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Performance of an electron gun for a high-brightness X-ray generator.

Sugimura T, Ohsawa S, Ikeda M - J Synchrotron Radiat (2008)

Bottom Line: Its extraction voltage and design current are 60 kV and 100 mA (DC), respectively.The X-ray generator aims towards a maximum brilliance of 60 kW mm(-2).The fabricated electron gun optimizes an aperture grid and a Whenelt electrode.

View Article: PubMed Central - HTML - PubMed

Affiliation: Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), Japan. takashi.sugimura@kek.jp

ABSTRACT
A prototype thermionic electron gun for a high-brightness X-ray generator has been developed. Its extraction voltage and design current are 60 kV and 100 mA (DC), respectively. The X-ray generator aims towards a maximum brilliance of 60 kW mm(-2). The beam sizes at the rotating anticathode must therefore be within 1.0 mm x 0.1 mm and a small beam emittance is required. The fabricated electron gun optimizes an aperture grid and a Whenelt electrode. The performance of the prototype electron gun measured using pulsed-beam tests is as follows: maximum beam current, 85.7 mA; beam focus size at the rotating anticathode, 0.79 mm x 0.13 mm. In DC beam tests, FWHM beam sizes were measured to be 0.65 mm x 0.08 mm at the rotating anticathode with a beam current of 45 mA. The beam current recently reached approximately 60 mA with some thermal problems.

No MeSH data available.


DC beam profiles on the anticathode. FWHM beam sizes are 0.65 mm × 0.08 mm with a beam current of 45 mA.
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fig9: DC beam profiles on the anticathode. FWHM beam sizes are 0.65 mm × 0.08 mm with a beam current of 45 mA.

Mentions: We added water-cooling tubes on the vacuum chamber near the anticathode and increased the power of the air compressor to 2.2 kW. These cooling systems reduced the temperature of the vacuum chamber by about 40 K. We have been increasing the beam current with care in terms of the temperature and vacuum pressure towards the goal current. Fig. 9 ▶ shows the beam profile at a beam current of 45 mA. Obtained FWHM beam sizes from the profile are 0.65 mm × 0.08 mm. Effective brilliance, which is defined here to be the average density of the beam power within an ellipse whose major and minor axes lengths are equal to the FWHM beam sizes, is 34 kW mm−2 under the assumption that the beam on the target has a two-dimensional Gaussian profile. Taking the total current of 45 mA into consideration, this value is mildly impressive. An increase in the beam current will deliver the expected brilliance. Recently a beam current of approximately 60 mA was achieved.


Performance of an electron gun for a high-brightness X-ray generator.

Sugimura T, Ohsawa S, Ikeda M - J Synchrotron Radiat (2008)

DC beam profiles on the anticathode. FWHM beam sizes are 0.65 mm × 0.08 mm with a beam current of 45 mA.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2394796&req=5

fig9: DC beam profiles on the anticathode. FWHM beam sizes are 0.65 mm × 0.08 mm with a beam current of 45 mA.
Mentions: We added water-cooling tubes on the vacuum chamber near the anticathode and increased the power of the air compressor to 2.2 kW. These cooling systems reduced the temperature of the vacuum chamber by about 40 K. We have been increasing the beam current with care in terms of the temperature and vacuum pressure towards the goal current. Fig. 9 ▶ shows the beam profile at a beam current of 45 mA. Obtained FWHM beam sizes from the profile are 0.65 mm × 0.08 mm. Effective brilliance, which is defined here to be the average density of the beam power within an ellipse whose major and minor axes lengths are equal to the FWHM beam sizes, is 34 kW mm−2 under the assumption that the beam on the target has a two-dimensional Gaussian profile. Taking the total current of 45 mA into consideration, this value is mildly impressive. An increase in the beam current will deliver the expected brilliance. Recently a beam current of approximately 60 mA was achieved.

Bottom Line: Its extraction voltage and design current are 60 kV and 100 mA (DC), respectively.The X-ray generator aims towards a maximum brilliance of 60 kW mm(-2).The fabricated electron gun optimizes an aperture grid and a Whenelt electrode.

View Article: PubMed Central - HTML - PubMed

Affiliation: Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), Japan. takashi.sugimura@kek.jp

ABSTRACT
A prototype thermionic electron gun for a high-brightness X-ray generator has been developed. Its extraction voltage and design current are 60 kV and 100 mA (DC), respectively. The X-ray generator aims towards a maximum brilliance of 60 kW mm(-2). The beam sizes at the rotating anticathode must therefore be within 1.0 mm x 0.1 mm and a small beam emittance is required. The fabricated electron gun optimizes an aperture grid and a Whenelt electrode. The performance of the prototype electron gun measured using pulsed-beam tests is as follows: maximum beam current, 85.7 mA; beam focus size at the rotating anticathode, 0.79 mm x 0.13 mm. In DC beam tests, FWHM beam sizes were measured to be 0.65 mm x 0.08 mm at the rotating anticathode with a beam current of 45 mA. The beam current recently reached approximately 60 mA with some thermal problems.

No MeSH data available.