Results of transmission measurements for 40Ca at GELINA.
Date: 2015-12-22
Institutions: Institute for Reference Materials and Measurements
Subjects: data processing, metrology, nuclear energy, nuclear research, nuclear safety, research report

² 

Results of transmission measurements  
for 40Ca at GELINA 

Carlos Paradela 
Klaus Guber 
Gery Alaerts 
Jan Heyse 
Stefan Kopecky 
Peter Schillebeeckx 
Danny Vendelbo 
Ruud Wynants 

2 0 1 5  

Report EUR 27559 EN

 
 
 
 
² 

European Commission 

Joint Research Centre 
Institute for Reference Materials and Measurements 

Contact information 

Peter Schillebeeckx 
Address: Joint Research Centre, Retieseweg 111, 2440 Geel, Belgium 
E-mail: peter.schillebeeckx@ec.europa.eu 
Tel.: +32 (0)14 571 475 

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https://ec.europa.eu/jrc 

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All images © European Union 2015 

JRC98273 

EUR 27559 EN 

ISBN 978-92-79-53456-0 

ISSN 1831-9424 

doi:10.2787/098334 

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© European Union, 2015 

Reproduction is authorised provided the source is acknowledged. 

Abstract 
Transmission  measurements  have  been  performed  at  the  neutron  time-of-flight  facility  GELINA  to  determine  the  total  cross  section  for 
neutron induced reactions on 40Ca. The experimental details, i.e. measurement conditions, sample characteristics, measurement procedures 
and experimental uncertainty components, together with the data reduction procedures are described. The experimental results including the 
full covariance information, based on the AGS-formalism, are reported following the latest recommendations of the International Nuclear 
Data Committee. This includes the information that is required to derive nuclear reaction model parameters together with their covariances 
by a least squares adjustment to experimental data.  

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
RESULTS OF TRANSMISSION MEASUREMENTS  

FOR 40CA AT GELINA 

C. Paradela1, K. Guber2, G. Alaerts1, J. Heyse1, S. Kopecky1,  
P. Schillebeeckx1, D. Vendelbo and R. Wynants1 

1European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 
Retieseweg 111, B - 2440 Geel, Belgium 

2Oak Ridge National Laboratory,  
BG-1784 Oak Ridge, United States 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Executive summary 

Transmission measurements have been performed at a 50 transmission station of the neutron time-of-flight 
facility  GELINA  to  determine  the  total  cross  section  for  neutron  induced  reactions  on  40Ca.  These 
measurements  are  part  of  a  collaboration  of  the  Joint  Research  Centre  and  the  Oak  Ridge  National 
Laboratory  (US)  to  improve  nuclear  data  for  nuclear  criticality  safety  applications.  They  have  been 
supported by the EUFRAT project.  

This report provides the experimental details required to submit the data to the EXFOR data library which is 
maintained  by  the  Nuclear  Data  Section  of  the  IAEA  and  the  Nuclear  Energy  Agency  of  the  OECD.  The 
experimental  details,  i.e.  measurement  conditions,  sample  characteristics,  measurement  procedures  and 
experimental  uncertainty  components,  together  with  the  data  reduction  procedures  are  described.  The 
experimental results including the  full covariance  information, based on the  AGS-formalism, are reported 
following  the  latest  recommendations  of  the  International  Nuclear  Data  Committee.  This  includes  the 
information that is required to derive nuclear reaction model parameters together with their covariances by 
a least squares adjustment to experimental data. 

 
 
 
 
 
 
Contents 

1. 

Introduction  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . .  .  .  .  .  . .  .  .  .  .  .  .  . .  .  .  .  .  .  . 

2.  Experimental conditions   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 

3.  Data reduction .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . . 

4.  Results   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 

References   .  .  .  .  .  .  .  .  .  .  .  .  .  .  . .  .  .  .  .  . .  .  .  .  .  .  .  . .  .  .  .  .  .  .  .  . . 

Appendix A  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . .  .  .  .  .  . .  .  .  .  .  .  .  . .  .  .  .  .  .  .  .  .  . 

2 

2 

4 

6 

7 

9 

1 

 
 
 
 
 
 
1. Introduction 

To  study  the  resonance  structure  of  neutron  induced  reaction  cross  sections,  neutron  spectroscopic 
measurements are required which determine with a high accuracy the reaction cross sections and energy of 
the  neutron  that  interacts  with  the  material  under  investigation.  To  cover  a  broad  energy  range  such 
measurements  are  best  carried  out  with  a  pulsed  white  neutron  source,  which  is  optimized  for  time-of-
flight (TOF) measurements [1].  

The TOF facility GELINA [2] has been designed and built for high-resolution cross section measurements in 
the resolved (RRR) and unresolved (URR) resonance region. It is a multi-user TOF facility, providing a white 
neutron  source  with  a  neutron  energy  range  from  10  meV  to  20  MeV.  Up  to  10  experiments  can  be 
performed  simultaneously  at  measurement  stations  located  between  10  m  to  400  m  from  the  neutron 
production target. The electron linear accelerator provides a pulsed electron beam with a maximum energy 
of  150  MeV,  an  average  current  of  about  55  m A  and  a  repetition  rate  ranging  from  50  Hz  to  800  Hz.  A 
compression magnet reduces the width of the electron pulses to less than 2 ns [3]. The electron beam hits a 
mercury-cooled  uranium  target  producing  Bremsstrahlung  and  subsequently  neutrons  via  photonuclear 
reactions  [4].  Two  water-filled  beryllium  containers  mounted  above  and  below  the  neutron  production 
target  are  used  to  moderate  the  neutrons.  By  applying  different  neutron  beam  collimation  conditions, 
experiments  can  use  either  a  fast  or  a  thermalized  neutron  spectrum.    The  neutron  production  rate  is 
constantly monitored by BF3 proportional counters which are mounted in the ceiling of the target hall. The 
output of the monitors is used to normalize the time-of-flight spectra to the same neutron intensity.  The 
measurement stations are equipped with air conditioning to reduce electronic drifts in the detection chains 
due to temperature changes.  

In this report results of transmission measurements carried out at GELINA with a natural calcium sample are 
described.  To  reduce  bias  effects  due  to  e.g.  dead  time  and  background,  the  measurement  and  data 
reduction procedures recommended in Ref. [1] have been followed. The main objective of this report is to 
provide the information that is required to evaluate the total cross section for 40Ca in the resonance region 
and  to  extract  nuclear  reaction  model  parameters  in  a  least  squares  adjustment  to  the  data  [1].  In  the 
description of the data the recommendations of the International Nuclear Data Committee (INDC), resulting 
from a consultant's meeting organized by the Nuclear Data Section of the IAEA, are followed [5]. 

These  measurements  are  part  of  a  collaboration  between  the  Joint  Research  Centre  and  the  Oak  Ridge 
National  Laboratory  (US)  to  improve  nuclear  data  evaluations  for  neutron  induced  reactions  that  are 
important for nuclear criticality safety. Calcium is a concrete constituent and it is very frequently found in 
combination  with  uranium,  either  for  the  construction  of  nuclear  power  plants  or  in  storage  facilities  for 
nuclear  waste.  Liquid  radioactive  waste  is  often  solidified  by  mixing  it  with  concrete.  Calcium  has  strong 
neutron-absorbing  properties  that  can  affect  the  reactivity  of  systems  with  fissionable  materials.  The 
evaluated data for calcium found in the nuclear data libraries do not perform well in criticality calculations. 
In addition, a consistent set of covariance data is needed in support of sensitivity and uncertainty analyses.  

2. Experimental conditions 

The transmission experiments were performed at the 50 m measurement station of flight path 4 with the 
accelerator operating at 800 Hz. The flight path forms an angle of 9o with the direction normal to the facet 
of the moderator viewing the flight path. The moderated neutron spectrum was used. A shadow bar made 
of Cu and Pb was placed close to the uranium target to reduce the intensity of the g -ray flash and the fast 
neutron  component.  The  sample  and  detector  were  placed  in  a  acclimatised  room  to  keep  them  at  a 
constant  temperature  of  22  oC.  A  schematic  view  of  the  experimental  set-up  is  shown  in  Fig.  1.  The 
experimental  conditions  for  each  experiment,  including  the  monitor  counts  and  type  of  background  and 
overlap filters used in the experiment, are specified in Appendix A based on a template provided in Ref. [5]. 

The neutrons scattered from the moderators are collimated into evacuated pipes of 50 cm diameter with 
annular collimators. A combination of Li-carbonate plus resin, Pb and Cu-collimators was used to reduce the 
neutron  beam  to  a  diameter  of  about  45  mm  at  the  sample  position.  The  sample  was  placed  in  an 
automatic  sample  changer  at  a  distance  of  approximately  24  m  from  the  neutron  source.  A  10B  overlap 

2 

 
 
 
 
 
 
filter,  with an areal density of 8 10-3 at/b, was placed to absorb slow neutrons  from previous bursts. The 
impact of the  g -ray flash was reduced by a 16 mm thick Pb filter.  A set of Na, Co and W black resonance 
filters  were  mounted  in  an  automatic  filter  changer  close  to  the  sample  position  to  determine  the 
background with the black resonance technique [1].  

The  neutron  beam  passing  through  the  sample  and  filters  was  further  collimated  and  detected  by  a  6.35 
mm  thick  and  152.4  mm  diameter  NE912  Li-glass  scintillator.  The  scintillator  was  connected  through  a 
boron-free quartz window to a 127 mm EMI 9823 KQB photomultiplier (PMT), which was placed outside the 
neutron beam and perpendicularly to its axis. The detector was placed at a distance of 49.34 m from the 
facet of the moderator viewing the flight path. The diameter of the neutron beam at the detector position 
was about 85 mm.  

Figure 1 Schematic representation of the transmission set-up at the 50 m transmission station of GELINA. 

The output signals of the PMT were connected to conventional analog electronics. The anode pulse of the 
PMT was fed into a constant fraction discriminator to create a fast logic signal which defines the time the 
neutron  has  been  detected.  The  signal  of  the  9th  dynode  was  shaped  by  a  spectroscopic  amplifier  to 
determine  the  energy  deposited  by  the  6Li(n,t)a
  reaction  in  the  detector.  A  module  was  included  to 
produce a fixed dead time in the whole electronics chain directly after the detection of an event. This dead 
time  td  =  3305  ns  was  continuously  monitored  by  recording  the  time  interval  between  successive  pulses. 
The time-of-flight (TOF) of the detected neutron was determined by the time difference between the stop 
signal (Ts) derived from the anode pulse of the PMT and the start signal (T0), given at each electron burst. 
This time difference was measured with a multi-hit fast time coder with a 1 ns time resolution. The TOF and 
pulse height of a detected event were recorded in list mode data using a multi-parameter data acquisition 
system developed at the EC-JRC-IRMM [6]. Each measurement was subdivided in different cycles of about 
900'' each. 

Table 1. Characteristics of the samples used for the transmission measurements performed at GELINA. The 
uncertainties  are  standard  uncertainties  at  1  standard  deviation.  To  calculate  the  areal  density  the 
Avogadro constant was taken as NA = 6.0221367 1023 mol-1 and the atomic mass for natCa as ma = 40.0780 g. 
The uncertainty on the areal density is dominated by the 0.2 % uncertainty on the area, which includes an 
uncertainty due to non-perfect circular shape of the samples. 

Sample ID 

Thickness 

Diameter 

Mass 

Areal density 

1 
2 
3 

12.55 mm 
15.35 mm 
20.22 mm 

60.00 mm 
59.95 mm 
59.98 mm 

54.438 g 
66.212 g 
85.627g 

2.893 (0.006) 10-2 at/b 
3.525 (0.007) 10-2 at/b 
4.554 (0.009) 10-2 at/b 

To  avoid  background  originating  from  oxygen  and  carbon  in  calcium  carbonate  samples,  metallic  calcium 
samples were chosen. Three metallic Ca discs were used to produce a sample with a thickness of ~
 5 cm and 
a  total  combined  mass  of  206.277  g.  The  characteristics  of  the  discs  are  given  in  Table  1.  They  were 
encapsulated  in  a  thin-walled  aluminium  container  to  prevent  reactions  with  air.  To  compensate  for  the 
effect of the  metallic can, data were taken with an Al empty container with similar characteristics as the 
sample container. 

3 

 
 
 
 
 
 
 
3. Data reduction 

The experimental transmission Texp as a function of the time-of-flight, denoted by tm, was obtained from the 
ratio of the counts of a sample-in measurement Cin and a sample-out measurement Cout, after subtraction of 
the background contributions Bin and Bout, respectively [1]: 

T
exp

t(

m

=
N)

C

t(C
min
t(

out

m

t(BK)
BK)

min
t(

out

)

m

   , 

)

(1) 

where tm denotes the measured time-of-flight. The TOF-spectra (Cin, Bin, Cout, Bout) in Eq. 1 were corrected 
for  losses  due  to  the  dead  time  in  the  detector  and  the  electronics  chain.  The  factor  K  is  introduced  to 
account for the uncertainty due to the background. 

The  dead  time  correction  was  based  on  the  formula  of  Moore  [7].  This  formula  accounts  for  possible 
variations  in  the  beam  intensity.  The  dead  time  correction  factors  as  a  function  of  time-of-flight  for  the 
sample-in and sample-out data are plotted in Fig.2. The maximum dead time correction for tm > 104 was less 
than  20%.  It  has  been  demonstrated  in  Refs.  [1,8]  that  bias  effects  resulting  from  such  corrections  are 
negligible. Therefore, the uncertainties related to the dead time correction were not propagated. 

 Sample - in
 Sample - out

r
o

t
c
a

f

n
o
i
t
c
e
r
r
o
c
e
m

i
t

d
a
e
D

1.6

1.4

1.2

1.0

103

104
Time-of-flight / ns

105

106

Figure 2 Dead time correction factor as a function of time-of-flight for both the sample-in and sample-out 
measurements. 

All  spectra  were  normalized  to  the  same  TOF-bin  width  structure  and  neutron  beam  intensity.  The  latter 
was  derived  from  the  response  of  the  BF3  beam  monitors.  To  avoid  systematic  uncertainties  due  to  slow 
variations  of  both  the  beam  intensity  and  detector  efficiency  as  a  function  of  time,  data  were  taken  by 
alternating  sample-in  and  sample-out  measurements  in  cycles  of  about  900''  each.  Such  a  procedure 
reduces  the  uncertainty  on  the  normalization  due  to  the  beam  intensity  to  less  than  0.25  %  [1].  This 
uncertainty  was  evaluated  from  the  ratios  of  the  counts  in  the  6Li  transmission  detector  and  in  the  flux 
monitors. To account for this uncertainty the factor N = 1.0000 –

 0.0025 was introduced in Eq.1.  

The  background  as  a  function  of  TOF  was  determined  by  an  analytical  expression  applying  the  black 
resonance  technique.  The  factor  K  =  1.00  –
  0.03  in  Eq.  1  introduces  a  correlated  uncertainty  component 
accounting for systematic effects due to the background model. The background as a function of TOF was 
approximated by a sum of a constant and three exponentials [1]: 

t+

t(
m3

)

t
m1

+

t
m2

+

=
b)

+

0

0

m

t(B

   . 

eb
1

eb
3

eb
2

(2) 
where t 0 is related to the operating frequency of the accelerator, i.e. here t 0 = 1.25 ms for the accelerator 
operating  at  800  Hz.  The  time  independent  contribution  b0  is  very  small  and  can  be  estimated  from 
measurements when the accelerator is not in operation. The first exponential accounts for the contribution 
due to the detection of 2.2 MeV  g -rays resulting from neutron capture in hydrogen that is present in the 
moderator. The second exponential originates predominantly from neutrons scattered inside the detector 
station.  The  last  component  is  due  to  the  detection  of  overlap  neutrons.  The  free  parameters  in  the 
analytical expression (b0, b1, b2, l 1, l 2 and l 3) were determined by a least squares fit to saturated resonance 

4 

 
 
 
-
-
 
 
 
 
l
-
l
-
l
-
 
 
 
 
 
dips  observed  in  the  TOF-spectra  resulting  from  measurements  with  black  resonance  filters.  The  time 
dependence of the background was derived from dedicated measurements with S, Na, Cu, Co, W, Au and 
Ag  black  resonance  filters  in  the  beam.  During  the  regular  sample-in  and  sample-out  runs  Na,  Co  and  W 
fixed filters were kept in the beam to continuously monitor the background at 2.85 keV, 132 eV and 20 eV, 
respectively, and to account for the dependence of the background level on the presence of the sample [1]. 
Examples  of  dead  time  corrected  TOF-spectra  together  with  the  background  contributions  are  shown  in 
Figs. 3 and 4, respectively. The parameters of the analytical expression in Eq. 2 are given in Table 2. 

t

=

The  time-of-flight  tm  of  a  neutron  creating  a  signal  in  the  neutron  detector  was  determined  by  the  time 
difference between the start signal (T0) and the stop signal (Ts): 
t

(2) 
with t0 a time-offset which was determined by a measurement of the g -ray flash. The flight path distance L = 
49.345 (0.004) m, i.e. the distance between the centre of the moderator and the front face of the detector, 
was  derived  previously  from  result  of  transmission  measurements  on  238U  using  the  6.673  –
  0.001  eV 
resonance of 238U+n as a reference [9]. 

)T
0

   , 

T(
s

+

m

0

Table  2  Parameters  for  the  analytical  expressions  of  the  background  correction  for  the  sample-in  and 
sample-out measurements. 
b0/10-8 ns 
1.25 
1.41 

l 1/10-5 ns-1 
2.94 
2.94 

l 3/10-6 ns-1 
2.70 
2.70 

l 2/10-6 ns-1 
1.35 
1.35 

b3/10-7 ns 
5.47 
7.41 

b1/10-7 ns 
3.58 
4.61 

b2/10-7 ns 
0.209 
0.275 

ID 
Cin 
Cout 

  Cd
  B

d

  b0
  b
1
  b
2
  b
3

 e- l
 e- l
 e- l

1t

2t

3(t+t0)

10-4

10-6

)
s
n
/
1
(

/

e
s
n
o
p
s
e
R

10-8

103

104
Time-of-flight / ns

105

106

Figure 3 Time-of-flight spectrum without sample in the beam is compared with the total background and its 
components. 

  Cin
  Bin

10-4

10-6

)
s
n
/
1
(

/
e
s
n
o
p
s
e
R

  b

0

1

 e- l
  b
  b2 e- l
 e- l
  b

3

1t

2t

3(t+t

)
0

10-8

103

104
Time-of-flight / ns

105

106

Figure  4  Time-of-flight  spectrum  with  the  dummy  sample  in  the  beam  is  compared  with  the  total 
background and its components. 

5 

 
 
 
 
-
 
 
 
 
 
 
 
 
 
 
 
 
4. Results 

The  AGS  (Analysis  Of  Geel  Spectra)  code  [10],  developed  at  the  EC-JRC-IRMM,  was  used  to  derive  the 
experimental  transmission.  The  code  is  based  on  a  compact  formalism  to  propagate  all  uncertainties 
starting from uncorrelated uncertainties due to counting statistics. It stores the full covariance information 
after each operation in a concise, vectorized way. The AGS formalism results in a substantial reduction of 
data  storage  volume  and  provides  a  convenient  structure  to  verify  the  various  sources  of  uncertainties 
through each step of the data reduction process. The concept is recommended by the INDC [5] to prepare 
the experimental observables, including their full covariance information, for storage into the EXFOR data 
library [11,12]. The transmission for the measurements with the Ca sample and the dummy sample are both 
delivered to the EXFOR data base. 

The experimental transmission resulting from the measurements on the 50 mm thick natCa sample is shown 
in Fig. 5. The format in which the numerical data is stored in the EXFOR data library is illustrated in Table 3. 
Fig. 5 compares the experimental transmission resulting from the experiments described in this work and 
the  theoretical  transmission  using  the  resonance  parameters  recommended  in  the  JEFF-3.2  library.  This 
figure shows obvious inconsistencies between the present data and the recommended parameters: e.g. the 
interference profile in the 20 keV region shows that the parity assignment of the 20 keV resonance as an s-
wave is not correct; below 50 keV the contribution of bound states and/or scattering radius is too large; and 
most of the resonance energies and neutron widths require an adjustment. Hence, a new evaluation of the 
parameters is required.  

The  data  in  Table  3  include  the  full  covariance  information  based  on  the  AGS  concept.  Applying  the  AGS 
concept described in Ref. 10 the covariance matrix V of the experimental transmission can be calculated by: 

=
UV
u

h+

)(S)(S

T

   , 

(4) 

where Uu is a diagonal matrix containing the contribution of all uncorrelated uncertainty components. The 
matrix S contains the contribution of the components h
 = {N,K} creating correlated components. The total 
uncertainty  and  the  uncertainty  due  to  uncorrelated  components  are  reported,  together  with  the 
contributions due to the normalization to the neutron beam intensity (N) and background model (K).  

It  is  recommended  that  only the  data  between  200  eV  and  2.5  keV  and  between  3  keV  and  150  keV  are 
used for a resonance shape analysis. The experimental details, which are required to perform an analysis of 
the data in terms of reaction model parameters, are summarized in Appendix A.  

1.0

0.8

0.6

0.4

0.2

20
0
-20

  T

  T

exp

REFIT

i

i

n
o
s
s
m
s
n
a
r
T

l

s
a
u
d
s
e
R

i

0

50000

100000

150000

200000

Neutron energy / eV

Figure  5  Comparison  of  the  experimental  transmission  and  the  transmission  derived  from  the  resonance 
parameters in the JEFF-3.2 library. For the calculations the REFIT code [13] was used. 

6 

 
 
 
 
 
h
 
 
 
 
 
 
 
Table 3 Illustration of the data structure submitted to the EXFOR data library. The first column is the energy 
that is derived from the measured time-of-flight based on the relativistic equation and a flight path length 
L=  49.345  m.  The  second  and  third  column  provide  the  time-of-flight  boundaries.  The  final  experimental 
transmission together with the total uncertainty are given in column 4 and 5. The information to derive the 
full  covariance  matrix  based  on  the  AGS-formalism  (Eq.  4)  is  given  in  columns  6,  7  and  8:  the  diagonal 
elements due to the uncorrelated uncertainty components are in column 6. The data required to account 
for the correlated components S{K,N} are given in columns 7 and 8. A high number of significant digits is given 
to ensure that the resulting covariance matrix can be inverted.  

E/ eV 

tl / ns 

th / ns 

Texp 

198837.4 
… 
8.180 
8.178 
… 
1.28 

8000 
… 
1247232 
1247360 
… 
3149760 

8002 
… 
1247360 
1247488 
… 
3149824 

0.892 
… 
0.852 
0 
… 
0 

(cid:1)(cid:2) 

0.0103 
… 
0.1313 
0 
… 
0 

(cid:1)(cid:3) 
0.0101 
… 
0.1273 
0 
… 
0 

AGS 

SK 
-0.0000288 
… 
-0.0319624 
0 
… 
0 

SN 
0.00223 
… 
0.00213 
0 
… 
0 

References 

[1]  P.  Schillebeeckx,  B.  Becker,  Y.  Danon,  K.  Guber,  H.  Harada,  J.  Heyse,  A.R.  Junghans,  S.  Kopecky,  C. 
Massimi, M.C. Moxon, N. Otuka, I. Sirakov and K. Volev, "Determination of resonance parameters and 
their  covariances  from  neutron  induced  reaction  cross  section  data",  Nucl.  Data  Sheets  113  (2012) 
3054 – 3100. 

[2]  W.  Mondelaers  and  P.  Schillebeeckx,  "GELINA,  a  neutron  time-of-flight  facility  for  neutron  data 

measurements", Notiziario Neutroni e Luce di Sincrotrone 11 (2006) 19 – 25. 

[3]  D.  Tronc,  J.M.  Salomé  and  K.H.  Böckhoff,  "A  new  pulse  compression  system  for  intense  relativistic 

electron beams", Nucl. Instr. Meth.  228 (1985) 217 – 227. 

[4]  A.  Bensussan  and  J.M.  Salomé,  "GELINA:  A  modern  accelerator  for  high  resolution  neutron  time  of 

flight experiments", Nucl. Instr. Meth. 155 (1978) 11 – 23. 

[5]  F. Gunsing, P. Schillebeeeckx and V. Semkova, "Summary Report of the Consultants' Meeting on EXFOR 
Data in Resonance Region and Spectrometer Response Function", IAEA Headquarters, Vienna, Austria, 
8  –  10  October  2013,  INDC(NDS)-0647  (2013),  https://www-nds.iaea.org/index-meeting-crp/CM-RF-
2013/. 
J.  Gonzalez,  C.  Bastian,  S.  de  Jonge  and  K.  Hofmans,  "Modular  Multi-Parameter  Multiplexer  MMPM. 
Hardware description and user guide", Internal Report GE/R/INF/06/97, IRMM, Geel. 

[6] 

[7]  M.S.  Moore,  "Rate  dependence  of  counting  losses  in  neutron  time-of-flight  measurements",  Nucl. 

Instr. Meth. 169 (1980) 245 – 247.  

[8]  L.C.  Mihailescu,  A.  Borella,  C.  Massimi  and  P.  Schillebeeckx,  "Investigations  for  the  use  of  the  fast 
digitizers with C6D6 detectors for radiative capture measurements at GELINA", Nucl. Instr. Meth. A 600 
(2009) 453 – 459. 

[9]  H.  Derrien,  L.C.  Leal,  N.M.  Larson  and  A.  Courcelle,  "Neutron  Resonance  Parameters  and  Calculated 
Cross Sections from Reich-Moore Analysis of Experimental Data in the Neutron Energy Range from 0 to 
20 keV”, ORNL/TM-2005/241, Oak Ridge National Laboratory, (2005). 

[10]  B. Becker, C. Bastian, F. Emiliani, F. Gunsing, J. Heyse, K. Kauwenberghs, S. Kopecky, C. Lampoudis, C. 
Massimi,  N.  Otuka,  P.  Schillebeeckx  and  I.  Sirakov,  “Data  reduction  and  uncertainty  propagation  of 
time-of-flight spectra with AGS”, J. of Instrumentation 7 (2012) P11002 – 19. 

[11]  N.  Otuka,  A.  Borella,  S.  Kopecky,  C.  Lampoudis  and  P.  Schillebeeckx,  "Database  for  time-of-flight 

spectra with their covariances", J. Korean Phys. Soc. 59 (2011) 1314 – 1317.  

[12]  N. Otuka, S. Dunaeva, E. Dupont, O. Schwerer and A. Blokhin, "The role of the nuclear reaction data 
centres in experimental nuclear data knowledge sharing", J. of the Korean Phys. Soc. 59 (2011) 1292 – 
1297. 

[13]  M.C. Moxon and J.B. Brisland, Technical Report AEA-INTEC-0630, AEA Technology (1991). 

7 

 
 
 
 
 
 
 
 
 
 
8 

 
 
 
 
Appendix A 
SUMMARY OF EXPERIMENTAL DETAILS 

A. EXPERIMENT DESCRIPTION 
 Main Reference 

Facility 

Neutron production 

GELINA 

[1,2] 

[3] 

Neutron production beam 
Nominal average beam energy 
Nominal average beam current 
Repetition rate (pulses per second) 
Pulse width 
Primary neutron production target 
Target nominal neutron production intensity 

Electron 
100 MeV 
55 m A 
800 Hz 
1 ns 
Mercury cooled depleted uranium 
3.4 1013

 s-1

Moderator 

Primary neutron source position in moderator 
Moderator material 
Moderator dimensions (internal) 
Mass 
Temperature (K) 
Moderator-room decoupler (Cd, B, …) 

Above and below uranium target 
2 water filled Be-containers around U-target 
2 x (14.6 cm x 21 cm x 3.9 cm) 
H2O 
Room temperature 
None 

Other experimental details 

Measurement type 
Method (total energy, total absorption, …) 
Flight Path length (m) 
 (moderator – detector: face to face distance) 
Flight path direction   

Neutron beam dimensions at sample position 
Overlap suppression 
Other fixed beam filters 

Transmission 
Good transmission geometry 
L = 49.345 m   

[4] 

9o  with  respect  to  normal  of  the  moderator 
face viewing the flight path 
45 mm in diameter 
10B overlap filter (0.008 at/b) 
Na, Co, W, Pb (16 mm) 

Detector 

Type 
Material 
Surface Dimensions 
Thickness (mm) 
Detector(s) position relative to neutron beam 

Scintillator (NE912) 
Li-glass 
152.4 mm in diameter 
6.35 mm in thick 
In the beam 

Sample 

Type (metal, powder, liquid, crystal) 
Chemical composition 
Areal number density (at/b) 
Isotopic composition (at%) 

Temperature 
Sample mass (g) 
Geometrical shape (cylinder, sphere, …) 
Nominal surface dimension  
Nominal thickness (mm) 
Containment description 
Additional comment 

9 

Metal 

 0.02) x 10-2 

natCa: (10.97 –
40Ca  (96.941),  42Ca  (0.647),  43Ca  (0.135),  44Ca 
(2.086), 46Ca (0.004), 48Ca (0.187) 
22 oC 
(206.277 –
Cylinder 
60 mm diameter (see table 1) 
48 mm (see table 1) 
Al canning 
Stack of 3 discs 

 0.002) g (see table 1) 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Data Reduction Procedure 

Dead time correction 
Back ground subtraction 
Flux determination (reference reaction, …) 
Normalization  
Detector efficiency  
Self-shielding 
Time-of-flight binning 

[4,5] 

 0.0025 

Done (< factor 1.2) 
Black resonance technique 
- 
1.000 –
- 
- 
Zone length  
6240 
4096 
4096 
4096 
4096 
4096 
6144 
28672 

bin width 
2 ns 
4 ns 
8 ns 
16 ns 
32 ns 
64 ns 
128 ns 
64 ns 

Response function 

Initial pulse 
Target / moderator assembly 
Detector 

B. DATA FORMAT 

Normal distribution, FWHM = 2 ns 
Numerical distribution from MC simulations 
Analytical function defined in REFIT manual 

[6,7] 
[8] 

Colu
mn 
1 
2 
3 
4 
5 
6 
7 
8 

Content 

Unit 

Comment 

Energy 
TOFmin 
TOFmax 
Texp 
Total Uncertainty 
Uncorrelated uncertainty 
SN-vector 
SK-vector 

eV 
ns 
ns 

Relativistic relation using a fixed FP length of 49.345 m 
Low TOF-bin boundary 
High TOF-bin boundary 
Transmission 

Uncorrelated uncertainty due to counting statistics 
Normalization (uN/N = 0.25 %) 
Background model (uK/K = 5 %) 

Comments from the authors: 
The AGS concept was used to derive the experimental transmission 

T
exp

=

N

C

in

C

out

BK
BK

in

out

and to propagate the uncorrelated uncertainties due to counting statistics and the uncertainty due 
to the normalization (uN/N = 0.25 %) and background model (uK/K = 3 %).  

The quoted uncertainties are standard uncertainties at 1 standard deviation 
The transmission of the measurements with the Ca sample and dummy Al-container are both given. 

References 

C.  Paradela,  K.  Guber,  G.  Alaerts,  J.  Heyse,  S.  Kopecky,  P.  Schillebeeckx,  D.  Vendelbo  and  R.  Wynants,   
"Results of transmission measurements for 40Ca at GELINA", this JRC Technical Report, (2015). 
W.  Mondelaers  and  P.  Schillebeeckx,  "GELINA,  a  neutron  time-of-flight  facility  for  neutron  data 
measurements", Notiziario Neutroni e Luce di Sincrotrone, 11 (2006) 19 – 25. 
P. Schillebeeckx, B. Becker,Y. Danon, K. Guber, H. Harada, J. Heyse, A.R. Junghans, S. Kopecky, C. Massimi, 
M.C.  Moxon,  N.  Otuka,  I.  Sirakov  and  K.  Volev,  "Determination  of  resonance  parameters  and  their 
covariances from neutron induced reaction cross section data", Nucl. Data Sheets 113 (2012) 3054 – 3100. 

10 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
-
-
 
  
 
B.  Becker,  C.  Bastian,  F.  Emiliani,  F.  Gunsing,  J.  Heyse,  K.  Kauwenberghs,  S.  Kopecky,  C.  Lampoudis,  C. 
Massimi, N. Otuka, P. Schillebeeckx and I. Sirakov, "Data reduction and uncertainty propagation of time-of-
flight spectra with AGS", J. of Instrumentation 7 (2012) P11002 –  19. 
M.  Flaska,  A.  Borella,  D.  Lathouwers,  L.C.  Mihailescu,  W.  Mondelaers,  A.J.M.  Plompen,  H.  van  Dam  and 
T.H.J.J.  van  der  Hagen,  "Modeling  of  the  GELINA  neutron  target  using  coupled  electron–photon–neutron 
transport with the MCNP4C3 code", Nucl. Instr. Meth. A 531 (2004) 392 – 406. 
D. Ene, C. Borcea, S. Kopecky, W. Mondelaers, A. Negret and A.J.M. Plompen, "Global characterisation of 
the  GELINA  facility  for  high-resolution  neutron  time-of-light  measurements  by  Monte  Carlo  simulations", 
Nucl. Instr. Meth. A 618 (2010) 54 – 68. 
M.C. Moxon and J.B. Brisland, Technical Report AEA-INTEC-0630, AEA Technology (1991). 

11 

 
 
 
 
 
12 

 
 
 
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Title: Results of transmission measurements for 40Ca at GELINA. 

Author(s): Carlos Paradela, Klaus Guber, Gery Alaerts, Jan Heyse, Stefan Kopecky, Peter Schillebeeckx, 
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