritos" from existing parts.
The ion MCP detector was also assempled and is in place.
An undergraduate student has been assinged to study the optical properties of the TOF spectrometer in SIMION ion optics package. See the bachelor thesis of Mr Stogiannis in this site.
Discussions with the German team about the contstraction of the jet and its assenbly to the TOF spectrometer are ongoing.
CAD designs of the TOF spectrometer
The TOF spectrometer assempled in the laboratory of "Demokritos"
The ion MCP detector
The projectile charge state magnetic selection
We have performed relativistic calculations for the ion trajectories through an homogeneous magnetic field. All the necessary parameters (realistic magnetic fields, electromagnet dimensions, existing wiring, current supplies, etc.) have been taken into account and the appropriate geometry has been decided.
The upgrading of the ZAPS setup as to include the projectile charge state magnetic selection was desinged according to the space limitations of the L-45 beamline.
An electromagnet, property of "Demokritos", was incorporated in the extention of the ZAPS setup. A suppoting table for the magnet was built in the machine shop of the Tandem laboratory and are in place.
A vacuum tube of 1m length and 200 mm diameter that will host the Faraday cup and the channetron for the ions dtection was bought and is in the lab.
Flanges and tubes were modified accordingly (cutting, welding, etc.) with the help of the machine shop of "Demokritos" used for the beamline connections and the detectors assembly.
Initiation of the extention of the ZAPS beamline to include the magnetic charge separator and ion-TOF parts.
The coincidences hardware
The option to use the existing data acquisition hardware and software has been throughly investigated. After contacting the hardware developer (ATOMKI insitute, Hungary) , we concluded that the existing hardware can be used for electron-ion and ion-ion coincidences after some minor modification. The modifications will take place during the upgrade of the accelerator so that ongoing experiments run smoothly.
The hardware of the data acquisition was sent to the electronic shop of ATOMIKI institute in Hungury and the appropriate modifications were done. The upgraded data acquisition is back in "demokritos" and in place. Its non-coincident operation was tested and found to run smoothly. The coincident operation will be tested in experiments after the upgradinfg of the accelerator.
A channeltron was bought for the needs of the ion detection.