Study of Electromagnetic Interactions of Light Ions in the Framework of the

IHEP Ion Program at U70

Serguei Sadovsky, IHEP, Protvino

EMIN-2009, Moscow, 19 September 2009

Outlook

IHEP accelerators Positroniy channel Possible physics domains Conception of experimental setup Conclusion

23 декабря 2008 Сессия-конф. СЯФ ОФН РАН 3

IHEP accelerators

U70 accelerator

Linac U30

Buster U1.5

Linac I100

Linac for light ion acceleration: I100

p, d ion source

3 м

TOF:ЦФ

HV generatorUp to +750 кV

p N+, O+ N2+,O2

+

2008

N2+,O2

+

p d

100 ns

50 mА p

15 mА d 5 mks 16.7 MeV/n

2008

Light ion source: I100 (laser source of 12C)

IHEP laser (CO2, 2.7 J, 10 m, 0.25 Hz) IGP of RAS laser (…, 10 Hz)

C+5

C+4

C+3

C+2

Рисунок 3

Beam of C5+

40 mA @ entry toI100

1.6 mA @ exit from I100

Light ions: channel from I100 to U1.5

17.11.06: p 72.7 MeV 01.12.06: d 16.7 MeV/n

Light ions: December 2008

d in U70 after 4 magnets

10–12.12.08; d; 16.7–> 455 MeV/n

April 2009: d-beam circulation in U70

Ion beam extraction from U70

5 mm

5mm

Si crystal station

1.71013proton p (U30)

3109carbon 12C6+

11011 deuteron d

2-91011 proton p ( I100 )

NB0Ions in U70

Proposal to study the ion beam extractions in «Positroniy» channel

Experimental area of «Positroniy» channel: two beam magnets and one of two secondary targets are proposed to install, the available Z distance is 15 m

tg1tg2

M1M2

Up to 106 12С/cicle in «Positroniy» channel is expected due to beam extraction with Si Crystal

Extraction efficiency is 0.1%

Crystal bended angle ~ 60 mrad

1.71013proton p

3109carbon 12C6+

11011 deuteron d

2-91011 proton p

NB0Ions in U70

Extraction efficiency vs banded angle

Intensities of secondary radioactive beams in 12С fragmentation

The secondary beam optics allows to have beams of different radioactive nuclei

At the intensity of 12C

primary beam I=3·109

/cycle the fragment intensities variate from I=106 /cycle for 8Li and to I=104 /cycle for 8He

1,9E+069999512,3 y3H

1,9E+069949,55stable3He

1,9E+071326650stable4He

7,4E+05198992807 ms6He

1,3E+042641320,035119 ms8He

1,5E+06198664stable6Li

2,6E+06231777stable7Li

8,9E+05264882,4840 ms8Li

1,9E+05297990,5178 ms9Li

4,4E+0623157,751253 d7Be

3,7E+0629774,2510stable9Be

2,2E+0633082,561,6 106 y10Be

5,2E+0526452,81,4770 ms8B

1,4E+073306638stable10B

2,6E+0736372,670stable11B

7,4E+0429749,50,2126 ms9C

7,4E+0533055219,3 s10C

2,0E+0736360,55320,3 m11C

Ionsper cycle

Momen-tum(GeV/c)

Rigidity

GeV/c)

σ (12C + 12C) → fragment (mb)

Life- timefragment

Important: the fragments have different rigidity =>fragments identification with Spectroscopic magnet is possible

Physics case 1: study of light nuclei at the limit of neutron stability

Light nuclei beyond the neutron stability

PHYSICS case 2: Nuclear Clastering of the 12С fragments, including short-leaved and exotics nuclei

9Li 178 ms 8Li 838 ms 6He 807 ms8He 119 ms

can be studied at U70

P.Zarubin, JINRLINC-2008

Nuclear ClusteringNuclear Clustering P.Zarubin, JINRLINC-2008

can be studied at U70

Angular distribution of fragments without spectroscopic magnet

16O + p -> 4He + X at 3.25 AGeV/c

V.V.Glagolev at al. 2001

Θ(25AGeV) ~ Θ(3.25AGeV)*3.25/25 => RFr > 1.7 cm at Z = 15 m

Excitation energy per nucleon, MeV

T109

K Liquid

Gas

PHYSICS case 3: phase transition in a cold nuclear matter ?

PHYSICS case 4: neutral meson photoproduction in AA-collisions

b) photoproduction

Coherence condition in the inverse kinematics:

-q2 < 1/Rtarget, i.e.

Eγ < γ/Rtarget = γ/1.2A1/3

Inverse kinematics of neutral meson photoproduction in the AA-collisions

Eγ (max) = γ/1.2A1/3 for 12C + 56Fe -> meson+X = and 25 AGeV/c 12C beam Ethr ~ Eγ (max) ~ mmeson γ = 26.6 Eγ(max) = 1140 MeV

Thus π0, η, ω , φ photoproduction is possible in the reaction 12C + 56Fe -> meson+X at 25 AGeV/c

The meson energy in the Lab frame is as follows:Emeson > γ mmeson, i.e.

E(π) > 3.6 GeVE(η) > 14.6 GeVE(ω) > 20.8 GeVE(φ) > 27.1 GeV

TrigBm = S1*S2*EPB(E<Ethr1)*EPSD(E<Ethr2)

PSD

LGD2 Magnet

Plastic Ball

target S2

S1

MWPC6

MWPC4

MWPC3 MWPC2 MWPC1

MWPC5

UrQMD simulation:C+C at 25A GeV/c,Total pz of beam fragments in lab

TrigTg = S1*S2*EPB(E>Ethr1)*EPSD(E>Ethr2)

Setup conception for the light ion fragmentation studies in ion-ion EM-interaction

Beam

WA98 plastic ball: fragment detection in the target reference frame

ξ=log1.95ΔE 0.95E0.5ΔE −11.226

Projectile Spectator Detector (PSD@CBM) for detection of the beam fragmentation

Spectator spots at Z=15m, EAu=15 AGeV,

simulation

Beam hole

XZ

Transverse sizes ~1x1 m2;

Distance from target - 15 m;

Number of modules – 107;

Module dimensions – 10x10x160 cm3

A.P.Ivashkin 2008, INR RAN

PSD for CBM, design, construction and beam test results:

• Modular Lead/Scintillator sandwich compensating calorimeter

• Sampling ratio Pb:Scint=4:1

• Expectation: For thickness δPb=16 mm and δScint=4 mm σE/E ~ 50%/√E

• 60 lead/scintillator sandwiches.

• 10 longitudinal sections

• 6 WLS-fiber/MAPD

MAPDs and amplifiers

A.P.Ivashkin 2008, INR RAN

measurements

Spectroscopic magnet in the experimental aria of the “Positroniy” channel (JINR) and DC

Lead Glass Detector LGD2 (IHEP, Hyperon setup)

Conclusion

• Ion beams at U70 accelerator are expected for users in 2010-2011

• The expected intensity of 12C beam in “Positroniy” channel is up to 106/cycle

• Different radioactive light ion beams can be created on the base of carbon beam with momentum of 25-30 AGeV/c

• An essential part of experimental equipment exists and could be used in the future experimental setup for 12C+A interaction studies

• This opens several quite interesting physics domains for experimental studies, including light nuclei at the limit on neutron stability, EM fragmentation of light radioactive nuclei, phase transition in a cold nuclear matter and neutral meson photoproduction

• Welcome to participate in the experiment