• D.E. Donets, E.D. Donets, E. E. Donets, V.V. Salnikov, V. B. Shutov, E. M. Syresin
  JINR, Dubna

Accelerated ¹²C ion beams are effectively used for cancer treatment at various medical centers, in particular to treat patients with radio resistant tumors. On the other hand, positron emission tomography is the most effective way of tumor diagnostics. The intensive ¹¹C ion beam could allow both these advantages to be combined. It could be used both for cancer treatment and for on-line positron emission tomography. Formation of a primary radioactive ¹¹C⁶⁺ ion beam with the intensity of 10¹⁰-10¹¹ pps from the ion source may allow cancer treatment and on-line dose verification. ¹¹C isotope is produced in the nuclear reaction ¹⁴N (p,α)¹¹C using the gas target chamber irradiated by a proton beam. If the nitrogen target chamber contains about 5% of hydrogen, approximately 10¹⁴ methane molecules ¹¹CH₄ can be produced each 20 minutes. The separated radioactive methane can be loaded into an ion source. The methodology and technique of formation of high-intensity radioactive carbon beams were tested in the JINR electron string ion source (ESIS) Krion-2 using usual non radioactive methane. The measured conversion efficiency of methane molecules to carbon ions appeared to be rather high, 15 % for C⁶⁺ ions and 25% for C⁴⁺ ions. The developed technique of pulsed methane loading and the experimentally obtained conversion efficiency permit obtaining primary radioactive ¹¹C⁶⁺ beams at the intensity of 10¹⁰ -10¹¹ pps and performing cancer treatment and online dose verification.

• D. E. Donets, E. D. Donets, E. E. Donets, V.M. Drobin, A.V. Shabunov, Yu. A. Shishov, V.B. Shutov, E.M. Syresin
  JINR, Dubna
• A.E. Dubinov, R.M. Garipov, I.V. Makarov
  VNIIEF, Sarov

The so-called reflex mode of Electron String Ion Source (ESIS) operation has been under intense study, both experimental and theoretical at JINR during the last decade. The idea of using a tubular electron string ion source (TESIS) has been put forward recently to obtain 1- 2 orders of magnitude increase in the ion output as compared with ESIS. The project is aimed at creating TESIS and studying an electron string in the tubular geometry. The new tubular source with a superconducting solenoid up to 5 T should be constructed in 2010. The method of the off-axis TESIS ion extraction will be used to get TESIS beam emittance comparable with ESIS emittance. It is expected that this new TESIS (Krion T1) will meet all rigid conceptual and technological requirements and should provide an ion output approaching 10 mA of Ar¹⁶⁺ ions in the pulse mode and about 10 μA of Ar¹⁶⁺ ions in the average current mode. Analytical, numerical study of the tubular electron strings and the design of the TESIS construction are given in this report. The experiments with quasi tubular electron beams performed on the modified ESIS Krion 2 are also discussed there.