the intensity and the shape of the deuteron beams on kvinta...

1

The intensity and the shape of the deuteron beams on Kvinta

Gamma-3 targets (experiment March 2011) – preliminary

results from the Řež group

M. Suchopár, O. Svoboda, V. Wagner,

[email protected], [email protected], [email protected]

Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, Řež near

Prague, 250 68, Czech Republic

The experiments were carried out at the superconducting, strong focusing synchrotron named

Nuclotron with the deuteron energy 2, 4, 2.33, and 6 GeV on the Kvinta and Gamma-3

installations. The irradiations were performed between 6. – 23. March 2011. The course of the

irradiations is on Fig 3 - Fig 6. The irradiation lasted between 18 and 22 hours. Beam

intensities and profiles were measured by more E&T RAW groups, preliminary results of the

measurements done by Czech group are described in this paper.

Beam intensity determination The total beam intensity was determined by the activation analysis method using activation

foil from 27

Al. Other activation materials could not be used due to missing cross-section or

improper gamma-ray properties and half-life.

Al foil for the beam intensity measurement was placed on the beam tube window – on the

place of beam exit. In the process of irradiation, stable isotope 27

Al was transmuted by

(d,3p2n) reaction into radioactive 24

Na isotope. Measurements of other possible isotopes (7Be

or 22

Na) were not yet performed. The yield (i.e., the number of nuclei activated in the foil

during the whole period of the irradiation) of produced gamma-radioactive nuclei was

determined with the help of gamma-spectroscopy. Original dimensions of the foil were

10x10x0.0196 cm3, the foil was packed to a smaller one with dimensions approximately

2.5x2.5x0.3 cm3 for the spectroscopy measurement.

Activated foils were measured on four detectors, in five different geometries marked p2, p3,

p4, p5, and p6 which were 2.4, 4.1, 6.5, 9.9, and 14.7 cm far from the detector. The detectors

were calibrated using standard laboratory 54

Mn, 57

Co, 60

Co, 109

Cd, 133

Ba, 137

Cs, 152

Eu, 228

Th,

and 241

Am point sources which have several gamma-lines ranging from 80 keV up to

2610 keV. Calibration was measured before the experiment. Evaluated calibration activities

include correction on real coincidences at isotopes with more lines. Total number of points

used for one calibration curve is more than 35. Calibration curves are a three order

polynomials divided into two parts, one for lower energies and one for higher energies.

Calibration curves for the most frequently used detectors are on Fig 1 and Fig 2.

mailto:[email protected]

2

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0 500 1000 1500 2000 2500 3000

Eff

icie

ncy [

-]

Energy [keV]

Ep-p2-fit Ep-p2-exp

Ep-p3-fit Ep-p3-exp

Ep-p4-fit Ep-p4-exp

Ep-p5-fit Ep-p5-exp

Ep-p6-fit Ep-p6-exp

Fig 1: Efficiency curves for Canberra detector (A), positions p2, p3, p4, p5, and p6. Peak

efficiency fit is in solid line, measured points are in marks.

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 500 1000 1500 2000 2500 3000

Eff

icie

ncy [

-]

Energy [keV]

Ep-p2-fit Ep-p2-exp

Ep-p3-fit Ep-p3-exp

Ep-p4-fit Ep-p4-exp

Ep-p5-fit Ep-p5-exp

Ep-p6-fit Ep-p6-exp

Fig 2: Efficiency curves for Ortec-old (B) detector, positions p2, p3, p4, p5, and p6. Peak

efficiency fit is in solid line, measured points are in marks.

3

0.0E+00

2.0E+09

4.0E+09

6.0E+09

8.0E+09

1.0E+10

02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00

Beam

inte

nsi

ty [

d/b

unch]

Time

Kvinta 2 GeV

Fig 3: The course of irradiation during 2 GeV deuteron run on Kvinta.

0.0E+00

1.0E+09

2.0E+09

3.0E+09

4.0E+09

5.0E+09

6.0E+09

7.0E+09

8.0E+09

9.0E+09

1.0E+10

10:38 12:36 14:34 16:32 18:31 20:29 22:26 0:24 2:24 4:25

Beam

inte

nsi

ty [

d/b

unch]

Time

Kvinta 4 GeV


4

0.0E+00

2.0E+09

4.0E+09

6.0E+09

8.0E+09

1.0E+10

1.2E+10

22:21 0:19 2:17 4:15 6:13 8:11 10:11 12:08 14:06 16:04 18:04 20:03

Beam

inte

nsi

ty [

d/b

unch]

Time

Gamma-3 2.33 GeV

Fig 5: The course of irradiation during 2.33 GeV deuteron run on Gamma-3.

0.0E+00

2.0E+09

4.0E+09

6.0E+09

8.0E+09

1.0E+10

1.2E+10

1.4E+10

1.6E+10

16:59 18:24 21:05 22:23 23:55 2:47 4:05 5:23 7:11 8:29 10:21

Beam

in

ten

sity

[d

/bu

nch

]

Time

Kvinta 6 GeV


5

Yield calculation Gamma-spectra were evaluated in the Deimos 32 code [2]. From the gauss-fit of the peaks we

got also the statistical uncertainty (no any other uncertainties were taken into account in

following evaluation). Total yield of 24

Na in the Al foil was determined according to the

equation (1) (all corrections were included, for details see [3]):

(1)

where:

– decay constant,

tirr – irradiation time,

treal – real measurement time,

tlive – live time of the detector,

t0 – cooling time.

To get beam intensity as precise as possible, various spectroscopic corrections shown in

equation (1) were applied.

Correction on beam intensity changes during irradiation (Ba)

As the beam intensity was changing during deuteron irradiations, the code from Dubna [1]

was used to calculate the correction. This code calculates a shapeless number according to the

equation (1), every bunch is taken as one interval.

N

i

itit

p

irr

t

a

pe

irr

eeiWit

t

eB

1

)()()1()(

)(

1

1

(2)

where:

tirr – the total irradiation time,

te (i) – time from the end of the irradiation interval till the end of the whole irradiation,

tp (i) – time of calculated irradiation interval,

W (i) – ratio between the number of protons in the interval and in the whole irradiation,

N – the total number of intervals,

– decay constant.

Correction for

Coincidences

Peak area

Dead time

correction

Self-absorption

correction

Decay during cooling

and measurement

Decay during

irradiation

Detector

efficiency

Beam instability

correction

)()(

)(

11)(

)( 0

irrreal t

irr

t

t

live

real

areagP

aabsp

yielde

t

e

e

t

t

CoiCCEI

BECSN

line –intensity

per decay Correction for

geometry change

ge

Square-emitter

correction

6

Tab 1: Beam instability correction factors for 24

Na.

isotope T1/2 [h] correction factor

Kvinta 2 GeV

24Na 14.959

0.959

Kvinta 4 GeV 0.921

Gamma-3 2.33 GeV 0.926

Kvinta 6 GeV 1.055

Correction on non-point like emitters (Carea)

HPGe detectors were calibrated with point-like laboratory etalons, so the calibration is in

close geometries valid only for point sources. Al samples could not be measured far enough

from the detector due to their low activity, so the correction on non-point like emitters has to

be developed. It is based on MCNPX simulation, in which is studied response of the detector

on point-like and non-point like emitter, see equation (3). Correction values in the case of

2.5x2.5x0.3 cm3 emitter are summarized in Tab 2. Correction was verified in multiple

experiments, for more details see [6].

int)(

)(

po

foilc

p

p

g

(3)

Tab 2: Correction factors on non-point like emitters, detector A and B.

det A det B

p2 0.957 0.963

p3 0.973 0.973

p4 0.982 0.984

p5 0.994 0.992

p6 0.995 0.996

Correction on self-absorption (Cabs)

Al foil has after the folding from 10x10 cm2 onto 2.5x2.5 cm

2 thickness approximately 3 mm,

so the self absorption of the 24

Na gamma photons could not be neglected. Correction was

calculated according to the equation (4), Quantity cm-1 used in the equation is the total mass

attenuation coefficient T [cm2/g] divided by density [g/cm

3]. Values of come from Handbook of

Nuclear Data for Neutron Activation Analysis [7]. Correction factor were 1.021 in the case of

1368 keV gamma line, respectively 1.015 in the case of 2754 keV gamma line.

DD

x

D

abse

D

dxeD

I

dxD

I

C

1

0

0

0

0

(4)

7

Correction on changed detector efficiency due to sample dimensions (Cg)

Correction on changed detector efficiency had to be used because of the sample position

during measurement. The 3 mm thick foil had its centre approximately 1 mm closer to the

detector than was the position, for which the calibration was done. Detector efficiencies were

taken for positions p2-p8 and a curve was put through them. Than the detector efficiency for

position 1 mm closer to the detector was calculated. Ratio of the new and original efficiency

is the searched correction (1.042 for 1368 keV, 1.039 for 2754 keV – it is approximately the

same for all geometries).

Beam intensity calculation The value of the integral deuteron flux can be calculated from the yield according to the

relation

A

yield

dNm

ASNN

(5)

where is:

Nyield – total amount of produced 24Na nuclei, A – molar weight,

- cross-section, m – weight of the foil,

S – area of the foil,

NA – Avogadro‟s number.

Unfortunately, there are only three experimental cross-section values for 27

Al(d,3p2n)24

Na

reaction in GeV energy range. One value is from Dr. Bainaigs (15.25 ± 1.5 mbarn at 2330

MeV) [4] and two are from Dr. Kozma (14.1 ± 1.3 mbarn at 6000 MeV and 14.7 ± 1.2 mbarn

at 7300 MeV) [5], see Fig 7.

8

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

1 10 100 1000 10000

Cro

ss-s

ecti

on [

barn

]

Deuteron energy [MeV]

27Al(d,3p2n)24Na

2.33 GeV - 15.25 mbarn

2 GeV - 15.43 mbarn

6 GeV - 14.1 mbarn

4 GeV - 14.49 mbarn

Fig 7: Cross-section of 27

Al(d,3p2n)24

Na reaction – experimental data and fit of the points.

We made a linear fit between these three points and calculated the cross-section value for the

two energies between the points from database, we get a value 15.43 mbarn for 2 GeV and

value 14.49 mbarn for 4 GeV (error is about 10%).

From the yields gained for each beam energy in different measurements of the gamma line

1368 and 2754 keV a weighted average was done. χ2 was calculated and uncertainty of the

weighted average was enlarged where necessary. Results are summarized in the Fig 8 - Fig

11.

9

1.50E+13

1.55E+13

1.60E+13

1.65E+13

1.70E+13

1.75E+13

1.80E+13

1.85E+13

1.90E+13

0 1 2 3 4 5 6 7 8 9

Beam

inte

nsi

ty [

-]

Number of measurement [-]

Fig 8: Experimental points and weighted average for 24

Na (first half of the points belongs to

the gamma-line 1368 keV, second part is 2754 keV gamma line) in Al beam intensity monitor

– Kvinta 2 GeV.

1.32E+13

1.36E+13

1.40E+13

1.44E+13

1.48E+13

1.52E+13

1.56E+13

0 5 10 15

Beam

inte

nsi

ty [

-]

Number of measurement [-] Fig 9: Experimental points and weighted average for

24Na (first half of the points belongs to


– Kvinta 4 GeV.

10

1.75E+13

1.80E+13

1.85E+13

1.90E+13

1.95E+13

2.00E+13

2.05E+13

0 2 4 6 8 10 12 14

Bea

m inte

nsi

ty [

-]

Number of measurement [-] Fig 10: Experimental points and weighted average for

24Na (first half of the points belongs to


– Gamma-3 2.33 GeV.

1.84E+13

1.86E+13

1.88E+13

1.90E+13

1.92E+13

1.94E+13

1.96E+13

1.98E+13

2.00E+13

0 1 2 3 4 5

Beam

in

ten

sity

[-]

Number of measurement [-]

Fig 11: Experimental points and weighted average for 24

Na (first half of the points belongs to


– Kvinta 6 GeV.

11

Our results were compared with the results of other beam intensity measurements, see Tab 3

and Fig 12 - Fig 14. Our uncertainty is done only by the uncertainty gained from DEIMOS32

and weighted average analysis (pure statistical uncertainties) and is around 1 %. Other

uncertainties that should be included come from detector calibration (approximately 3 %),

corrections (approx 1%) and reaction cross-section (10 %, more at the energies with fitted

cross-section value). These uncertainties are the same for all (but it is now not clear whether

and which of them are included).

Tab 3: Comparison of intensities of deuteron beams for Kvinta and Gamma-3 runs.

Wagner Potapenko Voronko Hilmanovic Volkov Baldin

Kvinta 2 GeV (1.685±0.020)·1013

(1.35±0.19)·1013

(1.40±0.10)·1013

1.54·1013

- 1.65·1013

Kvinta 4 GeV (1.412±0.007)·1013

(1.90±0.7)·1013

(1.40±0.10)·1013

1.50·1013

1.8·1013

1.50·1013

Gamma-3

2.33 GeV (1.879±0.009)·1013

- - - - -

Kvinta 6 GeV (1.938±0.019)·1013

(1.91±0.29)·1013

(1.7±0.12)·1013

2.12·1013

2.55·1013

2.25·1013

1

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

Potapenko Voronko Hilmanovic Wagner

Beam

in

ten

sity

[1

01

3d

eu

tero

ns] Kvinta 2 GeV

Fig 12: Comparison of the results of beam intensity measurement by activation method,

2 GeV deuterons on Kvinta.

12

1

1.2

1.4

1.6

1.8

2

2.2

2.4

2.6

2.8


Beam

inte

nsi

ty [

10

13

deute

rons]

Kvinta 4 GeV



1.4

1.5

1.6

1.7

1.8

1.9

2

2.1

2.2

2.3


Beam

inte

nsi

ty [

10

13

deute

rons]

Kvinta 6 GeV



13

Beam position and shape For the beam position and shape, Cu foil was used. Foil was made of natural copper of

standard laboratory purity; we have no data about possible impurities. Thus, for further

evaluation only isotopes undoubtedly produced in the Cu(d,x) reactions were used.

The bigger one foils, 8x8x0.0128 cm3, were placed directly in front of the targets, on the

plane used also by Dr. Potapenko. Alignment of these foils were with the target axis, no target

rotation was taken into account (3° initial shift of the Kvinta target causes some basic “beam

shift”). These foils were after the irradiation cut into 16 pieces 2x2x0.0128 cm3 big and every

piece was measured separately. To get more precise results on beam position, we cut the most

hit foils into four pieces (1x1x0.0128 cm3) and measured them once again. There are no cross-

sections for the Cu(d,x) reactions, we could only calculate the yields of produced isotopes,

according to the equation 2.

Following isotopes were observed: 58

Co, 56

Co, 48

Cr, 52

Mn, 48

Sc, 44m

Sc, 57

Ni, 48

V, 47

Sc, 55

Co, 48

Cr, 43

K, and 44

Sc. Totally 19 lines were used for the final evaluation. Above mentioned

isotopes were observed mostly only in those four most active foils, in other foils they were not

detected or were on the level of detection limit (this represents relative production between 1-

6 % in non-hit foils). No one of these isotopes was visible in all foils and with similar

activities; this leads us to the presumption that all the isotopes we used were produced by the

deuterons from the beam and not by back-scattered neutrons from the target.

2 GeV deuterons on Kvinta

0.000.01 0.12

0.05

0.000.04

0.99

0.33

0.000.02

0.56

0.20

0.000.00

0.030.02

Beam profile in front of the target - big monitors

left

rightcentre

centre

top

down

Fig 15: Normalized activities in the cut Cu foil placed in front of the target, 2 GeV deuterons

on Kvinta.

beam shift in X: 1.2 cm (to the right in the beam direction)

FWHM: 2 cm

beam shift in Y: - 0.5 cm (down)

FWHM: 2.8 cm

14


0.00

0.00

0.06

0.02

0.00

0.03

0.99

0.23

0.01

0.02 0.21

0.05

0.00

0.00

0.00

0.00

Beam profile in front of the target - big monitors

left

right

centre

centre

top

down


on Kvinta.

beam shift in X: 1.2 cm (to the right in the beam direction)

FWHM: 2.2 cm

beam shift in X from cut foils 11 and 12 (most active one): 1.6 cm

FWHM: 1.5 cm

beam shift in Y: -0.7 cm (down)

FWHM: 2.3 cm

Foils 11 and 12 were cut onto a pieces 1x1 cm2 and measured separately. Results of its

analysis are in following Fig 17.

0.09

0.31

0.14

0.01

0.17

0.99

0.23

0.01

Beam profile from small monitors

foil 11 foil 12

11-1 11-2 12-1 12-2

11-3 11-4 12-3 12-4

3 4

7 8

13 14 15 16

1 2

5 6

9 10

Fig 17: Normalized activities on cut foils number 11 and 12 (most active foils), 1 GeV/A

deuterons on Kvinta.

15

2.33 GeV deuterons on Gamma-3

0.02 0.13 0.13 0.02

0.05

0.990.53

0.06

0.02 0.18 0.19 0.03

0.01 0.02 0.02 0.01

left rightcentre

centre

top

down

Fig 18: Normalized activities in the cut Cu foil placed in front of the target, 2.33 GeV

deuteron experiment on Gamma-3.

beam shift in X: -0.3 cm (to the left in the beam direction)

FWHM: 2.3 cm


FWHM: 2.4 cm


0.020.01

0.100.07

0.010.05

0.98

0.80

0.000.04

0.860.87

0.000.01

0.080.09

left

rightcentre

centre

top

down


on Kvinta.

16

beam shift in X: 2 cm (to the right in the beam direction)

FWHM: 3.9 cm


FWHM: 3.1 cm

Our values are also within uncertainties in the good agreement with A. Potapenko results (but

they are less precise thanks to used method of measurement).

Beam alignment with the target axis One Cu foil was placed behind the setup to verify beam direction and its alignment with the

target. Foil was 9x9x0.0128 cm3 big and made of the same copper as the front foil. After the

irradiation it was cut onto 9 pieces 3x3x0.0128 cm3 big and each part was measured

separately. Same isotopes as in the front foil were detected, the evaluation is not completely

finished. Results are summarized in the following Fig 20.

0.06

0.12

0.01

0.070.05

0.04

0.03 0.05

0.00

Behind target

centre

top

down

left

right

centre

0.28 0.33

0.16

0.66 0.87

0.25

0.21 0.200.17

Behind target

centre

top

down

leftrightcentre

Fig 20: Beam position behind the target during 2 GeV (left) and 4 GeV (right) deuteron

irradiation on Kvinta target.

Conclusion By the means of activation analysis we measured the intensity, position and shape of the

deuteron beam during the 2, 4 and 6 GeV Kvinta and 2.33 GeV Gamma-3 deuteron

irradiations performed in March 2011. With the Al foil placed into the deuteron beam we

measured beam intensity, out values are in good agreement with the results of other groups.

Cu foil was used for position and shape measurements. The beam was more or less in the

centre of the target in all four irradiations; our values are in a good agreement with the results

of other groups. Evaluation of the beam alignment measurements are not yet finished.

Presented data are almost a final one, but some long time measurements and further analysis

are planned.

Literature [1] Kumawat H.: Development of Cascade Program and its Applications to Modeling

Transport of Particles in Many Component Systems, Dissertation Thesis, JINR Dubna (2004).

17

[2] Frána J.: Program DEIMOS32 for Gamma-Ray Spectra Evaluation, J. Rad. Nucl. Chem.,

V. 257, No. 3 P. (2003) 583-587.

[3] Majerle M.: Monte Carlo Methods in Spallation Experiments, Dissertation thesis, FNSPE

CTU Prague, 2009 (http://ojs.ujf.cas.cz/~wagner/transmutace/diplomky/mitjathesis.pdf)

[4] Banaigs J. et al.: Determination De L„Intensite D„Un Faisceau De Deutons Extrait D‟Un

Synchrotron Et Mesure Des Sections Efficaces Des Reactions C-12(D,P2N)C-11 Et Al-

27(D,3P2N)Na-24 a 2.33 GeV, Nuclear Instruments and Methods in Physics Research 95

(1971) 307-311

[5] Kozma P. and Yanovski V. V.: Application of BaF2 scintillator to off-line gamma ray

spectroscopy, Czech Journal of Physics, 40 (1990) 393-397

[6] Svoboda O.: Experimental Study of Neutron Production and Transport for ADTT, PhD.

Thesis, ČVUT-FJFI 2011,

http://ojs.ujf.cas.cz/~wagner/transmutace/diplomky/PHD_Svoboda.pdf

[7] Hnatowicz V.: Handbook of Nuclear Data for Neutron Activation Analysis, vol. 1,

Czechoslovak Atomic Energy Commission – Nuclear Information Centre, 57-805/86, Prague

(1986)

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