Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Results of the LH2 target test

HISPEC-DESPEC meeting 28th February 2012

Corinne Louchart, CEA Saclay

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Characteristics of the LH2 target:

� 20 mm thickness (for the test), 60 mm thickness also developed

� 65 mm diameter

� 125 µm of mylar for the entrance window

� 250 µm of mylar for the exit window

Exit window

Entrance window

The LH2 target

Filling of liquid hydrogen (test in CEA Saclay)

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Installation on the roof

� control – command

� H2 and N2 gas tanks

� cables and gas pipes from roof to vault

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Installation in S4

� target installation ~ 1h

� pumping time ~ 10h

� cooling time ~ 15h

Operation time: ~ 24 h

De-installation time: ~ 12 h

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

In-beam test set-up

Beam of 54Cr at 130MeV/u

� 7 hours of beam time

� 400 000 particles per spill (10 s)beam

RIS

ING

TPC TPC TPC

MUSIC MUSIC

START STOP

LYCCA Si

LYCCA CsI

Hecto

r

No target DSSD

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Identifications

Energy CsI (MeV)

En

erg

y D

SS

D (

MeV

)

� MUSIC 2 used

Z

A/Q

Beam selection

54Cr

Z selection

Cr

Ti

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

IdentificationsT

oF

(a

.u.)

Total kinetic Energy (MeV)

54Cr

52Cr

48Ti

Mass

� absolute mass obtained via E = γmc2

� Mass resolution ≈ 1.0 (FWHM)

Cr isotopes

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Ge time gate

Ge time (a.u.)

54Cr

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Background versus detector position

Cos(ααααγγγγ)

54Cr

En

erg

y (

keV

)

Energy (keV)Energy (keV)

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Energy spectra

2+→ 0+

@ 834 keV

4+→ 2+ and

Contamination 53Cr

Energy (keV)

Co

un

ts (

10

keV

/bin

)

Energy (keV)

Co

un

ts (

10

keV

/bin

)

5/2-→ 3/2-

@ 1007 keV

� E resolution ≈ 30 keV (FWHM)

� S/B ≈ 2

7/2-→ 3/2-

@ 1288 keV

Contamination 52Cr

Inelastic scattering (p,p’)

Knockout -1n0+

2+

4+

6+

8+

10+

12+

834.8 keV989 keV

1398.6 keV

1459.1 keV

2042.5 keV

2101.2 keV

1006 k

eV

3/2-

1973.6

keV

1/2-

5/2-

7/2-

5/2-

7/2-1289.6

keV

530.2

keV

564 k

eV

H.J. Wollersheim et al.

NIM A 537 (2005) 637-657

55Ni + 9Be @171 MeV/u

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Energy (keV)

Co

un

ts (

10

keV

/bin

)

Energy (keV)

Co

un

ts (

10

keV

/bin

)

2+→ 0+

@ 887 keV

4+→ 2+

@ 1310 keV

2+→ 0+

@ 1436 keV

4+→ 2+

@ 932 keV

Energy spectra

Knockout -2p -4n

Knockout -2n

0+

2+

4+

1434.1 keV

935.5 keV

0+

2+

4+

983.5 keV

1312.1 keV

H.J. Wollersheim et al.

NIM A 537 (2005) 637-657

55Ni + 9Be @171 MeV/u

Corinne Louchart – LH2 target test NUSTAR meeting – 28/02/2012

Conclusions

To be done (In-beam test analysis):

� Addback for Ge clusters

� Estimate efficiencies via G4 simulations

� Cross section estimates

� Technical article/report to be written

Conclusion:

� PRESPEC H2 target operational

� Available thicknesses: from 20 to 60 mm

� In-beam validation successful

� Inelastic, n and p knockout measured

� S/B up to 3 for -2n knockout

� Mass ID: ∆A/A=1 FWHM (preliminary)