Test bench to commission a third ion source beam line and a newly designed extraction system

Abstract

The HIT (Heidelberg Ion Beam Therapy Center) is the first hospital-based treatment facility in Europe where patients can be irradiated with protons and carbon ions. Since the commissioning starting in 2006 two 14.5 GHz electron cyclotron resonance ion sources are routinely used to produce a variety of ion beams from protons up to oxygen. In the future a helium beam for regular patient treatment is requested, therefore a third ion source (Supernanogan source from PANTECHNIK S.A.) will be integrated. This third ECR source with a newly designed extraction system and a spectrometer line is installed at a test bench at HIT to commission and validate this section. Measurements with different extraction system setups will be presented to show the improvement of beam quality for helium, proton, and carbon beams. An outlook to the possible integration scheme of the new ion source into the production facility will be discussed.

Can particle beam therapy be improved using helium ions? – a planning study focusing on pediatric patients

“…Due to medical arguments and the reduced lateral straggling in matter 4 He seems to be the better choice over 3 He. For the use of 4 He in a clinical setting a retuning of the beam line and bending magnets as well as a new ion source are required [11]. Gantries designed for carbon ions can be adapted for 4 He.…”

“…Especially for pediatric patients 4 He could have the potential to reduce the volume of irradiated normal tissue, without bringing the disadvantage of additional dose caused by the fragmentation tail, like it is observed for carbon ions [11]. This could not only improve the dose distribution for small tumor lesions, but also reduce the total overall dose for children suffering from large tumors, potentially reducing side effects and secondary cancer induction [12][13][14][15].…”

Roadmap: helium ion therapy

“…But as a result of HIT's risk management a technical solution was required that safely identifies and solely accelerates 4 He 2+ . As a potential ion mixture in the ion source plasma chamber having a mass-to-charge ratio A/Q=2 ( 12 C 6+ , 14 N 7+ , 16 O 8+ , 20 Ne 10+ ) could be the result of a leakage, at HIT the residual gas is permanently monitored using a mass spectrometer coupled to the accelerator interlock system (Winkelmann et al 2012a(Winkelmann et al , 2012b. The first phase of the permanent establishment of a new ion species is the physical and radiobiological characterization of the beam to provide the information for the base data generation and the definition of the pencil beam library shared by the accelerator controls and the treatment planning and modelling platforms (Mairani et al 2016a, Pantechnik 2021).…”

“…A quasi-parallel operation of all ion sources with very short changeover times optimally supports the commissioning of the new ion species. The technical challenge consists in finding a solution for a compact low energy transport line equipped with two ECR ion sources that can be switched within minutes (Winkelmann et al 2012a(Winkelmann et al , 2012b.…”

“…This analyzing magnet serves two purposes: it is used to select between the carbon and the helium ion source and it allows for the selection of the appropriate ion species to be transported into the first linear accelerator section, the RFQ (see figure 3). The original three-electrode design of the ECR ion source was upgraded to a four-electrode set-up resulting in an increased beam brilliance (Winkelmann et al 2012a(Winkelmann et al , 2012b .…”