LASER SOURCE OF POLARIZED PROTONS

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LASER SOURCE OF POLARIZED PROTONS

A. Zelenskii, S. Kokhanovskii, V. Lobashev, V. Polushkin

To cite this version:

A. Zelenskii, S. Kokhanovskii, V. Lobashev, V. Polushkin. LASER SOURCE OF POLARIZED PRO- TONS. Journal de Physique Colloques, 1985, 46 (C2), pp.C2-699-C2-701. �10.1051/jphyscol:1985288�.

�jpa-00224607�

JOURNAL DE PHYSIQUE

Colloque C2, supplément au n°2, Tome <f6, février 1985 page C2-699

LASER SOURCE OF POLARIZED PROTONS

A.N. Z e l e n s k i i , S.A. Kokhanovskii, V.M. Lobashev and V.G. P o l u s h k i n Institute for Nuclear Research, Academy of Sciences of the USSR, Moscow, U.S.S.R.

Heaume - Dana cet article sont présentes des résultats du développement de la source laser des protons polarisés.

Actuellement dans cette source on a obtenu 200 uA l'inten- sité' du faisceau des protons polarises avec la polarisa- tion 65±5ff.

Abstraot - She results of the development of a laser source of polarized protons are presented. Today in this source 200 M.A pulse intensity of polarized protons is obtained with polarization (>5±5%.

The new type of polarized protons source has been developed for Moscow Meson Factory. At this linear accelerator there is * fea- sibility of the simultaneous acceleration of protons and negative hydrogen ions H~. The laser source of polarized ions, which uses a charge-exchange reaction between a proton beam and electron spin polarized sodium atoms, should give rise to the increase of the polarized beam current in some mA range, and ST intensity up to 0.1 mA /1,2,3/.

likil aJ_5j M xJ iTUje/

—1 1

Pig.1 - Schematic layout of the laser source of polarized protonst 1,2,3 - source of neutral atoms; 4,8 - pulsed solenoids; 5,9 - helium ionizing cells; 6,11 - M a cells; 7 - deflecting plates;

12 - spin filter; 13 - H(2S) detecting system; 14 - Paradey cup;

15 - bending magnet; 16 - laser system.

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1985288

C2-700 JOURNAL DE PHYSIQUE

!&e main f e a t u r e of the device i a the u t i l i s a t i o n of an intenae eource of neutral atoma and an auxiliary ionizing helium c e l l (Fig.1). The c e l l i a put i n t o the magnetlc f i e l d of the solenoid together with the c e l l of oriented aodium vapours. So the &if- f i c u l t y of the emittance growth is ovemome. I n t h i e aaae the Snput and output beema are In neutral a t a t e and no emittancre growth i a induced by the solenoid eage f i e l d . !l%e proton y i e l d

is 80% f o r helium. m e protona produced i n the c e l l are retarged by 1 kV potential applied t o the g r i d electrodes. Ehis i a made

t o r e j e c t a non-polwized proton beam which i s formed from neut- rals passing through the f i r a t c e l l without ionization by energy aeparatlon and by deflection t o a diaphragm in a bending magnet.

The protons produced i n the c e l l pick up polarized electrone from m d i u a$oma in the e e l l . Eleotron spine of Bia atoma beoome polwised when atoms are o p t i o d l y oriented by o i r c u l a r l y pola- r i s e d emieaion of a flaah-lamp-pumped dye l a s e r tuned at the wavelength 5896 A which eomceaponds t o the t r a n a i t i o n 35 - ^32.

For measurezmnt of the eodium repin e l e c t r o n p o l a r i s a t i o n t h e method of analyaia of the spin-atatea of metastable hydrogen

atoma has been developed /3/. I n ^Fig.2 the dependence of pola- r i z a t i o n on the t a r g e t thiokneas i e ahom. Sinoe an e l e c t r o n transfered from odium t o hydrogen conaexves i t 8 apin direction, hydrogen atom8 produced by the charge-exchange are p o l w i s e d

along the electron ap-. !l!he deflecting p l a t e s are t o c l e a r out the charged p a r t i c l e a from the beam. Electron-spin polarization of hydrogen atoms i s transfered t o nuolear polarization by a Sona t r a n s i t i o n in a zero-oroeaing magnetic f i e l d . Ionization of atoma proceeds i n the second helium c e l l .

For proton polarisation meaeurement the charge-exchange of pro- tons Into metastable H(28) a t a t e a is used i n s eodium c e l l , me population of hyperf ine eublevels of H(2S) depends on proDon po1arieation.h analyaia of the epin e t a t e e d i a t r i b u t i o n of fi(2S) beam i a r e a l i s e d by means of transmission of t h e beam

through a epin f i l t e r and deteotion of the difference in a count r a t e of Lyman-d. detector which is connected with a v a r i a t i o n of the proton polarisation &Lrection./4,5/.

RESULPS /5/

'Phedependence of proton current and polarisation on aodium

c e l l temperature is presented in PAg.2 ( B m 1 0 kff, 3-1 kO), A t

the tempera ure oopeponiling t o the eodiuen vapour density of

about 3-3015 atla. the sodium polarization i a 908, the proton

current is 200 PA. The h t e n a i t y of 7 key n e u t r a l beam paaaed

through the polarizer i s about 5 mA, i t was measured by the

ionizing of the beam i n the second helium c e l l . The s u b s t a n t i a l

Zosaes of polarized proton current occur i n a long gap between

the i o a l z e r and the bending magnet i n which the sodium polari-

meter is placed. The optimieation of the i n s t a l l a t i o n geometry

and the improvement of the n e u t r a l beam aource should %ncreaee

the current up t o 1 mA, !the values of proton polarization at

d i f f e r e n t magnetio f i e l d s have been measured. The polarisation

grows with inoreasing of B1 and achieves 65*5% at B1=lS kG.

Big.2r f - ^{Spin electron eodium} polarization a a function of .ell temperature; Solid line - ^{Proton ourrent;} 1 ^{- Pmton}

polarization,

I

I) f.0 2!o 7'

Pfg.3t Meaeured proton polarisation at different Jna&netie field8 in the eodfum oell.

1, L.W.Anderaon, - ^{BUI, 167, 363 (1979)}

2, A.Zelenakii, S.EokhoPavukii, - ^{Proc. of the} 1nt.Sylap. on Pola- rization Phenomena i n fUgh Energy Pbyeics, Dubna, USSR, Bovember

1981, Dub=* D l , 2-82-27, 1982, 9.234

3. A,Zelenekii et al, - ^Pie*mn Zh.Bkep.Teor.Fi8. 36.12, p.21 1982 4. _5. Y.Plie, L.Soroko, - ^{hribory i te-a exep 3, p.44 619773}

A. Zelenekil, S.gakb4uroveLii - ^{m a . of the Int.} Workshop on

Spin Phenomena in iUgh Energy Phyalee,Protvino, Ootober 1983,

SeWUkho~ 1981, pa39