P. Baumann, P. Duperrex, S. Jollet, A. Knecht, D. Laube, C ...
Post on 20-Jun-2022
1 Views
Preview:
Transcript
WIR SCHAFFEN WISSEN – HEUTE FÜR MORGEN
Progress and challenges of the PSI Meson targets and relevant systems
Daniela Kiselev :: Department head ASA :: Paul Scherrer InstitutP. Baumann, P. Duperrex, S. Jollet, A. Knecht, D. Laube, C. Nyfeler, D. Reggiani, R. Sobbia, V. Talanov, M. Wohlmuther
The 3rd J-PARC Symposium (J-PARC2019)September 23-26, 2019, Tsukuba, Japan
Accelerator Facilities at PSI
p-Therapy250MeV, <1µA
Swiss Light Source2.4GeV, 400mA
High Intensity Proton Accelerator590 MeV, max. 2.4mA
SWISSFEL 5.8 GeV
Central control room
SINQ Spallation Neutron SourceUCN
The PSI Proton Accelerator Facilities
HIPA (High Intensity Proton Accelerator)- CW (50.63 MHz), 590 MeV, - up to 2.4 mA(1.44 MW) - 2 meson production targets - 7 secondary beam lines- SINQ and UCN spallation source
Page 3
PROSCAN (Proton therapy): since 2007Comet: superconducting cyclotronCW, 250 MeV, up to 1 µA protonsmedical treatment:3 Gantries, 1 Eye Cancer Treatment StationIrradiation Station: PIF
PIF
SecondaryBeam Lines
hot cell HIPA
Gantry 1, 2 3Target M
Comet
Target E
Spallation neutron source SINQ
Injector II
Injector IECR-source &Cockroft-Walton
OPTIS
Ring
UCN
μ/π Secondary Beam Lines
Seite 4
Target E
p-Beam Spin rotator
πE1
μE1μE4
πM1
πM3
πE5
Target M
πE3
Target M:πM1: 100-500 MeV/c PionsπM3: 28 MeV/c Surface Muons
Target E:πE1: 10 - 500 MeV/c High Intensity Pions und MuonsμE1: Polarized Muon BeamπE3: 28MeV/c Surface polarized MuonsμE4: 30 - 100 MeV/c High Intensity Polarized MuonsπE5: 10 - 120 MeV/c High Intensity Muons
Challenges for meson production targets
• Power deposition: at 2.4 mA, 590 MeV protons ~ 50 kW on Target E cooling high temperature resistant material thermal stress
• Radiation damage: embrittlement deformation (also due to heating) loss of conductivity
Approach:• distribute power:
rotating wheel with 1 Hz needs bearings• cooling by radiation:
- independent of conductivity- local shielding (Cu) is cooled by water
p-beam
Target E
Drive shaft Motor
• Motor: 2.5 m above the beam lineFunctioning is not affected by irradiation life time ~ 5 – 8 years
Targetwheel
Watercooling
Localshielding
deep grooveball bearings
angular contactball bearings
140 oC
50 oC
Challenges for meson production targets
• Wheel deformation reduced by- polycrystalline graphite isotropic properties- slits in wheel rim für thermal expansion
- spokes: allows thermal expansion of target conehollow to avoid high temperature at bearing
12 segments with 1 mm slit
1700 K
Critical components: Bearings
No grease as lubrication! brittle due to hard irradiationso called radiation hard grease does not help proofed
Balls Si3N4, GMN, GermanyCoating: MoS2, Ag for ring & cage1 -2 x exchange/year Graphite wheel lasts muchlonger: ~ 4Years (39 Ah record)
• Ball bearings:
in use:
Shun Makimura(JPARC)
in test:
Balls stainless steel + WS2 blocks Koyo, JapanTest (without radiation): > 420 daysTest in beam at PSI planned next year
Monitoring of the motor currentcu
rren
t[A
]
0
1
2
3
4
5
averagemotor current
new bearing
Targ
et E
Exc
hang
e
peakmotor current
rotation/min
beam current
Extraction of Target E insert
Exchange flask: − 45 t, shielded with 40 cm steel− remotely operated
Working platform:− ~ 2m above beamline, shielded with steel− Accessible after removing 3 – 4 m of concrete
"Bridge":− contains contamination protection− door to close lifting hole− sticks for positioning of the flask
Transport of 2. target insert to beamline
Seite 10
open closedparking lot
sluice to hotcell
To save time:Spare Target E insert is taken out from the parking lot
Exchange flask on parking lot
At the same time:Reparing of the insert from beamline in hotcell
Transport to hotcell PSI West (ATEC)
Exchange of bearings with manipulatorView into hotcell of ATEC
Hub
− Remote handling necessary: up to 3 Sv/h− Handing over from flask to hotcell via sluice
Usually only the hub needs to be exchanged not much radioactive waste (up to 200 mSv/h)
Design of the hotcell ATEC
Seite 12
ATEC: 2. service cell in 2019− wall in between can be opened vertically
Advantage:− in case of unavoidable access to one service cell (in case of failure),
radioactive components are moved to the other service cell.− less personal dose rate during cleaning:
drums with rad. waste can be moved temporarly to the other service cell.
2. Service cell 1. Service cell
Sluice in between Sluice for Target E
Room for personal
Sluice pulled up by external crane
Moved byATEC crane
Standard equipment of hotcell ATEC
6 high-resolution cameras/service cell
1 power manipulator/service cell
"cold" handin control room
"hot" handin service cell
for wall shielding
+ 1 leadglass window+ 1 dosimeter+ a trolley to move things around
(up to 60 t)+ 1 crane/cellmovable over 2 service cells(important, if 1 crane fails)
Gripfor camera
Target E93 in April 2012: 33.5 Ah ~ 3.5 years
Tilt of the segments observed! Quantitative measurement
of tilt in hot cell (ATEC) Displacement up to -2 mm Shrinking of about 1% at 39Ah likely due to radiationWhy only E93?
A closer look to the target E93 after irradiation
Target development I: Target E with grooves
Seite 15
Grooves inside and outside − with different frequencies:
114 Hz and 138 Hz− to distinguish beam left and right
from center− different depths:
0.3mm, 0.5mm, 0.7mm, 0.9mm− to find comprommise between
losses and signal
Purpose: Beam centering on the 6 mm rim of Target E
Idea:Modulation of the beam current measurement (MHC5) after Target E Strength of the signal is a measure for the deviation of the beam from center
Modulation of beam current at 0.75 mA after Tg E
Page 16
1 1.5 2 2.5
time [sec.]
-0.01
0
0.01
[mA]
AC part of the beam intensity monitor MHC5 raw signal
1 1.5 2 2.5
time [sec.]
-0.01
0
0.01
[mA]
MHC5 filtered signal
With Filter
Raw signal
1 s
1 Hz: period of the target wheel12 Hz: 12 Slits: broad due angle
Slits
Modulation due to grooves
Modulation due to grooves not seen by eye and effected by noise Frequency analysis (FFT) necessary
MH
C4*T
-MH
C4M
HC4
*T-M
HC4
MHC4: current before Target ET: transmission: for 60 mm target T = 0.6MHC5: current behind Target E
Signal as a function of position
Seite 17
• Very sensitive method of ~factor 10 in signal change!• Much more sensitive than transmission T = MHC5/MHC4
59.1
59.15
59.2
59.25
59.3
59.35
Target
-E tran
smissi
on [%]
1.6 mA (MHC4)
-1.5 -1 -0.5 0 0.5 1 1.5
AHPos [mm]
0
1
2
3
4
5
6
7
Mod
ulat
ion
Ampl
itude
[a.u
.]
F=138Hz
F=114Hz
Deviation from center of Target E [mm]-1.5 -1 -0.5 0 0.5 1 1.5
Ampl
itude
ofm
odul
atio
n
7
6
5
4
3
2
1
0
114 Hz138 Hz
-1 -0.5 0 0.5 1
Tran
smiss
ion
59.1
59.2
59.3- Small change in
Transmission- Slower than
modulationanalysis
Target development II: Slanted Target E
Beam
Standard Target E Slanted Target E
effective 40 mmgraphite target Geant4 simulation:
30 – 60 % forsurface muon production(A. Papa talk)
40 m
m
Proton beam
100
mm
oCAnsys simulation:
More thermal stress due to inhomogeneoustemperature distribution Deformation??
Seite 19
Test with slanted type target out of Aluminum
Test of slanted type target
Test End of November 2019 in Target E vacuum chamber
Slanted target:very tight!
Needs to be tested first!
on bothtargetinserts
There should be 8 – 10 mm space
in parking slot= same dimensionsthan in beamline
Target-M
P-BEAM
Target M:
Mean diameter: 320 mm
Target thickness: 5.2 mm
Target width: 20 mm
Graphite density: 1.8 g/cm3
Beam loss: 1.6 %
Power deposition: 2.4 kW/mA
Temperature: 1100 K
Irradiation damage: 0.1 dpa/Ah
Rotational Speed: 1 Hz
Current limit: 5 mA
Life time: up to several years
up to ~ 60 Ah ~ 6 DPA
.
Improved design(2013)
Target-M insert
Drive-motor
p
(old) Target M insert mounted on wheels
π, µ
π, µ
Design of the new Target-M insert (2012)
• improved vacuum flange: seal can be exchanged/cleaned• drive shaft: better heat protection for the bearings
1. part made from Ti-V ( instead of steel) to prevent heat conduction• additonal cooled Cu- plate better cooling and protection of bearings
against radiated heat
VacuumChamber
Graphite Wheel
TungstenCollimator
TemperatureSensors
Drive-Motor
Proton-Beam
Secondarybeamlines
CooledCu-plate
TiVshaft
Steel shaft
Future Project: High Intensity Muon Beam (HIMB)
Seite 23
slanted 20 mm graphite wheel
2 solenoids close to target
Factor 100 more Muons
Many constraints due to present beamline Feasibility study will start soon
Present design:
Future design:
5 mm graphite
Talk A. Papa
Summary
• Introduction to the PSI High Intensity Proton Accelerator (HIPA)
• Extraction from the Ring Cyclotron
• Beam transfer to the meson production targets M/E and SINQ spallation source
• Beam diagnostics for setup & optimization
• Feasibility study of beam rotation for SINQ
• Beam switchover to the UCN source
• Conclusion
PSI Meson target facility M and E with several beamline: π, µ Bearings are critical for Target E For exchange infrastructure needed: exchange flask, hot cell New target designs: grooves for beam position diagnostics Slanted target for test and higher muon rates Target M: Ideas for increasing muon rate by factor 100 (HIMB project)
Page 24
PSI congratulates to 10 years of J-PARC
top related