Development of movable mask system to cope with high beam current

Suetsugu, Y.; Shibata, K.; Sanami, Toshiya; Kageyama, T.; Takeuchi, Y.

doi:10.1063/1.1583860

Cited by 6 publications

(11 citation statements)

References 7 publications

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“…If the length of the mask head is 90 mm, the ratio of that to the radiation length is about 1.2, which is almost the same as that used in KEKB (40 mm Ti head, where the radiation length of Ti is 36 mm [25]). On the other hand, when an intense highenergy beam hits the mask head directly, the deposited energy is likely to cause a groove on the head [6,7]. Al 2 O 3 has a melting point of over 2000 C, and is said to be available up to about 1700 C. The melting point is higher than that of the titanium (1670 C).…”

Section: Basic Conceptmentioning

confidence: 96%

“…The trapped mode could be a source of discharge near the mask head, heating of the mask head and the support, and also excitation of any beam instability [1,3,[5][6][7]11]. The HOM absorber, however, can be a HOM source, itself, and so the quantity of the absorber should be as small as possible.…”

Section: Basic Conceptmentioning

confidence: 99%

“…Another problem of the movable mask is damage to the mask head due to direct hitting of the intense beam, where copper or titanium has usually been used as a head material [1][2][3][4][5][6][7]. The beam deposits energy in a narrow area of the head, which can melt it.…”

Section: Introductionmentioning

confidence: 99%

“…The movable mask, therefore, has inherently a high beam impedance [1][2][3][4][5][6][7][13][14][15][16][17][18][19][20]. Actually, the present movable masks have caused excess heating of adjacent vacuum components, such as the bellows chambers, gate valves, and pump elements, due to the excited higher order modes (HOM) [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…A movable mask (or collimator) is a special vacuum component for particle accelerators to cut off spent particles around a nominal beam orbit, and then to decrease the background noise of the particle detector [1][2][3][4][5][6][7]. The movable mask is an indispensable vacuum component for high luminosity machines, such as various factories at present or in the future [8][9][10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

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Design study of a movable mask with low beam impedance

Suetsugu

Shibata

Morishige³

et al. 2006

Phys. Rev. ST Accel. Beams

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A novel design of a movable mask (collimator) for high-current accelerators is proposed. The mask head is supported by a ceramic rod to reduce interference with the beam. One side of the support is coated with a thin ( 1 m) conductive material to avoid extra charge up of the head. The head is also made of ceramics to avoid direct damage from an intense beam. To investigate the availability of the new movable mask, the rf properties, such as the impedances of trapped modes and the loss factors, were evaluated by simulation codes. The frequencies and the Q values of the trapped modes were also measured using a test model, and compared with calculated ones. Two trial modes for KEKB are being manufactured, and will be tested with beams next year.

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Section: Basic Conceptmentioning

confidence: 96%

Section: Basic Conceptmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Design study of a movable mask with low beam impedance

Suetsugu

Shibata

Morishige³

et al. 2006

Phys. Rev. ST Accel. Beams

Self Cite

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Development of a bellows chamber with a comb-type RF shield for high-current accelerators

Suetsugu¹,

Shirai²,

Shibata³

et al. 2004

Nuclear Instruments and Methods in Physics Research Section A:

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Development of bellows and gate valves with a comb-type rf shield for high-current accelerators: Four-year beam test at KEK B-Factory

Suetsugu

Kanazawa

Shibata

et al. 2007

Review of Scientific Instruments

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Since a comb-type rf shield was proposed in 2003 as a rf shield for future high-intensity accelerators, various types of bellow chambers and gate valves with this rf shield have been installed in the KEK B-Factory rings in series and tested with beams. Through beam tests to check the performance, a structural simplification has been tried in parallel. The temperatures of the bellow corrugations decreased by a factor of 3-6 compared to those with a conventional finger-type rf shield in most cases. The temperatures of the body of the gate valves also decreased by a factor of 2-5. These results demonstrated the availability of the comb-type rf shield. Although a discharge was observed in one simplified model, the latest model has shown no problem up to a stored beam current of 1.8 A (1.3 mA/bunch, 6 mm bunch length). Experiences with the comb-type rf shield in these four-year beam tests are reviewed here.

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Development of movable mask system to cope with high beam current

Abstract: Application of a sawtooth surface to accelerator beam chambers with low electron emission rate

Cited by 6 publications

References 7 publications

Design study of a movable mask with low beam impedance

Design study of a movable mask with low beam impedance

Development of a bellows chamber with a comb-type RF shield for high-current accelerators

Development of bellows and gate valves with a comb-type rf shield for high-current accelerators: Four-year beam test at KEK B-Factory

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