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S. Damjanovic, CERN 1 Local Shielding around the PS Straight Section75 ? Sanja Damjanovic, DGS-RP LIU-PS Meeting, CERN, June 11, 2013
S. Damjanovic, CERN 1
Local Shielding around the PS Straight Section75 ?
Sanja Damjanovic, DGS-RP
LIU-PS Meeting, CERN, June 11, 2013
S. Damjanovic, CERN 2
FLUKA Geometry of the Local Shielding around Dummy Septum 15
beam direction
SS15
SS16
Soil, Stainless Steel, Aluminum, Concrete, Air, Steel l
Local shielding in SS15
PS Ejection Region with dummy septum 15
MMU14 MMU15
S. Damjanovic, CERN 3
Details of the Local Shielding around the Dummy Septum
- longitudinal dimension: 100 cm
- lateral dimension: 200 cm
- vertical dimension: 220 cm
Proposal: implement similar shielding around SS75 in order to - reduce the exposure of electronics in the RF alcove next to SS77 - reduce the prompt dose rate at the emergency exit towards EA
S. Damjanovic, CERN 4
FLUKA Geometry of a possible Local Shielding around SS75
Soil, Stainless Steel, Aluminum, Concrete, Steel
beam direction
SS75
PS Sector 8
SS76
local shielding
around SS75
RF Alcove
local shielding in SS75
MMU74
MMU75
MMU74
S. Damjanovic, CERN 5
FLUKA Geometry of the PS Sector 8 including the RF Alcove
Soil, Stainless Steel, Aluminum, Concrete, Steel, Iron l
RF alcove
BE/RF1
BE/RF2
existing concrete shielding block in front of the RF alcove: 160 cm long and 80 cm wide;BE/RF crates locally shielded by iron blocks
SS77 - RF cavity 40MHzSS76 - RF cavity
10MHzSS75-local shielding
6
- for MTE operation, about 13% of the total beam loss (2%) between SS75 and SS80 (with 11% of 13% in SS75)
Assumptions for the Simulation
- For the simulation in the PS Sector 8 use the (normalized) beam loss distribution along sections SS75, 76, 77, 78, 79 and 80 measured by the BLMs as an input to the FLUKA simulations
- absolute normalization: multiply the FLUKA results extracted per primary with the measured beam loss rate of 2.5×1010 p/s (0.25% of the primary 1013 p/s)
for the annual estimate assume 2550 effective hours per year
- proton beam momentum of p=14 GeV - MTE operation at full beam intensity of 1013 p/s; total beam losses 2% - beam losses distributed according to the BLM measurements
6S. Damjanovic, CERN
83% of total loss in Sector 8 measured by BLM in SS75
Continuous Transfer (CT) ejection – beam losses
CT lossesMTE losses
For CT operation highest beam losses in the region of SS31 (electrostatic septum) Large losses also in SS16 and SS75
PS Report CERN-ATS-2011-007 (2011)
Similar distribution of losses between SS75-80 with higher absolute values for the CT
Conclusions to be drawn later for MTE operation would also be valid for CT
SS75
Can the local shielding around SS75 efficiently reduce the exposure of the electronics inside the RF technical alcove next to SS77 ?
Physical Dose -long term ionizing damage-
1MeV-Eq Neutron Fluence -Displacement Damage-
High Energy (Ek>20 MeV) Hadron Fluence - Single Event Error -
to answer the question these quantities should be followed
S. Damjanovic, CERN 9
Dose [Gy/y] distribution w/o and with local shielding in SS75 2-dim projections of Dose in y-z plane averaged over Δx=2 m height
Comparing the color codes, dose inside the RF alcove the same with and w/o local shielding around SS75
Dose [G
y/year]
SS75 w/o local shielding
Distance along y-axis (cm)
Dis
tanc
e al
ong
z-ax
is (c
m)
SS75 locally shielded
z-beam direction, x-vertical, y-horizontal direction
for a nominal MTE operation year with 2.3×10+17 lost p in the region between SS75 and SS80
SS
75
local shielding can hardly reduce downstream radiation (like for SS15)
S. Damjanovic, CERN 10
Detailed comparison of Dose distribution inside the RF Alcove
2-dim projections of Dose in y-z plane averaged over Δx=2 m height
SS75 w/o local shielding SS75 locally shielded
Dose [G
y/year]
Distance along y-axis (cm)
Dis
tanc
e al
ong
z-ax
is (c
m)
BE/RF2
BE/RF1
options RF1 - Dose [Gy/year] RF2 - Dose [Gy/year]
Option I – w/o Local Shielding around SS75 2.7±0.2 5.4±0.3
Option II – with Local Shielding around SS75 2.9±0.2 5.0±0.3
Option III – without present block in front of alcove 4.0±0.3 7.7±0.3
Hardly any reduction of the dose in the two BE/RF crates with the additional local shielding around SS75
Present shielding block reduces the dose inside the BE/RF1 and RF2 only by factors of 1.3 and 1.5, resp.
for a nominal MTE operation year with 2.3×10+17 lost p in the region between SS75 and SS80
S. Damjanovic, CERN 11
Dose distribution – solely contribution from the losses inside SS75
for a nominal MTE operation year with 0.8×2.3×10+17 lost p in the SS75
options RF1 - Dose [Gy/year] RF2 - Dose [Gy/year]
all sources contribution from source in SS75 all sources contribution from
source in SS75
w/o Local Shielding around SS75 2.7 1.1 5.4 2.5
with Local Shielding around SS75 2.9 1.2 5.0 2.0
Lack of any shielding effect also visible in the isolated contribution from SS75
S. Damjanovic, CERN 12
Distribution of high energy (Ek>20 MeV) hadron fluence w/o and with local shielding in SS75
2-dim projections in y-z plane averaged over Δx=2 m height
As for the dose, no effect of the shielding in the RF alcove
Distance along y-axis (cm)
for a nominal MTE operation year with 2.3×10+17 lost p distributed between SS75 and SS80
h [1/cm2/year]
SS75 w/o local shielding
Dis
tanc
e al
ong
z-ax
is (c
m)
SS75 locally shielded
S. Damjanovic, CERN 13
Detailed comparison of HE hadron fluence inside the RF Alcove
2-dim projectionsin y-z plane averaged over Δx=2 m height
SS75 w/o local shielding SS75 locally shielded
h [1/cm2/year]
Distance along y-axis (cm)
Dis
tanc
e al
ong
z-ax
is (c
m)
BE/RF2
BE/RF1
options RF1 - h [1/cm2/year] RF2 - h [1/cm2/year]
Option I – w/o Local Shielding around SS75 8.3×109 1.3×1010
Option II – with Local Shielding around SS75 8.3×109 1.3×1010
Option III – without present block in front of alcove 9.3×109 2.1×1010
No reduction of the hadron fluence in the two BE/RF crates with the additional local shielding around SS75
for a nominal MTE operation year with 2.3×10+17 lost p in the region between SS75 and SS80
Present shielding block reduces the h-fluence inside the BE/RF1 and RF2 only by factors of 1.1 and 1.6, resp.
S. Damjanovic, CERN 14
Distribution of 1MeV-eq neutron fluence w/o and with local shielding in SS75
2-dim projections in y-z plane averaged over Δx=2 m height
for a nominal MTE operation year with 2.3×10+17 lost p distributed between SS75 and SS80
1MeV-eq n [1/cm
2/year]
SS75 w/o local shielding
Distance along y-axis (cm)
Dis
tanc
e al
ong
z-ax
is (c
m)
SS75 locally shielded
Again no effect of the shielding in the RF alcove
S. Damjanovic, CERN 15
Detailed comparison of 1MeV-eq neutron fluence in the RF Alcove
2-dim projectionsin y-z plane averaged over Δx=2 m height
SS75 w/o local shielding SS75 locally shielded 1MeV-eq n [1/cm
2/year]
Distance along y-axis (cm)
Dis
tanc
e al
ong
z-ax
is (c
m)
BE/RF2
BE/RF1
options RF1 – 1MeV-eq neutron [1/cm2/year]
RF2 – 1MeV-eq neutron [1/cm2/year]
Option I – w/o Local Shielding around SS75 9.7×1010 1.2×1011
Option II – with Local Shielding around SS75 9.5×1010 1.2×1011
Option III – without present block in front of alcove 1.2×1011 1.9×1011
No reduction of the 1MeV-eq neutron fluence in the two RF crates with the additional local shielding around SS75
for a nominal MTE operation year with 2.3×10+17 lost p in the region between SS75 and SS80
Present shielding block reduces the 1MeV-eq-n-fluence inside the BE/RF1 and RF2 only by factors of 1.3 and 1.5, resp.
Fluence Spectra scored in the volume of the two BE/RF crates
Local shielding of two BE/RF crates by the Fe walls most effective way to reduce the exposure of the electronics (up to a factor of 10; see my slides shown at 10th MCWG meeting 04/2012)
Small effects of the present concrete block: reduction by factors 1.2 and 1.6 for the BE/RF1 and RF2 ,resp (see remarks below).
Local shielding around SS75 cannot reduce the exposure of the electronics inside the RF technical alcove
Can the local shielding around SS75 efficiently reduce the prompt dose rate at the emergency exit towards the EA location (exit door D113)?
S. Damjanovic, CERN 18
Stray radiation w/o and with local shielding in SS75 2-dim projections of Dose Rate in y-z plane averaged over Δx=2 m height
Dose R
ate [mS
v/h]
SS75 w/o local shielding
Distance along y-axis (cm)
Dis
tanc
e al
ong
z-ax
is (c
m)
SS75 locally shielded
z-beam direction, x-vertical, y-horizontal direction
for beam loss rate 2.54×10+10 p/s between SS75 and SS80
MM
U75Chicane
How much is the stray radiation reduced at the entrance to the Chicane ?
S. Damjanovic, CERN 19
Stray radiation w/o and with local shielding in SS75 2-dim projections of Dose Rate in y-z plane averaged over Δx=2 m height
Dose R
ate [mS
v/h]
SS75 w/o local shielding
Distance along y-axis (cm)
Dis
tanc
e al
ong
z-ax
is (c
m)
SS75 locally shielded
z-beam direction, x-vertical, y-horizontal direction
for beam loss rate 2.54×10+10 p/s between SS75 and SS80
MM
U75Chicane
How much is the stray radiation reduced at the entrance to the Chicane ?
S. Damjanovic, CERN 20
Dose Rates along the tunnel wall – side towards the EA
Prompt radiation at the entrance to the chicane reduced by only ~20%
1 dim projections along z (beam direction) averaged over Δy=40 cm from the tunnel wall
(already downstream enough to not get any benefit) is
Addendum Remarks on the present concrete shielding block
S. Damjanovic, CERN 21
S. Damjanovic, CERN 22
Dose [Gy/y] distribution w and w/o concrete block 2-dim projections of Dose in y-z plane averaged over Δx=2 m height
Comparing the color codes, the dose inside the RF alcove similar with and w/o concrete block – size and position of the block ineffective
Dose [G
y/year]
SS75 w/o local shielding
Distance along y-axis (cm)
Dis
tanc
e al
ong
z-ax
is (c
m)
SS75 locally shielded
z-beam direction, x-vertical, y-horizontal direction
for a nominal MTE operation year with 2.3×10+17 lost p in the region between SS75 and SS80
S. Damjanovic, CERN 23
Distribution of high energy (Ek>20 MeV) hadron fluence with and w/o concrete block in front of the RF Alcove
2-dim projections in y-z plane averaged over Δx=2 m height
Comparing the color codes, the h-fluence inside the RF alcove similar with and w/o concrete block
Distance along y-axis (cm)
for a nominal MTE operation year with 2.3×10+17 lost p distributed between SS75 and SS80
h [1/cm2/year]
SS75 w/o local shielding
Dis
tanc
e al
ong
z-ax
is (c
m)
SS75 locally shielded
S. Damjanovic, CERN 24
Distribution of 1MeV-eq neutron fluence with and w/o concrete block in front of the RF Alcove
2-dim projections in y-z plane averaged over Δx=2 m height
Comparing the color codes, the 1MeV-eq neutron fluence inside the RF alcove similar with and w/o block
for a nominal MTE operation year with 2.3×10+17 lost p distributed between SS75 and SS80
1MeV-eq n [1/cm
2/year]
SS75 w/o local shielding
Distance along y-axis (cm)
Dis
tanc
e al
ong
z-ax
is (c
m)
SS75 locally shielded
S. Damjanovic, CERN 25
h [1/cm2/y] RF1 - h [1/cm2/year] RF2 - h [1/cm2/year]
Option I – w/o Local Shielding around SS75 8.3×109 1.3×1010
Option II – with Local Shielding around SS75 8.3×109 1.3×1010
Option III – without present block in front of alcove 9.3×109 2.1×1010
1MeV-eq neutron [1/cm2/y] RF1 – 1MeV-eq neutron [1/cm2/year]
RF2 – 1MeV-eq neutron [1/cm2/year]
Option I – w/o Local Shielding around SS75 9.7×1010 1.2×1011
Option II – with Local Shielding around SS75 9.5×1010 1.2×1011
Option III – without present block in front of alcove 1.2×1011 1.9×1011
Dose RF1 - Dose [Gy/year] RF2 - Dose [Gy/year]
Option I – w/o Local Shielding around SS75 2.7±0.2 5.4±0.3
Option II – with Local Shielding around SS75 2.9±0.2 5.0±0.3
Option III – without present block in front of alcove 4.0±0.3 7.7±0.3
Small effects of the present concrete block:exposure of the electronics reduced only by factors of 1.2 and 1.6 for the BE/RF1 and RF2 ,resp.
