Roesti

SINBAD ABSTRACT NEA-1552/10
ROESTI

1. Name of Experiment:
------------------
Rösti I, II and III.

2. Purpose and Phenomena Tested:
----------------------------
Space distribution of hadron and low-energy neutron fluences and absorbed doses
in the cascades induced in iron and lead dumps irradiated by high-energy hadron
beams.

3. Description of Source and Experimental Configuration:
----------------------------------------------------
The experiments Rösti I (Ref. [1]) and III (Ref. [3]) were performed at the
H6 secondary beam in the North Experimental Area of the CERN SPS (Super Proton
Synchrotron). The beam consisted of positive hadrons (2/3 protons and 1/3
positive pions) with a momentum of 200 GeV/c. The beam had a gaussian profile
with standard deviations of the projected horizontal and vertical beam profile
distributions equal to 1.2 and 0.9 cm respectively.

Experiment Rösti II (Ref. [2]) took place at an extracted beam of the CERN PS
(Proton Synchrotron). The beam consisted of protons of 24 GeV/c momentum,
with a Gaussian profile of standard deviation 0.13 cm in both the horizontal
and the vertical direction.

In Rösti I and II the target was a dump made of twenty 5 cm thick, 30x30 cm square
iron plates. The density of the iron was 7.86 +/- 0.02 g/cm3.
The plates were welded to an iron framework with gaps of 0.7 cm between the plates.
Extra detector slots were provided in front of the first plate (slot 0) and behind
the last plate (slot 20). A sketch of the dump is given in Fig. 1.
The beams were incident on the centre of the first absorber slab.
Aluminium plates, 0.4 cm thick, 24 cm wide and 30 cm high, were inserted into each
slot excepted slot 9, which was left empty. Aluminium disks of varying sizes were
punched out of the plates at different radial distances from the center and several
of them were used as activation detectors. Other detectors (RPL glasses inside
polyethylene capsules of 0.8 cm internal diameter, sulphur and indium disks) were
placed in the remaining holes. A sketch of a detector plate containing the aluminium
samples is given in Fig. 2.

In Rösti III the target was a dump made of twenty 5 cm thick, 50x50 cm square lead
plates. The density of the lead was not measured. The lead composition was known
to include a small amount of antimony (about 4%).
The lead plates were bolted together with 0.8 cm gaps and placed on an iron
support structure. A sketch of the dump is given in Fig. 3.
The beam was incident on the first absorber slab 10 cm off-centre in the horizontal
mid-plane.
Activation detectors, mounted on aluminium plates 0.05 cm thick and with 50x50 cm
lateral dimensions, included aluminium, indium, sulphur and polyethylene disks.
A slight azimuthal asymmetry around the nominal beam axis was found for the detectors
with the highest activation threshold (but not for the others). The data reported
for each radial distance are the aritmetic mean of different azimuthal detector
positions.

4. Measurement System and Uncertainties:
-------------------------------------

Activation detectors:
--------------------

¹¹⁵In(n,n')^115mIn: indium disks of 1.0 cm diameter, 0.36 cm thick. 336 keV gammas
measured with a GeLi detector (absolute emission probability assumed = 46.7%)
³²S(n,p)³²P: sulphur pellets of 2.3 cm diameter, 0.6 cm thick (thickness larger than
max. range of emitted beta particles). Betas were measured with a thin-window
GM tube calibrated with a thick sulphur sample irradiated by neutrons from a
PuBe source of known yield. Note that the original calibration, on which the
results reported in Ref. [1], [2] and [3] were based, was later found incorrect.
The numerical data available here are based on the new correct calibration.
²⁷Al(n,α)²⁴Na: aluminium disk thickness 0.4 cm (Rösti I) or 0.05 cm (Rösti II
and III). Diameter: 1.0 to 3.0 cm (Rösti I & II), 1.0 to 4.0 cm (Rösti III)
(increasing with radial distance). 2.754 MeV gammas were measured with a
3"x3" NaI detector covered by a perspex cap.
²⁷Al(h,spall)¹⁸F: same disks and measuring apparatus as for the previous detector.
Annihilation photons of 0.511 MeV energy were measured by placing the disks
between two sheets of perspex to ensure annihilation close to the source.
¹²C(x,xn)¹¹C: polyethylene disks 0.04 cm thick, with a 1.5 to 3.5 cm diameter
(increasing with radial distance). These detectors were used only in the
Rösti III experiment. The experimental data are not available.

The measured activities were corrected for decay during and after the irradiation
and during counting. A correction for non uniformity of the beam intensity was
also made, based on several monitors.

The presence of the detectors was not considered in the calculational models
described in chapter 5. The aluminium detectors were cut out of the aluminium
support plates, so only the plates must be considered. The other detectors were
generally too small or of too small density to affect the development of the shower.

Dosimeters:
----------

Schott-Jenner DOS2 Radiophotoluminescent dosimeters (RPL): glass rods 0.6 cm long
and with a 0.1 cm diameter, read with a Toshiba FGD-6 reader. The composition is
the following (in weight %): O-53.7%, P-33.4%, Al-4.6%, AG-3.7%, Li-3.7%, B-0.9%
(A_eff ~ 19, Z_eff ~ 10).
These detectors were used only in the Rösti I and Rösti II experiments.

A photo of a bare RPL and an irradiated one (braun) in the tube is shown here.
(An RPL becomes brown when it is irradiated to very high doses, which was never
the case in these experiments. So, only the bare RPL in the picture corresponds to
those used).
In the simulations, the RPL geometry was not reproduced in detail (they were too
small to get enough scoring statistics and to affect particle transport) but in a
first phase dose was scored at their position, assuming a composition of 54% Oxygen
and 46% "Aluminium equivalent". After some tests, it was found that scoring simply
dose in aluminium was giving the same results (in the mixed fields of hadronic
cascades, dose depends only very weakly on atomic number).

Uncertainties:
--------------
The authors estimate that the results should have typical uncertainties of
few percents, maximum 10%. Detectors were positioned by taping them
with adhesive tape at positions known with the normal accuracy available
with a measurement tape (typically about 1 mm, to be compared with detector
diameters of the order of 1 cm)

5. Description of Results and Analysis:
-----------------------------------
The measured results are given in files rosti1.exp, rosti2.exp, rosti3.exp.
In the tables the standard deviations represent the spread of several measurements
from different azimuthal detector positions.

Calculations have been performed with FLUKA92 (Ref. [4], [5]) and with HETC88
(Ref.[6]).
The following FLUKA92 input files prepared by J. Zazula are included here as a
guide for the computational model development:
- fl24fe1.inp: FLUKA92 input for iron dump, 24 GeV/p (act. detectors)
- fl24fe2.inp: FLUKA92 input for iron dump, 24 GeV/p (absorbed dose)
- fl200fe1.inp: FLUKA92 input for iron dump, 200 GeV/h (act. detectors)
- fl200fe2.inp: FLUKA92 input for iron dump, 200 GeV/h (absorbed dose)
- fl-24pb.inp: FLUKA92 input for lead dump, 24 GeV/p (act. detectors)
- fl-200pb.inp: FLUKA92 input for lead dump, 200 GeV/h (act. detectors)

The input files are sufficient for a description of the geometry of the
experiment, but the complete analysis included also several user routines
which are not included here.
Unfortunately input files are not all consistent with each other. For
instance some of the inputs for the Pb dump use a symmetrical geometry, while
others describe more accurately the actual geometry, with the beam hitting
the dump off-center. Also the material composition may appear to be with or
without a small amount of antimony.

Note also that these files refer to a very old version of the code and are
made available mainly to help in the geometry and material description.�Many
defaults have now changed, and most settings should be revised, in particular
those concerning the neutron cross sections (the 37-group library has been
replaced by one with 72 groups).

6. Special Features:
----------------
None

7. Author/Organizer:
----------------

Experiment:
G.R. Stevenson(*), A. Fassò(*), M. Bruzzi(**), C. Furetta(**), P. Giubellino(***),
M.C. Nielsen(*), P.G. Rancoita(**), J.S. Russ(#), R. Steni(***), L. Vismara(**)

Simulation:
A. Fassò(*), A. Ferrari(**), P.R. Sala(**), J. Ranft(##), G.R. Stevenson(*),
J.M. Zazula(###)

(*) Radiation Protection Group, CERN, CH-1211 Geneva 23 (Switzerland)
(**) Istituto Nazionale di Fisica Nucleare, Milano (Italy)
(***) Istituto Nazionale di Fisica Nucleare, Torino (Italy)
(#) Carnegie-Mellon University, Pittsburgh, USA
(##) Leipzig University, Germany
(###) Institute of Nuclear Physics, Cracow, Poland

Compiler of data for Sinbad:
Alberto Fassò
CERN-EP/AIP, CH-1211 Geneve 23 (Switzerland)
e-mail: Alberto.Fasso@cern.ch

Reviewer of compiled data:
I. Kodeli
OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France
e-mail: ivo.kodeli@oecd.org

8. Availability:
------------
Unrestricted

9. References:
----------

[1] J.S. Russ, G.R. Stevenson, A. Fassò, M.C. Nielsen, C. Furetta, P.G. Rancoita
and L. Vismara, "Low-energy neutron measurements in an iron calorimeter
structure irradiated by 200 GeV/c hadrons", CERN/TIS-RP/89-02 (1989) (*)
[2] A. Fassò, G.R. Stevenson, M. Bruzzi, C. Furetta, P.G. Rancoita, P. Giubellino,
R. Steni and J.S. Russ, "Measurements of low-energy neutrons in an iron
calorimeter structure irradiated by 24 GeV/c protons", CERN/TIS-RP/90-19
(1990) (*)
[3] G.R. Stevenson, A. Fassò, C. Furetta, P.G. Rancoita, P. Giubellino, J.S. Russ
and C. Bertrand, "Measurements of low-energy neutrons in a lead calorimeter
structure irradiated by 200 GeV/c hadrons", CERN/TIS-RP/91-11 (1991) (*)
[4] A. Fassò, A. Ferrari, J. Ranft, P.R. Sala, G.R. Stevenson and J.M. Zazula,
"FLUKA simulations of the Rösti experiments", CERN/TIS-RP/IR/92-44 (1992)
[5] A. Fassò, A. Ferrari, J. Ranft, P.R. Sala, G.R. Stevenson and J.M. Zazula,
"A comparison of FLUKA simulations with measurements of fluence and dose
in calorimeter structures", Nucl. Instr. Meth. Phys. Res. A332, 459-468
(1993)
[6] R.G. Alsmiller, Jr., F.S. Alsmiller and O.W. Hermann, "The high-energy
transport code HETC88 and comparisons with experimental data",
Nucl. Instr. Meth. A295, 337-343 (1990)

(*) Note that the ³²S(n,p)³²P activities and the dosimetric data reported in
the original reports were corrected later due to new calibrations.

10. Data and Format:
---------------

DETAILED FILE DESCRIPTIONS
--------------------------
Filename Size[bytes] Content
------------- ------------ -------------
1 rosti.htm 15,304 This information file
2 rosti1.exp 10,484 Rosti I experimental data
3 rosti2.exp 15,427 Rosti II experimental data
4 rosti3.exp 20,205 Rosti III experimental data
5 fl24fe1.inp 11,026 Input data for FLUKA92 code, iron dump, 24 GeV
6 fl24fe2.inp 10,834 Input data for FLUKA92 code, iron dump, 24 GeV
7 fl200fe1.inp 11,083 Input data for FLUKA92 code, iron dump, 200 GeV
8 fl200fe2.inp 16,395 Input data for FLUKA92 code, iron dump, 200 GeV
9 fl-24pb.inp 10,996 Input data for FLUKA92 code, lead dump, 24 GeV
10 fl-200pb.inp 8,916 Input data for FLUKA92 code, lead dump, 200 GeV
11 Fig-1.gif 22,970 Fig. 1: Sketch of the Rosti dump assemblies
11 Fig-2.gif 13,088 Fig. 2: Al sample plate with Al detector sample positions
11 Fig-3.gif 29,484 Fig. 3: Sketch of the Rosti III dump assembly
12 rpl.jpg 35,361 Fig. 4: RPL dosimeter
13 rosti1.sim 8,381 FLUKA92 simulation results for Rosti I
14 rosti2.sim 12,247 FLUKA92 simulation results for Rosti II
15 rosti3.sim 15,866 FLUKA92 simulation results for Rosti III
16 rosti1.pdf 2,456,104 Reference
17 rosti2.pdf 2,772,655 Reference
18 rosti3.pdf 1,996,776 Reference
19 rosti4.pdf 722,383 Reference
20 rosti5.pdf 1,433,487 Reference

SINBAD Benchmark Generation Date: 09/2002
SINBAD Benchmark Last Update: 09/2002

SINBAD ABSTRACT NEA-1552/10 ROESTI

SINBAD ABSTRACT NEA-1552/10
ROESTI