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SBLNF: update on secondary beam line SBLNF meeting 12 th November 2012. M. Calviani , A. Ferrari, R. Losito, P. Sala, Hei . Vincke. Outline. Updates on the m pits Prompt dose rate due m downstream the dump Target design possibilities Updates on the general target station design - PowerPoint PPT Presentation
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SBLNF: update on secondary beam line
SBLNF meeting 12th November 2012
M. Calviani, A. Ferrari, R. Losito, P. Sala, Hei. Vincke
2 M. Calviani, SBLNF meeting
Outline
1. Updates on the m pits2. Prompt dose rate due m downstream the
dump3. Target design possibilities4. Updates on the general target station design5. RP aspects pit and He-vessel (to be treated
in a separate presentation)
12th November 2012
3 M. Calviani, SBLNF meeting
Updates on the m pit
12th November 2012
Pit1 = 3 m C + 2 m Fe Pit2 = Pit1 + 10 m Fe
4 M. Calviani, SBLNF meeting
Updates on the m pit
Building on top of the m pits necessary for: Access to the two m pits (concrete shielding) Location of the hadron absorber cooling station Location of a potential DP water cooling station (if
needed!) Building will need shielding if the absorber
cooling station will be located there Total dose on the 1st pit ~1 MGy/y
Potentially no human access since first beam Diamond-detector the only option?
12th November 2012
5 M. Calviani, SBLNF meeting
m pits – m spectrum
12th November 2012
“thermalized” m spectrum in both pits We don’t know
from which p these m come from!
Shape remains the same as a function of depth shift the HE part
towards lower energies
For increasing depths
6 M. Calviani, SBLNF meeting
m pits – m parents spectrum
Energy distribution of parents p/K generating m which arrive in the pit1 and pit2
12th November 2012
pit1 pit2~4.
6±0.
5 G
eV >16 GeV
> 3 GeV
7 M. Calviani, SBLNF meeting
m pits – sensitivity to misalignment
Sensitivity to proton steering on target
Primary beam 2 mm of target: ~5 cm off-
centre @pit1 ~35 cm off-
centre @pit2
12th November 2012
~35 cm
~5 cm
PRELIMINARY
8 M. Calviani, SBLNF meeting
m pits – sensitivity to misalignment
Effect on horn/reflector 8 mrad misalignment
12th November 2012
Target/horn tilted by 8mrad (0.5 deg) Reflector tilted by 8mrad (0.5 deg)
PREL
IMIN
ARY
PREL
IMIN
ARY
Pit1 very sensitive!
~40 cm, deformed spectrum
~40 cm
Pit2 sensitive only to very high energy m!
9 M. Calviani, SBLNF meeting
m pits – preliminary conclusions
The foreseen location of the pits are well adapted to sample the neutrino energy of interest Pit1: 2 meters after C core Pit2: 10 meters Fe after Pit1
Important to have at least two pits:1. Alignment (longer arm lever)2. Monitoring of target health (NuMI experience
with failing targets)3. Potential use of m flux for n flux prediction
(normalization)
12th November 2012
10 M. Calviani, SBLNF meeting
H*(10) downstream absorber
The hadron absorber significantly reduces the prompt dose rate downstream and lateral
Still a significant amount of m are present around – contributing to the prompt radiation levels
12th November 2012
Lateral view Top view
11 M. Calviani, SBLNF meeting
H*(10) downstream absorber (vertical view)
12th November 2012
Beam
axi
s
~5 mSv/h
Z = [120-135] m
H*(10) averaged 15 meters downstream the absorber
~5 mSv/h are reached ~8 meters from beam axis
PRELIMINARY
12 M. Calviani, SBLNF meeting
Potential target configuration
3 configurations presently being investigated: “stand-alone” graphite target – CNGS-inspired T2K-like target (inside horn) Air/He-cooled beryllium target
For the moment being investigated in parallel Material choices limited to graphite &
beryllium Energy deposited in the target ~2 kW (for
~240 kW beam power)
12th November 2012
13 M. Calviani, SBLNF meeting
Target inside horn
12th November 2012
Magnetic field
Thickness minimum possible to maximize magnetic field inside horn
Proton beam
14 M. Calviani, SBLNF meeting
Target outside horn:
12th November 2012
Magnetic field
Proton beam
15 M. Calviani, SBLNF meeting
Potential target configuration
12th November 2012
For both solution the present conceptual design is to have a passive or actively He-cooled target
Advantages DisadvantagesTarget inside horn
Higher pion collection from target
More difficult maintenance and construction
Less degree of freedom for target design
Electrical coupling between target/horn
Max target temperature limited by horn inner conductor
Target outside horn
Easier maintenance and installation
More degree of freedom for a more robust design
Less efficient in pion collection
16 M. Calviani, SBLNF meeting
Optimisation of target size
12th November 2012
17 M. Calviani, SBLNF meeting
Solution #1 Target outside horn:
Graphite target, He-flow active cooling (closed loop) Passive cooling (CNGS) should be excluded due to the high
air flow required to cool the external tank High temperature graphite advantageous for material
properties (reduction of radiation damage) Structural support can be a CNGS-similar configuration Design possible only if outside horn
12th November 2012
heliumProton beam
He inlet He outlet
Lateral view
He inlet He outlet
18 M. Calviani, SBLNF meeting
Solution #2 Target inside/outside horn:
T2K approach (graphite target, high temperature)
Closed-loop Cantilever design He-cooled target (requirement of O2<100 ppm)
12th November 2012
heliumProton beam
19 M. Calviani, SBLNF meeting
Solution #3 Target inside horn:
Graphite/beryllium (low temperature – horn internal conductor)
He cooling Cantilever design MiniBooNE-inspired design (open loop)
Beryllium rod and cooling fins (extruded from a bigger block) “Open” circuit design possible
12th November 2012
Proton beam
Extra
ctio
n +
purifi
catio
n lo
op?
Lateral view Front view
helium
20 M. Calviani, SBLNF meeting
Energy deposition in target
12th November 2012
4 mm radius targetsbeam = 1 mm
10 mm radius targetsbeam = 2.7 mm
Graphite case (1.8 g/cm3) Similar values for beryllium
Max ~400 J/cm3/pulse Max ~100 J/cm3/pulse
21 M. Calviani, SBLNF meeting
Temperature increase per shot
Graphite and Beryllium, in the “big-target” configuration DTmaxC = ~80 °C/pulse (~250 °C/pulse for “small”) DTmaxBe = ~50 °C/pulse (~135 °C/pulse for “small”)
12th November 2012
graphite beryllium
22 M. Calviani, SBLNF meeting
Energy deposition for “small” target
12th November 2012
Graphite: DTmax~250 °C, 9 MPa compressive stress (~60 MPa max)
Beryllium: DTmax~140 °C, 450 MPa compressive stress (~250 MPa
max) Beryllium small target excluded!
graphite beryllium
A. Perillo-Marcone
23 M. Calviani, SBLNF meeting
Hadron absorber A CNGS-like approach might be followed for the SBLNF Graphite core (water cooled) surrounded by Fe
shielding 45 kW deposited in the graphite (primary beam ~10 cm Ø) 35 kW deposited in Fe
Part of the absorber embedded in the He-vessel Top Fe needed for m prompt dose rate reduction!
12th November 2012
Graphite FeAl water cooling
Al water cooling
Primary beam/hadrons
24 M. Calviani, SBLNF meeting
Roadmap Collaboration with experiments to address the
target position (in/out horn) Detailed thermo mechanical assessment of target
and absorber has started Graphite and beryllium analysis will proceed in parallel
Follow-ups on: Requirements for DP cooling! Requirements for cooling of target chase shielding
elements! Requirements for the target collimator (size/max thermal
load) Objective is to narrow down the main needs
in the next few weeks12th November 2012
25 M. Calviani, SBLNF meeting
Conceptual design for TS buildings
12th November 2012
26 M. Calviani, SBLNF meeting
Conceptual design for TS buildings
12th November 2012
27 M. Calviani, SBLNF meeting
Updates on the target station
design He-vessel: Vessel need to be thick enough
to allow evacuation before accessing the target – T2K are (5)10 cm steel plates
Water or air cooling needed (to be studied)
Avoid concrete shielding in the vessel to avoid 3H production
Dehumidification to be thought from the very beginning (reduce HTO in air)
Fe shielding blocks (top+lateral) in the vessel (desorption of 3H)
12th November 2012
Fe Fe
Fe
Fe
Fe Fe
Fe
Concrete
He vessel layer Not in scale
28 M. Calviani, SBLNF meeting 12th November 2012
Ground (moraine)
Target chase
He vessel (medium blue)
Concrete shielding (red)
Iron shielding (dark blue)
Target station building and vault
Target & horn/reflector
300
cm20
0 cm
300 cm
29 M. Calviani, SBLNF meeting
Conclusions
12th November 2012
m pits well optimized for a low energy neutrino beam
He-vessel adopted as baseline for reduction of air activation
Shielding and cooling needs in the target chase will be analysed taking into account thermo mechanical and RP aspects (water activation)
Few selected target configurations have been considered for more detailed thermo mechanical analyses