merit (ntof11) experiment: diagnostics
DESCRIPTION
MERIT (ntof11) experiment: Diagnostics. A.Fabich CERN AB-ATB http://cern.ch/proj-hiptarget July 2005. Installation on beam line. Proof-of-principle test of a liquid mercury jet target for multi-MW proton beams. Target chamber. Beam attenuator. Solenoid. Mercury loop. proton beam. - PowerPoint PPT PresentationTRANSCRIPT
July 2005 A.Fabich, CERN AB-ATB 1
MERIT (ntof11) experiment:
DiagnosticsA.FabichCERN AB-ATB
http://cern.ch/proj-hiptarget
July 2005
July 2005 A.Fabich, CERN AB-ATB 2
Installation on beam lineProof-of-principle test of a liquid mercury jet
target for multi-MW proton beams
Beam attenuatorMercury loop Solenoid
proton beam
Target chamber
July 2005 A.Fabich, CERN AB-ATB 3
Target chamber
Cut view
side view
July 2005 A.Fabich, CERN AB-ATB 4
Primary Containment Cross Section
Hg Supply
Hg Jet
PrimaryContainment
Sight GlassCover
Reflector
Sight Glass
Optics
SecondaryContainment
OD=6.18" (157mm) Magnet BoreID = 6.38" (162mm)
~9
cm
July 2005 A.Fabich, CERN AB-ATB 5
Optical Diagnostics
Shadow photography to visually observe mercury jet behaviour
• tight environment
• high radiation area
• high magnetic field: 15 Tesla pulsed
• non-serviceable area
• passive components
• optics only (no active electronics)
• back illuminated with a single fiber laser - pulsed laser X
• transmit image through flexible fiber bundle
July 2005 A.Fabich, CERN AB-ATB 6
Optical Diagnostics
test target
retroreflected illumination
Spherical mirror
laser illumination
image collection
Works OK in this tight environment
cm scale
July 2005 A.Fabich, CERN AB-ATB 7
Radiation hardness
Almost all parts sufficiently radiation hard
BUT the fiber: 0% transmission after
exposure to MERIT equivalent
Search for fiber replacement is ongoing, but alternatives to present scheme have to be investigated …
July 2005 A.Fabich, CERN AB-ATB 8
“Pixel detector”
What kind of pixel detectors are there? ATLAS, CMS enviroment: radiation, B-field,
…
Can we adapt such a system for our needs?
July 2005 A.Fabich, CERN AB-ATB 9
Operation Scenario Single pulse experiment
About 150 extractions (integrated intensity < 3 1015 protons) One extraction of up to 3*1013 protons @ 24 GeV every ~30 minutes
Proton beam properties change from pulse to pulse
Solenoid temperatureProton intensity
B-field
and repeat
July 2005 A.Fabich, CERN AB-ATB 10
High Field Pulsed Solenoid
collecting device for mesons 80 K Operation to optimize for costs Not superconducting! 15 T with 4.5 MW Pulsed Power 15 cm warm bore (L=1m) 4.5 ton
Pet
er T
itus,
MIT• power cycle 15 seconds• Cooling cycle of solenoid limits to a minimum repetition time of 30 minutes between two pulses!
July 2005 A.Fabich, CERN AB-ATB 11
Radiation environment
Simulated neutron flux at r = 0.6 m Radially: 10-3 n/cm2/p.o.t. Forward: 1.2 x 10-3 n/cm2/p.o.t. Backwards: 1.6 x 10-3 n/cm2/p.o.t.Diagnostics are located at r = 0.03 cm → 400x
A test in ISOLDE (1.4 GeV) with a total of 4*1015 p.o.t. resulted in 3 kGy. At MERIT we expect more like 50-100 kGy.
July 2005 A.Fabich, CERN AB-ATB 12
Diagnostic specifications
Area of “view”: 4 x 8 cm x 8 cm = 250 cm2
Spatial resolution: ~ 0.2 mm Shutter time: ~1 micro-second Frame rate: 10 kHz to 1 MHz Record time: up to 1 second
Radiation hard Exposable to 15-Tesla field, < 50 T/m