outline concept development of a he - beam development of a heh + beam
DESCRIPTION
R & D Status of Beam Neutralization System M. Sasao, K. Shinto, M. Okamoto, S. Kitajima, N. Tanaka, M. Nishiura, O. Kaneko, H. Sakakida, and M. Wada Tohoku Univ. NIFS, AIST,and Doshisha Univ. OUTLINE Concept Development of a He - beam Development of a HeH + beam - PowerPoint PPT PresentationTRANSCRIPT
R & D Status of Beam Neutralization System
M. Sasao, K. Shinto, M. Okamoto, S. Kitajima, N. Tanaka, M. Nishiura, O. Kaneko,
H. Sakakida, and M. WadaTohoku Univ. NIFS, AIST,and Doshisha Univ.
OUTLINE
Concept Development of a He- beam Development of a HeH+ beam Measurement of He* fraction Summary and Future work
2/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Concept of a He- beam
Beam dump
Analyzer
BeamSource
26 m
He++ + He0 => He0 + He++
Typical Beam parameter:He0, from auto-detached He-, 10 mA, 5cm x 20cm, 0.1 mA/cm2
Accelerated up to 1.5-1.8 MeVHe0 in the ground state
He++ + He0 => He0 + He++
Measuringpoint
RFQ + HV stage (above)1m x 1m + 1m x 1m x 3m
Detectionpoint
3/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Development of a He- beam (1) M. Sasao, K. Shinto, et al.
• Pencil beam system for POP Pencil beam system for POP – Optimization of HeOptimization of He++ beam beam– Characterization of beamsCharacterization of beams– Optimization of Alkali gas cellOptimization of Alkali gas cell– Phase space change by charge Phase space change by charge
exchange cellexchange cell– Optimaization of Beam opticsOptimaization of Beam optics– Measurement of metastable fractMeasurement of metastable fract
ionion
• Full Size He+ sourceFull Size He+ source Test at NIFS NBI test standTest at NIFS NBI test stand
• SDS(System Design Study) foSDS(System Design Study) for r ITERITER
MilestonesMilestones
Ion source
Double focus mass separator/lens
He+ beamlets
Main acceleration
Lens
Na/Rb cell
Lens
Free flying tube
Tohoku Univ. HeTohoku Univ. He-- Test System Test System
10 mA He+He-,He0
He+
10 A He-
4/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Development of a He- beam (2)
Pencil beam system for POPPencil beam system for POP
絶縁碍子上に高圧ステーションを構成 (100-200kV)
He+ イオン源アルカリ
金属ガスセル
偏向電磁石
飛行管用貫通孔(隣の実験室へ)
5/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Development of a He- beam (3)
Full Size modelFull Size model
絶縁碍子上に高圧ステーションを構成 (100-200kV)
He+ イオン源アルカリ
金属ガスセル
偏向電磁石
飛行管用貫通孔(隣の実験室へ)
6/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Concept of a HeH+ beam
Typical Beam parameter:He0, from a HeH+, 20 mA, 5cm x 20cm, 0.2 mA/cm2
Accelerated up to 1.5-1.8 MeVHe0 in the ground state
Measuringpoint
RFQ + HV stage (above)1m x 1m + 1m x 1m x 3m
DetectionpointProduced He0 beam energy (keV)
HeH+
2 mA/cm2He0
0.2 mA/cm2
SeparationAcceleration
Neutralization 10%
7/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Development of a HeH+ beam H. Sakakida, et al.
In the case of high energy 25 keV beam, if
15 % of the total current of 40 A, (which in
cludes H+, H2+, H3
+, He+ and HeH+ compon
ents) is the HeH+ component, the current
density of HeH+ is ~13 mA/cm2, which is s
ufficient for the primary beam in the meas
urement of ITER.
The conditions producing HeH+ beam were not inves
tigated in detail as yet. Therefore, the optimum condit
ions to extract HeH+ beam have been explored using
our beam system.
In order to measure beam species, mass spectromet
er, whose energy range is limited less than 500 eV, is
used. Therefore, DC power supply of 300 V is used fo
r the beam acceleration (here, -4.5 kV is applied to
the deceleration electrode for efficient beam extractio
n). Figure shows the number of HeH+, He+ and H+ ions
as a function of He gas pressure ratio to the total gas
pressure of the mixture gas (He and H2) in the case of
low energy 300 eV and ~6 A beam. It is clear that the
production rate of HeH+ increases, when He pressure
ratio is larger than ~75 %. In the case of 90 % ratio, th
e number of HeH+ particles corresponds to ~15 % of t
otal counts for HeH+, He+ and H+ ions.
8/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Measurement of He* fraction M. Okamoto
9/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Summary and crucial issues
• Development of a He- beam is on going in 3 sub-groups in parallel,
[1] Pencil beam system for Proof Of Principle[1] Pencil beam system for Proof Of Principle
[2] Full Size He[2] Full Size He++ source source
[3] System Design Study for ITER[3] System Design Study for ITER
• The option of a HeH+ source is promising as an alternative probing beam.
• Several measurement methods of He* fraction are proposed and their principles will be tested.
10/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Summary and crucial issues
• Development of a He- beam is on going in 3 sub-groups in parallel, [1] PenPencil beam system for POPcil beam system for POP
[2] Full Size He[2] Full Size He++ source source [3] System Design Study for [3] System Design Study for ITERITER
• The option of a HeH+ source is promising as an alternative probing beam. • Several measurement methods of He* fraction are proposed and their princi
ples will be tested.
• It is crutial to keep a tangential port at #6.• Is it possible to send the argument- from diagnostic point of veiw?(although 99% is on the current drive, and blanket test.)Example:Various important phenomena which should be studied on ITER require 2D ima
ging.
A tangential port can be used for various 2D imaging (X-ray, VUV, visible, bolometric, neutrons, gamma’s, etc.), in addition to the beam alpha-particle diagnostics.
11/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Summary and Future work
• It is crutial to keep a tangential port at #6. -
12/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
13/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Conclusion
14/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Conclusion
15/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Conclusion
16/1410th ITPA diagnostics meeting , Moscow 10-14/04/06 M. Sasao
Conclusion