23 July 2010 FLNR Dubna

Summer Summer StudentsStudents Practice PracticeFlerov Laboratory of Flerov Laboratory of NuclearNuclear Reactions, Reactions,

JINR, JINR, DubnaDubna 2010 2010

Studies with radioactive ion beams at fragment separators

23 July 2010 FLNR Dubna

student:Maciej Mikulski (UJ)

and his supervisor:dr Grzegorz Kaminski

23 July 2010 FLNR Dubna

Main goals:

learn how to produce Radioactive Ion Beams (RIBs)

get practical knoweledge about neutron detectors

make friendship with Lise

identify nuclei from experimental data

get familiar with object of experiments at in-flight separator

23 July 2010 FLNR DubnaFLNR Dubna

the Acculinna Group is studying the properities and the structure of lightest nuclei

23 July 2010 FLNR Dubna

cocktail of isotopes

beams: a few teens of MeV-GeV

very short living nuclei > 1 s

beams: keV-GeV

time of life limitation > 0.1 s

pure beams

Two main methods of producing exotic beans:• Isotope Separation On-Line (ISOL)• In Flight

23 July 2010 FLNR Dubna

thin targetprimary beam

E ~ a few teens MeV/A

TOF – Time Of Flight

B - magnetic rigidityB – vector of magnetic field

- radius of particle trajectory

degrader dE – energy losses

start stopdetectors

BB11 < B< B22<< BB33

BB11

BB22

BB33

In-flight example

Measurements on 11B beam @ 32.9AMeV

Measurement method

~0.13% dp/p

11B 33 AMeV

9Be (14 mg/cm2) 27Al (17 mg/cm2) 197Au (9 mg/cm2)

beam

Si 300 m 16x16 stripsSi 1mm 16x16 stripsCsI/PD 4 units

two sytmetrical magnetic sections:

dispersive&achromatica slit instaled in

dispersive focal plane to increase the momentum

resolution

Magnetic field scanning

experimental data

simulations from Lise++

this let us identify nuclei

23 July 2010 FLNR Dubna0.5 1.0 1.5

10-3

10-1

101

103

105

0.5 1.0 1.510-3

10-1

101

103

105

0.5 1.0 1.510-3

10-1

101

103

105

10C

11C

8B

11B +

9Be

LISE

10B

11B12

B

7Be

9Be

10Be

11Be

6Li

R.Y

.

7Li

8Li

9Li

4He

vfrag

/vbeam

6He

8He

2 20(v-v ) /2 rel

dNBe

dv

23 July 2010 FLNR Dubna

0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

500

1000

1500

2000

2500

3000

3500

4000

Deep Inelastic component

experiment gaussian

Re

lativ

e Y

ield

s

vfrag

/vbeam

7Li

Direct (breakup) component

0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Velocity distributions: DIC & DIRECTcomponents

Each of this components relates to diffrent reaction mechanism.

Measurements on 32S beam @ 50.3AMeV

Measurements on 32S beam @ 50.3AMeV

32S @ 50 AMeV

9Be, 500m

Wedge 9Be, 500m& momentum slit

Plastic scintilator& momentum slit

Beam of isotopes at B close to 26S

detectors

ΔE-ToF identification plots for the cases of separator tuning on 27S (a) and 26S (b)

Measurements on 32S beam @ 50.3AMeV

No events of 26S and 25P !!!

Time of flight (TOF) of 26S too longNot optimal configuration target & wedge thickness – too thick

Measurements on 32S beam @ 50.3AMeVPractice goal: find better configuration of target&wedge for new measurements on 32S beam – a compromise between 26S energy (TOF), target and wedge thickness and data acquisition dead time

wedge 100μm

wedge 200μm

wedge 300μm

wedge 500μm

neutron detectors

23 July 2010 FLNR Dubna

voltage divider

photomultiplier

stilbene cristal

neutron detector

23 July 2010 FLNR Dubna

5H 8He 10He 11Li 14Beneutron multi detector of 64

modules is beeing constructed, now we have 32 stibene crystals

80 x 50 mm3

23 July 2010 FLNR Dubna

each of us mounted a

few modules

special thanks to my always friendly and patient supervisor

23 July 2010 FLNR Dubna

and to hard-working and ready to help organizators of this practise