High frequency compact low-energy linear accelerator design

1. A compact radio-frequency quadrupole ‘RFQ’ accelerator for accelerating charged particles, the RFQ accelerator comprising:

a bunching section configured to have a narrow radio-frequency ‘rf’ acceptance such that only a portion of a particle beam incident on the bunching section is captured, and wherein the bunching section bunches the portion of the particle beam;

an accelerating section for accelerating the bunched portion of the particle beam to an output energy; and,

a means for supplying radio-frequency power.

2. The RFQ accelerator of claim 1 , wherein the bunching section is further configured to rapidly increase the synchronous phase of the particle beam incident of the bunching section.

3. The RFQ accelerator of claim 1 , wherein the narrow rf acceptance is caused by the input of the bunching section having a synchronous phase of greater than −50 degrees, preferably greater than −40 degrees, and more preferably −30 degrees.

4. The RFQ accelerator of claim 1 , wherein the bunching section is configured to increase the synchronous phase of the particle beam incident of the bunching section to between −25 and −15 degrees.

5. The RFQ accelerator of claim 1 , further comprising a radial-matching section for transforming a particle beam incident on the matching section with a time-independent focalisation to a particle beam with a time-varying focalisation.

6. The RFQ accelerator of claim 1 , wherein the bunching section is less than 40 cm in length, and preferably between 20 and 30 cm in length.

7. The RFQ accelerator of claim 1 , wherein the means for supplying radio-frequency power comprises a plurality of radio-frequency power sources distributed along the RFQ accelerator.

8. The RFQ accelerator of claim 1 , wherein the means for supplying radio-frequency power supplied power at a frequency of greater than 500 MHz, preferably between 700 MHz and 1 GHz.

9. The RFQ accelerator of claim 1 , further comprising one or more adjustable tuners for adjusting magnetic field distributions, each of said adjustable tuners being adjustable by means of a screw gauge.

10. The RFQ accelerator of claim 9 wherein each said adjustable tuners have a tuner head with an at least partially conical shape, the partially conical shape having a rounded tip.

11. The RFQ accelerator of claim 10 wherein the partially conical shape has a height to radius ratio of between three-fifths and four-fifths, and preferably two thirds.

12. The RFQ accelerator of claim 1 , wherein the RFQ accelerator is less than 6 m in length, preferably 5 m, and the output energy is at least 7 MeV, preferably between 10 MeV and 12 MeV.

13. The RFQ accelerator of claim 1 , wherein the RFQ accelerator is less than 3 m in length, preferably 2 m, and the output energy is at least 4 MeV, preferably 5 MeV.

14. The RFQ accelerator of claim 1 , wherein the RFQ accelerator comprises at least two resonant cavities, each of the at least two resonant cavities being separated from adjacent resonant cavities by a drift region between vanes.

15. The RFQ accelerator of claim 1 , wherein the accelerated charged particles comprise any of one of protons, deuterons and alpha particles.

16. A method of accelerating charged particles using a compact radio-frequency quadrupole ‘RFQ’ accelerator, the method comprising:

capturing at a bunching section only a portion of a particle beam incident on the bunching section, wherein the bunching section is configured to have a narrow rf acceptance such that only the portion of the particle beam is captured;

bunching the portion of the particle beam at the bunching section;

accelerating at an accelerating section the bunched portion of the particle beam to an output energy; and,

supplying radio-frequency power by a means for supplying radio-frequency power.

17. The method of claim 16 , the method further comprising producing at least one of technetium, astatine and fluoride by accelerating charged particles at target substances using the RFQ accelerator.