I I A , C A - - PDF document

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I I A , C A - - PDF document

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1 2 3 2 4 I I A , C A B A

slide-1
SLIDE 1

日本物理学会 春の分科会 平成 1 2 年 3 月 2 4 日 於 関西大

東大院総合

A、東大院理 B

、理研

C

、科警研

Ｄ、デブレツェン大 E

市岡 利康

A , C

、檜垣 浩之

A、堀

正樹

B

、吉城F r a n z én 健

A、

黒田 直史

A、U

j b a r i B a l áz s

E

、大島 永康

C

、毛利 明博

C

、 黒木 健郎

Ｄ、小牧

研一郎

A、山崎

泰規

A , C

超低速反陽子実験のための 荷電粒子蓄積トラップの開発 I I

slide-2
SLIDE 2

発表内容 （１）A S A C U S A トラップ （設計思想・性能） （２）回転電場による 電子プラズマの制御 （３）H

  • イオンの閉じ込めと電子冷却

（４）まとめ 今後の実験計画

slide-3
SLIDE 3

For an antiproton, this is given : B r e- + p spheroidal plasma

The Brillouin limit

ω rp E Electron density should not exceed the Brillouin limit of antiproton Radial force balance on a charged particle with mass m, charge e :

– mv2 r = –eE + evB – v r

2

= –1 2 e2n mε0 + eB m v r ω

r 2 + 1

2 ωp

2 –ω cω r = 0

ω

c 2 ≥ 2ωp 2

From : v = rω

r, E =enr

2ε0 np [cm-3]

2.6 x 109 1.3 x 1010 5 1 B[T]

n ≤ ε0B 2m

(The Brillouin limit)

slide-4
SLIDE 4

Profile change by an application of rotating E-field

30sec 60sec 120sec e

  • ～

1 . 3 x 1

8

p r e s s u r e ～ 1 . 6 x 1

  • 9

T

  • r

r

slide-5
SLIDE 5

Profile difference by total charge

1.3 x 10

7

e

  • 3.6 x 10

7

e

  • 5.4 x 10

7

e

  • p

r e s s u r e ～ 1 . 2 x 1

  • 9

T

  • r

r 6 s e c w a i t + 6 s e c r

  • t
  • E
slide-6
SLIDE 6

ASACUSA Trap design

# One segmented electrode # Cylindrical electrodes # Central harmonic potential region ~ 10cm # Oxygen free copper # AlN (high thermal conductivity) # Trap length = 50cm (Harmonic region = 10cm) # Penning type trap # Harmonic potential well # 10µm precision # Gold plating * Control of plasma shape and density by rotational RF field * Injection from RFQ * Extraction of stored antiprotons * ne + np < 1.3 x 1010

( Brillouin limit of )

p * Vacuum in the magnet bore ~ 10-12 Torr or better * Pulse length of 50keV antiprotons from the RFQ = 300ns * Stable storage and cooling of 106~8 antiprotons * Monitoring of plastma modes

solutions Requirements

# LabView + GPIB + CAMAC * System control from outside the area

slide-7
SLIDE 7

e- only H- + e- ; 5.7 sec H- + e- ; 2.7 sec H- + e- ; 4.2sec 50µs

H– injection Ejection

  • 900V
  • 1085V
  • 1500V
  • 1400V

0V H– ions Eaxial : 800~1000eV

H- cooling : raw signals

p

  • t

e n t i a l c h a n g e H- + e- ; 4.2sec H- + e- ; 2.7 sec H- + e- ; 5.7 sec e- only

slide-8
SLIDE 8

Time distribution of extracted H- (H- only)

  • 0.005

0.005 0.01 0.015 0.02 0.025 0.03

  • 5 10-5

5 10-5 0.0001 0.00015 0.0002 0.00025

time (sec)

2.9 sec 12.7 sec 5.7 sec H

  • s

i g n a l a n d i t s d i f f e r e n c i a t i

  • n
slide-9
SLIDE 9
  • 0.01
  • 0.005

0.005 0.01 0.015 0.02 0.025 0.03

  • 5 10
  • 5

5 10

  • 5

0.0001 0.00015 0.0002 0.00025

Time distribution of extracted H-

time (sec)

H- only ; 2.9 sec H- + e- ; 5.7 sec H- + e- ; 2.9 sec

H- ～ 2x106 for H- only, 2.9 sec trapping e- ～ 1.5x108, loaded 70 sec before H- injection

slide-10
SLIDE 10

H- ～ 2x106 e- ～ 9x107 no rot-E : electrons loaded 70 sec before H- injection with rot-E : 60 sec wait 120 sec rotating field at 2MHz, 0.5V 30 sec wait before H- injection

  • 0.005

0.005 0.01 0.015 0.02 0.025 0.03

  • 5 10
  • 5

5 10

  • 5

0.0001 0.00015 0.0002 0.00025

Trapping time = 2.9 sec Time (sec)

H- only H- + e- ; no rot-E H- + e- ; with rot-E

H- cooling with/without rotating field

slide-11
SLIDE 11

Change in the profile

0.5MHz, 0.5V 2.0MHz, 0.5V 1.5MHz, 0.5V 1.0MHz, 0.5V 2.5MHz, 0.5V 3.0MHz, 0.5V e

  • ～

1 . 3 x 1

8

6 s e c w a i t + 6 s e c r

  • t
  • E
slide-12
SLIDE 12

Ion beam line

t

  • t

h e T r a p D u

  • p

l a s ma t r

  • n

I

  • n

s

  • u

r c e D i p

  • l

e ma g n e t E i n z e l l e n s B e a m c h

  • p

p e r A c c e l e r a t i

  • n

t u b e E i n z e l l e n s e- : ~100 eV H- : ~1.0 keV p+ : ~50 keV

slide-13
SLIDE 13

0.005 lx, 1000V acceleration => 4 x 107 electrons can be detected.

Luminescence detection scheme

CCD : Rox 40 (1/2 inch) 0.005 lx (F1.2, normal mode) 0.0005 lx (F1.2, high sensitive mode) Image size : 5~6° => Zoom lens (12.5 - 75 mm ; F1.8) Degital video : DCR-TRV900 8 lx (F1.6) > 100 lx (recommended) ZnO : emmision peak at 505nm 1/10 decay time : 4~500 ns ITO : 10Ω transmission = 87% at 500nm can also be used as a F.C. PC H-,e-

slide-14
SLIDE 14

( 1 ) A D a n d A S A C U S A p r

  • j

e c t P r

  • d

u c t i

  • n
  • f

me V ̃ e V a n t i p r

  • t
  • n

s i s e s s e n t i a l t

  • t

h e e x p e r i me n t s . ( 2 ) D e s i g n

  • f

t h e A S A C U S A t r a p p i n g s y s t e m

  • M

u l t i

  • r

i n g h a r mo n i c t r a p ( h a r mo n i c r e g i

  • n

～ 1 c m) E l e c t r

  • n

c

  • l

i n g

  • f

1

6 ̃ 8

a n t i p r

  • t
  • n

s A c t i v e c

  • n

t r

  • l

a n d mo n i t

  • r

i n g

  • f

p l a s ma ( 3 ) E x p e r i me n t w i t h e l e c t r

  • n

s

  • l

i f e t i me me a s u r e me n t > 1 s e c

  • C

e n t e r i n g

  • f

e l e c t r

  • n

p l a s ma s b y r

  • t

a t i n g E

  • f

i e l d : ø < 2 mm ( 4 ) S i mu l a t i

  • n

e x p e r i me n t s w i t h n e g a t i v e h y d r

  • g

e n s

  • e

l e c t r

  • n

c

  • l

i n g w a s

  • b

s e r v e d .

まとめ