Christos Lamboudis HEP 17-20 April. Athens
Study ofMDT response to neutrons andpossible ageing effects
Do we really need to worry about neutrons?Do we really need to worry about neutrons?
If so, then we have run some tests with realneutronsIf so, then we have run some tests with realneutrons
Where can we find proper neutron beam sources?Where can we find proper neutron beam sources?
Detailed description of the beam facilitiesDetailed description of the beam facilities
Conclusion - ProposalConclusion - Proposal
Christos Lamboudis HEP 17-20 April. Athens
Christos Lamboudis HEP 17-20 April. Athens
Are neutrons worth to bother?
Highly ionizing neutrons can produce charge,much larger compared with that of a muonHighly ionizing neutrons can produce charge,much larger compared with that of a muon
electronics recovery time?electronics recovery time?
detector’s lifetime? detector’s lifetime?
Triggers induced by background neutrons? Triggers induced by background neutrons?
Neutron interactions with detector wall materials? Neutron interactions with detector wall materials?
Ageing effects?Ageing effects?
Christos Lamboudis HEP 17-20 April. Athens
Christos Lamboudis HEP 17-20 April. Athens
So, what we really have toknow…
expected neutron background ratesexpected neutron background rates
sensitivity of all muon detectorcomponents, as a function of particleenergy(lack of experimental data)sensitivity of all muon detectorcomponents, as a function of particleenergy(lack of experimental data)
neutron cross sections (gas mix.-materials..)neutron cross sections (gas mix.-materials..)
Christos Lamboudis HEP 17-20 April. Athens
Christos Lamboudis HEP 17-20 April. Athens
Need for proper neutron beamfacility.Probably available:
NCSR Tandem(Van de Graaf 5.5MV) accelerator. NCSR Tandem(Van de Graaf 5.5MV) accelerator.
info: neutron energy up to 27MeVinfo: neutron energy up to 27MeV
site : Demokritos Institute, Athens-Greecesite : Demokritos Institute, Athens-Greece
(already running !!)(already running !!)
n_TOF facility (PS213 experiment, CERN)
info: spallation neutron source with energy range
from thermal to GeV
site: TOF facility, CERN-Geneva Switzerland
Christos Lamboudis HEP 17-20 April. Athens
TANDEM T11/25 H.V.E.C 5.5MV
Demokritos TANDEMaccelerator
Christos Lamboudis HEP 17-20 April. Athens
Christos Lamboudis HEP 17-20 April. Athens
TANDEM key features
Van de Graaf typeVan de Graaf type
5.5MV acceleration voltage5.5MV acceleration voltage
Deuteron beam path : analyzer magnet beamchopper switching magnet Ta collimator(2r=5mm) gas cellDeuteron beam path : analyzer magnet beamchopper switching magnet Ta collimator(2r=5mm) gas cell
Gas cell dimensions : length (3.7-5.7cm)Gas cell dimensions : length (3.7-5.7cm)
(stainless steel) ext.diameter (1cm) (stainless steel) ext.diameter (1cm)
wall thickness (0.2mm) wall thickness (0.2mm)
Gas cell entrance window : Mo/Ti foil(5/2.5mg/cm2)Gas cell entrance window : Mo/Ti foil(5/2.5mg/cm2)
Pressure : ~ atmPressure : ~ atm
Beam stop : Pt 0.9 mm foilBeam stop : Pt 0.9 mm foil
Christos Lamboudis HEP 17-20 April. Athens
The neutron production cellassembly
Christos Lamboudis HEP 17-20 April. Athens
Properties of some (d,n) reactions
Reaction
D(d,n)3He
D(3H,n)4He
7Li(p,n)7Be
12C(d,n)13N
14N(d,n)15O
7Li(d,n)8Be
Q Value(MeV)
3,265 ± 0,018
17,578
-1,882 ± 0,002
-0,281 ± 0,003
5,1
15,0
En0 for
Ed=0 (MeV)
2,45 (NCSR)
14,1 (NCSR)
0,12*
4,8
13,3
Christos Lamboudis HEP 17-20 April. Athens
d+dtotal reaction cross section as a function of incident deuteronenergy
Christos Lamboudis HEP 17-20 April. Athens
d+ttotal reaction cross section as a function of incident deuteronenergy
Christos Lamboudis HEP 17-20 April. Athens
d+dneutron energy angular distribution
Christos Lamboudis HEP 17-20 April. Athens
d+3Hneutron energy angular distribution
Christos Lamboudis HEP 17-20 April. Athens
General layout of the PS213 experiment
Christos Lamboudis HEP 17-20 April. Athens
N_TOF facility-CERN
Neutron beam lineNeutron beam line
Pb target
Christos Lamboudis HEP 17-20 April. Athens
n_TOF : Basic Parameters
Proton beamProton beam
Proton beam momentum : 20GeV/cProton beam momentum : 20GeV/c
Intensity : 7 x 1012 p/pulse (dedicated) or 4 x 1012 p/pulse (parasitic)Intensity : 7 x 1012 p/pulse (dedicated) or 4 x 1012 p/pulse (parasitic)
Repetition frequency : 1 pulse/2.4secRepetition frequency : 1 pulse/2.4sec
Spallation moduleSpallation module
Material : LeadMaterial : Lead
X,Y,Z dimensions : 80 x 80 x 60 (cm3)X,Y,Z dimensions : 80 x 80 x 60 (cm3)
TOF tubeTOF tube
Total length : 199.607m (mostly stainless steel)Total length : 199.607m (mostly stainless steel)
Internal diameter : [80 – 40] cmInternal diameter : [80 – 40] cm
Two collimators used for beam modificationTwo collimators used for beam modification
Christos Lamboudis HEP 17-20 April. Athens
Energy distribution of the neutrons at the exit of the Pb target(black) and the sample position of the EAR (red)
Christos Lamboudis HEP 17-20 April. Athens
Beam profile
Christos Lamboudis HEP 17-20 April. Athens
Neutron flux (EAR-1),using differentexperimental techniques
10-2
1
102
104
106
108
En(eV)
Christos Lamboudis HEP 17-20 April. Athens
Conclusions
Need for more experimental data Need for more experimental data
TANDEM irradiation test (real time…),waiting for results! TANDEM irradiation test (real time…),waiting for results!
n_TOF test n_TOF test
In beam irradiationIn beam irradiation
2nd collimator area2nd collimator area