Conventional Neutrino Beam at K2K and JHF

K2K Neutrino Beamfor KEK Beam Channel Groupand K2K Beam Monitor Group

JHF Neutrino Beamfor JHFnu Working Group

T.KobayashiIPNS,KEK

May 29, 2001Fact01 WG3

Neutrino Beam Production(conventional method)

ProtonBeam

TargetFocusingDevices

Decay Pipe

Beam Dump

+

Pure beam (~99%)

e ( 1%) from e chain and K decay(Ke3)/ can be switched by flipping polarity of focusing device

General Requirements on Conventional Neutrino Beam

(for long baseline experiments)

• Fast Extraction w/ precise beam timing info.

– to identify event from acc. at far detectorKicker magnetGPS time stamp ( t~200ns)

• As high intensity as possibleHigh transmittance beam transportElectromagnetic Horn

• Precise directioning (<3mrad)GPS survey

• Stable

Neutrino Spectra and Radial Distributions at 250km (MC)

Change in flux/spectrum < 3mr(750m) @ SK negligible

0 1 2 3Radius (km)

x105

12

8

4

3mradSK

106

107

108

109

0 1 2 3 4 5P (GeV/c)

Neut

rino

flux i

n ar

bitra

ry u

nits

On axis flux

Off axis flux

General Layout of the KEK Neutrino Beam Facility

The Apparatus for the Longest Shooting Game

Single turn fast extraction

9bunches/1.1 sec spill/2.2s

•Protons@Entrance

6.3x1012 protons/2.2s

•Protons @ Horn

5.4x1012 protons/2.2s

~85% Transmission

•Some Magnets are replaced by larger bore ones.

•Beam Monitors are set in vacuum.

Proton Beam Line(400m Long, 114 Magnets)

K2K Electromagnetic Horns

Tandem horn system1st Horn : Outer diameter= 0.62m, Length= 2.42m

Built- in production target (<φ30mm)High magnetic field (5 Tesla)

2nd Horn : Outer diameter= 1.65m, Length= 2.76mThin inner conductor (thickness 3mm)Large magnetic volume

Operation current 250kAmp at both hornsHigh pulsed current 2.5ms width, 2.18s cycleTotal Joule’s heat=7740 kcal/h

Top View

Side View

Electromagnetic Horns

0

2

4

6

8

0 1 2 3 4 E (GeV)

Neu

trin

o Fl

ux (a

rb. u

nit)

0kA

250kA

x20

(MC)

2001/5/8yamanoi

0.0E+00

1.0E+06

2.0E+06

3.0E+06

4.0E+06

5.0E+06

6.0E+06

Feb-

99M

ar-9

9

Apr-

99M

ay-9

9

Jun-

99Ju

l-99

Aug-

99

Sep-

99O

ct-9

9

Nov-

99De

c-99

Jan-

00

Feb-

00M

ar-0

0

Apr-

00M

ay-0

0

Jun-

00Ju

l-00

Aug-

00

Sep-

00O

ct-0

0

Nov-

00De

c-00

Jan-

01

Feb-

01M

ar-0

1

Apr-

01M

ay-0

1

Jun-

01Ju

l-01

Aug-

01

1st Horn(#07

1st Horn(#04

1st Horn(#0

1st Horn(#0

1st Horn(#0 ->#05

2nd Horn #0

2nd Horn #02

2nd Horn #03

'99 run

'00 run

3

'01 run

Horizontal = 1.2m

Vertical = 0.7m

positioning precision = 5x10-6

Positioning of SK and KEK

(1) Procedure

Local GPS at KEK Long Baseline GPS btwn KEK and Kamioka Local GPS in Kamioka Optical Survey in the Mozumi Mine(SK)

(2) Precision of Positioning

GPS: Nominal error:

=10-6xD + b, b~5-10mm, D=250km= 0.3m(KH)

Optical Survey: the Error of Closure:

traverse=0.9m(SK)

leveling =0.4m(SK)

Summary

(1) Beam Line Construction & Operation

(2) Positioning of SK and KEK

(3) Beam Line Alignment to the SK Direction

(4) Beam Control

0.02 mrad in Hor.0.05 mrad in Ver.

Horizontal = 1.2m

Vertical = 0.7m

positioning precision = 5x10-6

Experimetal Requirement was 1 mrad

0.03 mrad in Hor.0.06 mrad in Ver.

Stably Running since 1999.6

Established the Tuning of Beam Direction

Monitoring the Beam Line Direction

in finite time range

Decay Volume and Muon Monitor

-beam profilemeasured by muon monitor(Segmented PPIC & SSD)

Measurement/Control Accuracy is <0.1 mr.Requested Stability is 1mr.

5

10

15

20

25

30

35

0 200 400 600 800 1000

0 200 400 600 800 1000

5

10

15

20

25

30

35

0

50

100

150

200

250

300

350

5 10 15 20 25 30 35

0

25

50

75

100

125

150

175

200

5 10 15 20 25 30 35

Muon Centroid Horizontal (5cm/ch)

Muon Centroid Vertical (5cm/ch)

-0.5mrad +0.5mrad

Num

ber

of P

ulse

Num

ber

of P

ulse

-0.5mrad +0.5mrad

33

Stability of Muon Profile Center @ Muon Monitor

Fast (spill-by-spill) but indirect monitor

Stable within 1mrad

1mrad

1mrad

Jun‘99

Jun‘00

Nov‘99

Jan‘00

Feb‘00

Mar‘00

May‘00

01234567

Jan/99 Apr/99 Jul/99 Oct/99 Jan/00 Apr/00 Jul/00 Oct/00 Jan/01 Apr/01 Jul/01

Pro

tons

/Pul

se (

1012

)

Date

0

5

10

15

20

25

30

35

40

45

50A

ccum

ulat

ed P

OT

(10

18)

Delivered Protons on Target (POT)

Neutrino Beam @ JHF

∆m2=1.6~4x10-3eV2 from atm. ν at SK• Eν~1GeV

~1GeV νννν beamKamioka

JAERI(Tokaimura)～～～～1 MW 50 GeV PS

Super-K: 50 ktonWater Cherenkov

“Super” conventional low energy beam

6

Horns Decay PipeFar Det.

Wide Band Beam

Narrow Band Beam

Off Axis Beam

Horn10

2horns

momentum selected

Three Beams

High int. narrow band beamMore HE tail than NBBHard to tune E

IntenseWide sensitivity in m2

BG from HE tailSyst. err from spectrum extrapolation

Less HE tailLess sys err from spectrum

“counting experiment”Easy to tune E

9

JHF

Construction2001 2006

JAERI@Tokai-mura(60km N.E. of KEK)

(Approved in Dec.2000)

11

3.85

4.90

3.60

09007300

428005.43500

5005000

000

000

500

3000

000

6000

4000

5743

400

824

459

343 6

50GeV PS & Extraction

Intensity 3.3x1014 proton/pulse (ppp)Repetition rate 0.292 HzPower 0.77 MW (2.64 MJ/pulse)Single turn fast extraction (~5.23 sec spill)8 bunches/spill (2 out of 10buckets empty)Kicked 4.9 inside PS ringStraight matching section 43 m

(conventional magnets)

PS ring

Neutrino line

12

Arc & Final focus

Bend ~85 to SK direction

50GeV, 110 m curvatureNeed super con. mag.

Typical magnet parameters~4T, ~4m long(to be decided)

need 15~20 dipole magnets

Proton directed 1.25 downward

R=110m

Final focus

13

Target StationNBB

OABWBB

1.25

Accommodate 3 beam optionsNo free space for maintenance(to reduce shield)

Horn replacement from ceiling

5.4m

3m

Fe

Concrete

# of CC events of various beams

WBB WBB

LE1.5LE2LE3 OA3

OA2OA1

WBB:5200 CC int./22.5kt/yrNBB: 620 CC int./22.5kt/yr (2GeV/c tune)OAB: 2200 CC int./22.5kt/yr (2degree)

Summary K2K neutrino beam

First neutrino beam facility for long baseline neutrino experimentProton beam transport >85% eff.Tandem horns with 250kA pulsed current operationLife time of horns is ~6 M excitationsBeam direction

GPS survey ±20µrad(H), ±50µrad(V) in KEKBeam control : ±30µrad(H), ±60µrad(V) (short term)

<±1mrad for whole running periodSatisfy experimental requirement

~4.6x1019POT has been delivered since 1999.

JHF neutrino beam3.3x1014ppp, 0.77MW ~1021POT/yrTechnical design of facility going onUse super conducting magnets3 beam configurations

WBB 5200 νµCC int/22.5kt/yrNBB 620 νµCC int/22.5kt/yrOAB 2200 νµCC int/22.5kt/yr

Tunable peak energyAim to complete at the same time as acc.(2007)

2000/10/7 8

pH control & CorrosionpH7.4~8.5Floating ion: [Al(H2O)2(OH)4]-

Conductance 10 S/cmSolution rate 0.4mg/cm2 hSelf healingCorrosion Alumite growth

(~5 m)Neutralize of cooling water every 2 weeks pH6~7 is a target condition

pH-Solution rate, Conductance

0.001

0.01

0.1

1

10

100

1000

10000

2 3 4 5 6 7 8 9 0 2 3 4

pH

Solu

tion

rate

[m

g/m

2h]

1.0E-10

1.0E-08

1.0E-06

1.0E-04

1.0E-02

1.0E+00

1.0E+02

1.0E+04

Cond

ucta

nce

K [S

/cm

]

Coo lin g wate rCoo lin g wate rCoo lin g wate rCoo lin g wate r

Dr in kable wate rDr in kable wate rDr in kable wate rDr in kable wate r

Ion e limin at ionIon e limin at ionIon e limin at ionIon e limin at ion

wate r P 4wate r P 4wate r P 4wate r P 4

Oct.99Aug.00

2000/10/7 16

Incident proton beam and pulsed currentThe current of 2nd horn was delayed 100 s for synchronizing with the incident beam.

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111110000000000 00000.....55555 mmmmmsssss/////DDDDDIIIIIVVVVV