s.kopp: nufact ’02, imperial college, london 1 the numi neutrino beam i. status of 0.4mw beam ii....

S.Kopp: NuFact ’02, Imperial College, London 1

The NuMI Neutrino BeamI. Status of 0.4MW BeamII. Potential for 1.6MWII. What’s it Good For?

Sacha E. Kopp,University of Texas – Austin

for the NuMI/MINOS Collaboration


•NuMI has 400kW primary proton beam 120 GeV 8.67 sec spill 1.9 sec rep rate

MINOS (Fermilab to Minnesota)

L = 730 km

•Beam Axis 3.32o into the ground at FNAL, exits at Canadian border.•2o off-axis in southern Canada or northern Wisconsin (L = 530 – 950 km)

(12 km)


NuMI Tunnel105 m

Soil Dolomiterock

• Decay volume 2m Ø, 675 m long (10 GeV )

• Near Detector on beam axis

• Also access passageway available for near off-axis detector

• Beamline passes through 3 acquifers


NuMI Extracted Proton Beam

• Passes through acquifers»10-4 losses throughout beamline (magnets activated to 200mrem/hr).»10-6 losses in ‘transition’ soil-rock region (groundwater activation).

• Two major bends»150 mrad bend downward from Main Injector»100 mrad bend upward toward Soudan

• Want to be even more conservative in design»First operation of Main Injector in multi-batch mode»Emittance growth with intensityh, v ~ 25 mm-mrad measured in MI (design for 40)

l, ~ 0.5-0.6 eV-sec measured in MI (design for 1 eV-sec) (p/p ~ 5 10-4 )

»Potential routes to improve proton intensity include batch ‘stacking’Plan for 2-4 larger emittances.


Improved Extraction Channel

• Added $0.5M in focusing in 40m drift region through soil-rock interface.

Old Design New Design

figures courtesy S.Childress


Target Hall

Beamline Component Positioning Modules

Two Types of Magnetic Focusing Horns

Pion Production Target (plus readout of target, vacuum pump)

Baffle to protect horn from beam accidents

Target Hall Radiation Shielding Radioactivated component work cell

Alternate Horn Positions(eg: for off-axis exp’t)


NuMI Target Hall

Horn+Module in transit

Stripline Concrete Cover

“Carriage” - Module Support Beams Horn Shielding Module Horn

Steel Shielding Air Cooling PassageConcrete Shielding

Temporary Stackup of removed shieldingSteel from module middle Concrete from over horn

Beam passageway (chase) is 1.2 m wide x 1.3 high, forced-air-cooled

• Shielding protects

groundwater below

personnel above

• Air volume sealed, recirculated


NuMI Production Target

FNAL design teamJ.Hylen, K.Anderson

FNAL beam testJ.Morgan, H.Le, Alex Kulik, P. Lucas, G. Koizumi

IHEP Protvino design team: V.Garkusha, V.Zarucheisky F.Novoskoltsev, S.Filippov, A.Ryabov, P.Galkin, V.Gres, V.Gurov, V.Lapygin, A.Shalunov, A.Abramov, N.Galyaev, A.Kharlamov, E.Lomakin, V.Zapolsky Target read-out

Budal mode


Prototype Target Test

•Teeth show no damage after 7x1017 protons

•3x105 pulses•2x1018 protons/mm2

(~ 1 NuMI week )

•Max. stress pulses: 1x1013/pulse 0.2 mm RMS spot

NuMI Design: 4x1013/pulse 0.9 mm spot, 23MPa stress (cf 100MPa limit)

•If go to 1.6MW beam, require spot size 2.0mm-Maintains target temperature-Maintains target stress-Long-term radiation damage?


Target and Horn Modules

Water tank

Stripline

RemoteStriplineClamp

Baffle

Target

Target/Baffle Module Horn 1 Module

Horn 1

25 cm wide, 2 m deep Steel endwalls with positioning, water, electric feedthroughs

Motor drives for transverse and vertical motion of carrier relative to module

Carrier Target moves 2.5 m along beam

figure courtesy E.Villegas


Stripline and Remote Connections

Stripline shielding block stays with module

Remote clamp allows horn disconnection from module (for horn replacement)


Target/Horn Module Carriages

Carriages: Cross-beams that modules rest on

130oC

15oC


Horn 1 Prototype

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

Mar-97

Apr-97

May-97

J un-97

J ul-97

Aug-97

Aug-97

Sep-97

Oct-97

Nov-97

Dec-97

J an-98

Feb-98

Mar-98

Date(Runs nights and weekends only)

puls

es a

t 20

0 kA

Test Power Supply, 0.85 ms pulse

Production Power Supply, 2.7 ms pulse, 205 kA peak

Wat

er li

ne fi

xtur

e fr

actu

re


Design & Procurement StatusHorn 2

Outer conductor: is currently being machined

Inner conductor: Welding parameters being developed on test pieces Have done 1st two welds

on real horn

Finish assembly horn 2 ~ end of year


Horn Field MeasurementMain horn field between conductors

Field between conductors: 1/r as expected very symmetrical agrees within meas. error with current


Horn Field Measurement in ‘field-free’ region through center of horn

Error or fringe field in “field-free”region down center of horn is so smallthat no correction should need to be putinto the Monte Carlo.

Measurement with probemoving along horn axis

2% F/N criterion on flux in M.E. beam (approximately scaled to 0.85 ms test pulse from 2.6 ms operational pulse)


NuMI Horn 1Vibration Measurement on Horn Bell Endcap

6 m

55 m

(ANSYS gives 71 m)

1.17 kHz (ANSYS 1.19 kHz)

DATA

Linear Model

DATA

Linear Model

2 sec0.03 sec NB: proton intensity upgrade is non-trivial if it requires faster rep-rate.

figures courtesy J. Hylen


TBM in Target Hall (May 2001)

TBM - front

TBM - back


NuMI Decay Tunnel - July 2001


Decay Pipe

• 2m Ø steel cans, 1 cm wall.

• Reinforced by 4” rings @ 20 ft.

• Decay volume evacuated to ~0.1-1.0 Torr

• Helium-filling is a backup

• Complete decay pipe now in place, welded, inspected.

• Dual entrance window»Inner 1m Ø = 1.5mm Al»Outer 2m Ø = 1.0 cm Fe»Should readily handle increase in beam power (currently designed for beam accident)


Sample Pipe / Shielding View

concrete radiation shielding, density 2.1 g/cm3

Decay pipe • Decay region power deposition» 63 kW in 1 cm thick steel

decay pipe» 52 kW in shielding concrete» Peak deposition in the steel is

~360 W/m» Drops to 20 W/m (at ~610 m)

• Heat removed by water-cooling» 12 plastic-coated copper lines» Final temperature ~ 50oC

• May be expensive to upgrade for 4 beam intensity.

Target hall to absorber secondary access

Relative centers vary along length


Beam Absorber

Egress path

• Absorber core» 8 aluminum plates 30.5 x 129.5 x 129.5 cm3

» dual water-cooling paths» 8 kW peak power in one module

(normal beam conditions)» followed by 10 plates of steel,

each 23.2 cm thick.

• Total power into Absorber: 60 kW

(400 kW beam power if accident)

• Water-cooled Aluminum easily can accommodate increased beam power from proton upgrad

• Steel is more problematic – require adding water cooling?

Concrete

blocks

Absorber coreSteel blocks


Summary of NuMI Upgradeability

table courtesy N. Grossman

Item4E13 ppp

(1.9sec rep)8E13 ppp

(1.9sec rep)1.5 E14 ppp (1.9sec rep)

Radiation Issues OKseal chase more

($250K)seal chase more

($500K)

Collimators may need

very likely need (3@ $60K=

$180K)

very likely need (3@ $60K=

$180K)Primary Beam and Power Supplies OK OK OK

Target and Target Cooling OK OKNew Target and Cooling ($750K)

Horns and Cooling OK OK OKTarget Chase Cooling and Shielding OK

cooling for stripline? ($500K)

Cooling for whole chase ($5 million)

Hadron Absorber Cooling OK probably OKAdditional cooling

needed ($1 million)

Decay pipe cooling OK don't knowneed cooling ($1

million??) Additional Cooling ponds may need more may need ($150K) will need ($400k)Total $ 1 million +?? $9 million


Off-Axis case for Existing NuMI

• Plots assume current neutrino target, horns.

• Variable energy beam can help move peaks dynamically

• Antineutrino running takes factor 3 hit in rate

NuMI ME BeamNuMI ME BeamNuMI LE BeamNuMI LE Beam

figures courtesy M.Messier


Instrinsic e in Off-axis Beam

• NuMI decay tube is quite long (675m)

• Good news: bckgd uncertainty lower in off-axis case.

• Back-fill last ~200m (water?) to reduce decays for new exp’t?

All e backgrounds

From K decays

figures courtesy M.Messier, R.Zwaska


e Backgrounds Summary

• Plot assumes |Ue3|2=0.01, m2=3.010-3 eV2.

• NC is all interactions before any identification cuts.

• Detector design requires >10 reduction in NC events?

• For rest of discussion, assume NC reduced to level of beam e.

figure courtesy M.Messier


Comparison of Exp’ts

• Assume m2 = 3.0 10-3 eV2, sin213=0.1,

• For NuMI, assume a 20kt detector, 85% fid.vol, analysis of low-Z calorimeter

• NuMI can make up for lower proton power, longer baseline because of higher neutrino, pion, cross sections.

NuMI-MINOS, 2 yrs @ 8E20 POT

NuMI Off-Axis,5yrs @ 4E20 POT/yr712 km baseline

JHF Phase I,5yrs @ 0.77MW295 km baseline


Interpretation of PhaseI Results

• Interpretation of e observation

• Observation would be strengthened by antineutrino running.

Sign(m2)

Sign(m2)


Antineutrino Running

• Can we disentangle mass heirarchy and CP violation?


Compare Baselines

950km950km712 km712 km295 km295 km

sin213=0.02sin213=0.02

sin213=0.05sin213=0.05

m2>0

m2<0

m2>0

m2<0


More Protons for NuMI

• Original baseline 4E13 protons/spill, 4E20/yr.

• Present performance of Booster is 4.5-5.0E12protons/batch (5 batches per MI extraction)

• Possible paths to improvement»Get all 6 Booster batches (post-collider)»Multi-filling of MI (‘stacking’)»Reduce MI acceleration time (requires new RF)

• Potential proton source upgrades -- $200M+»16 GeV ‘proton driver’ »8 GeV proton LINAC (R&D for Linear Collider)


Summary

• NuMI is substantial investment in US HEP program

• Design is flexible to permit variations, upgrades

• NuMI off-axis exp’t has complementary capabilities to JHF

• Real attack of CP violation requires substantial extensions to existing plans -- JHF-II and NuMI-II»4MW proton beam for JHF, 1.6MW for NuMI»HyperKamiokande, NuMI would have …?

• Lots more extensive documentation:»Letter of Intent to Build an Off-Axis Detector for NuMI,

www-numi.fnal.gov/new_initiatives/new_initiatives.html»“The Proton Driver Design Study”, FERMILAB-TM-2136» G.W.Foster, W. Chou, E. Malamud, FERMILAB-TM2169.»“Physics at FNAL with Stronger Proton Sources”, FERMILAB-FN-720

s.kopp: nufact ’02, imperial college, london 1 the numi neutrino beam i. status of 0.4mw beam ii....

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