For the development of a promising method for the treatment of malignant tumors - boron neutron capture therapy - the accelerator-based epithermal neutrons source has been proposed and created in the Budker Institute of Nuclear Physics. Argon ions formed during stripping of a beam of negative hydrogen ions to protons are accelerated and, in parallel with the proton beam, are transported along the high-energy path of the facility. Depending on the relative number of argon ions, their effect can be from negligible to significant, requiring their suppression. In this work, the current of argon ions reaching the beam receiver in the horizontal channel of the setup was measured. It was determined that the argon beam current accompanying the proton beam is 2000 times less than the proton beam current. This makes it possible not to apply the proposed methods of its suppression.