The NuMI Neutrino Beam

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26 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

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

1


The NuMI Neutrino Beam



I. Status of 0.4MW Beam


II. Potential for 1.6MW


II. What’s it Good For?

Sacha E. Kopp,

University of Texas


Austin


for the

NuMI/MINOS Collaboration

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

2


NuMI has 400kW

primary proton beam


120 GeV


8.67
m
獥挠獰楬l


ㄮ㤠獥挠r数e牡re

MINOS

(Fermilab to Minnesota)

L = 730 km


Beam Axis 3.32
o

into the ground at
FNAL, exits at
Canadian border.


2
o

off
-
axis in
southern Canada or
northern Wisconsin
(
L

= 530


950 km)

(12 km)

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

3

NuMI Tunnel

105 m

Soil

Dolomite

rock


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


Near Detector on beam axis


Also access passageway available for near off
-
axis detector


Beamline passes through 3 acquifers

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

4

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 intensity

e
h
,
e
v

~ 25
p

mm
-
mrad measured in MI (design for 40
p
)

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


10
-
4

)

»
Potential routes to improve proton intensity include batch ‘stacking’

Plan for 2
-
4


larger emittances.

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

5

Improved Extraction Channel


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

Old Design

New Design

figures courtesy S.Childress

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

6

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)

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

7

NuMI Target Hall

Horn+Module in transit



Stripline


Concrete Cover



“Carriage”
-

Module


Support Beams


Horn Shielding Module


Horn



Steel Shielding


Air Cooling Passage

Concrete Shielding

Temporary Stackup


of removed shielding

Steel 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

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

8

NuMI Production Target

FNAL design team


J.Hylen, K.Anderson

FNAL beam test


J.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

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

9

Prototype Target Test


Teeth show no


damage after


7x10
17

protons



3x10
5

pulses


2x10
18

protons/mm
2


(~ 1 NuMI week )



Max. stress pulses:


1x10
13
/pulse


0.2 mm RMS spot


NuMI Design:


4x10
13
/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?

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

10

Target and Horn Modules

Water tank

Stripline

Remote

Stripline

Clamp

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

figure courtesy E.Villegas

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

11

Stripline and Remote Connections

Stripline shielding block stays with
module







Remote clamp allows horn
disconnection from module

(for horn replacement)



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

12

Target/Horn Module Carriages

Carriages:


Cross
-
beams that


modules rest on


130
o
C

15
o
C

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

13

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
Jun-
97
Jul-
97
Aug-
97
Aug-
97
Sep-
97
Oct-
97
Nov-
97
Dec-
97
Jan-
98
Feb-
98
Mar-
98
Date
(Runs nights and weekends only)
pulses at 200 kA
Test Power Supply,
0.85 ms pulse
Production Power Supply,
2.7 ms pulse, 205 kA peak
Water line fixture fracture
S.Kopp: NuFact ’02, Imperial College, London

14

Design & Procurement Status

Horn 2

Outer conductor:


is currently being machined


Inner conductor:


Welding parameters being



developed on test pieces


Have done 1
st

two welds



on real horn


Finish assembly horn 2


~ end of year


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

15

Horn Field Measurement

Main horn field between conductors

Field between conductors:




1/
r

as expected


very symmetrical


agrees within meas. error with current

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

16

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 small

that no correction should need to be put

into the Monte Carlo.




Measurement with probe

moving 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)

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

17

NuMI Horn 1

Vibration Measurement on Horn Bell Endcap

6
m
m

55
m
m

(ANSYS gives 71
m
m)

1.17 kHz (ANSYS 1.19 kHz)

DATA

Linear Model

DATA

Linear Model

2 sec

0.03 sec

NB: proton intensity upgrade is


non
-
trivial if it requires faster


rep
-
rate.

figures courtesy J. Hylen

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

18

TBM in Target Hall (May 2001)

TBM
-

front

TBM
-

back

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

19

NuMI Decay Tunnel
-

July 2001

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

20

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)

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

21

Sample Pipe / Shielding View

concrete radiation
shielding, density
2.1 g/cm
3

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 ~ 50
o
C


May be expensive to upgrade for

4 beam intensity.

Target hall to absorber
secondary access

Relative

centers

vary along

length

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

22

Beam Absorber

Egress path


Absorber core

»
8 aluminum plates


30.5 x 129.5 x 129.5 cm
3

»
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?

Concret
e

blocks

Absorber core

Steel
blocks

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

23

Summary of NuMI Upgradeability

table courtesy N. Grossman

Item
4E13 ppp
(1.9sec rep)
8E13 ppp
(1.9sec rep)
1.5 E14 ppp
(1.9sec rep)
Radiation Issues
OK
seal 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
OK
New Target and
Cooling ($750K)
Horns and Cooling
OK
OK
OK
Target Chase Cooling and
Shielding
OK
cooling for
stripline? ($500K)
Cooling for whole
chase ($5 million)
Hadron Absorber Cooling
OK
probably OK
Additional cooling
needed ($1 million)
Decay pipe cooling
OK
don't know
need cooling ($1
million??)
Additional Cooling ponds
may need more
may need ($150K)
will need ($400k)
Total
$ 1 million +??
$9 million
S.Kopp: NuFact ’02, Imperial College, London

24

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 Beam

NuMI LE Beam

figures courtesy M.Messier

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

25

Instrinsic
n
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
m

decays for new exp’t?

All
n
e

backgrounds

From
K

decays

figures courtesy M.Messier, R.Zwaska

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

26

n
e

Backgrounds Summary


Plot assumes |U
e3
|
2
=0.01,
D
m
2
=3.0

10
-
3

eV
2
.


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
n
e
.

figure courtesy M.Messier

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

27

Comparison of Exp’ts


Assume
D
m
2

= 3.0


10
-
3

eV
2
, sin
2
q
13
=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/yr

712 km baseline

JHF Phase I,

5yrs @ 0.77MW

295 km baseline

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

28

Interpretation of PhaseI Results


Interpretation of
n
m

n
e

observation


Observation would be strengthened by antineutrino running.

d

Sign(
D
m
2
)

d

Sign(
D
m
2
)

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

29

Antineutrino Running


Can we disentangle mass heirarchy and CP violation?

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

30

Compare Baselines


950km

712 km

295 km

sin
2
q
13
=0.02

sin
2
q
13
=0.05

D
m
2
>0

D
m
2
<0

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

31

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)

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

32

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