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 c

m

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

Pete

r Titu

s, M

IT• 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