Upload
pierce-franklin
View
234
Download
5
Tags:
Embed Size (px)
Citation preview
1
MINOS/NuMI projects
●Introduction to kingdom MINOS/NuMI ●Physics goals of MINOS ●Kingdom built
●NuMI beamline ●MINOS detectors
●Running the kingdom - data taking● Atmospheric● Beam
● Summary
Hai ZhengHai ZhengCaltechCaltechMINOSMINOS
King Minos holding the sceptre that Zeus himself gave him
2
Near Detector980 Tons measure the beam energy spectrumFermilab, IL
Far Detector5.4 kTons measure the oscillationSoudan, MN
Introduction MINOS is an accelerator-based Long-Baseline
neutrino experiment to study oscillationwith
high statistics ’s are generated at Fermilab from 120 GeV protons and delivered by the NuMI beamline
Both detectors have magnetic fields:
first large underground detectors to identify - and + separately
Detector 2
Detector 1 735 km
3
MINOS Physics goals
m223
disappearance :– Confirm oscillations
– Precise Measurement of sin2(223) & m223 :
● Poscillationsin2(223)sin2(1.27m223 L /E)
● Goal: 1 precision 3-5%
Search fore appearance:
• Might be able to observe e appearance
Atmospheric measurements and capable of first direct observation of separated atmospheric ν and ν oscillations
P(esin2(213)sin2(23)sin2(1.27m2 L/E)
4
MINOS sensitivity for m2 and sin22
• location & depth of the signal yield m2 & sin22measurements• be able to rule out non-oscillation models• precision improves with additional protons
For m2 = 0.0025eV2, sin22 = 1.0
Oscillation measurement: Compare the observed energy spectrum at the far detector to the expected un-oscillated spectrum calculated from the near detector measurement
Left: the ratios of oscillated to un-oscillated spectrum
signal
5
MINOS Sensitivity to e Appearance
For m2 = 0.0025 eV2, sin2 213= 0.067
Assuming 25 x 1020 protons on target
Background dominated by Neutral current interactions
(+ some intrinsic beame’s)
Energy Spectrum
m2 = 0.0025 eV2
detection of e at m2atm
evidence for non-zero 13
Can improve 90% CLby a factor of ~2 with higher proton intensity
6
NuMI – MINOSNuMI – MINOS @ Fermilab @ Fermilab
Tevatron
MainInjector
Booster
TargetEnclosure
DecayEnclosure
MINOSNear
Detector
To Soudan M
ine
NuMI BeamlineNuMI BeamlineTo transport protons to the To transport protons to the target & generate the target & generate the beam beam Designed for up to 4 x 10Designed for up to 4 x 101313 protons/pulseprotons/pulse
Earlier commissioning:Earlier commissioning:●Delivered low proton intensity on the Delivered low proton intensity on the target with low repetition ratetarget with low repetition rate
February 18-March 23, 2005:February 18-March 23, 2005:•Varied Varied energy spectra by moving the energy spectra by moving the targettarget•MI was operating w/ high proton MI was operating w/ high proton intensityintensity
•reached up to 2.5reached up to 2.5 x 10x 101313 ppp ppp•Repetition rate was increased to Repetition rate was increased to nominal rate of 0.5 Hznominal rate of 0.5 Hz
Main Injector (MI) Main Injector (MI) goal for this yeargoal for this yearaccelerate 2.5 x 10accelerate 2.5 x 101313 protons protons every 2 seconds to 120 GeV every 2 seconds to 120 GeV ~8 ~8 sec spill,sec spill, 0.25MW 0.25MW
7
NuMI Beamline Layout & components
Components
Layout• Aimed downwards at 58 mrad toward the Soudan mine
• Protons hit segmented graphite target & charged hadron beam is focused with two magnetic horns
• 675m long steel vacuum decay pipe
• Hadron monitor and hadron absorber downstream of decay pipe
• 200m rock upstream of Near Detector for muon absorption & muon monitors
207 m
ProtonsProtons
π, K
8
Horn 2
• 6.4 x 15 mm2
• ~1 m long: 2 interaction lengths
Graphite target w/ water cooling tube
target vessel (vacuum) with beryllium window
Target and Horns
Back face of horn 2Assembled horn 1
• Parabolic shape of inner horns gives focusing• 200 kA peak current• 3 Tesla peak field• 1.87 sec repetition rate(designed)
9
Target Water Leak• Water-cooled graphite fins sit inside a vacuum chamber
• Target was filled with water in March, investigated• Leak self-repaired, target back in, operations resumed.
–Leak reappeared, now back pressuring helium–2nd target will be ready in Aug.–Building another spare target –Interesting facts learned:
• Beam scans across the target confirm extra material (proton radiography)
Attenuation through water?
Water Filling Target Can Water Being Pumped
from Target Can
Multiple scattering
through H2Obaffle baffletarget
baffle baffle
10
• Can change the energy spectrum by moving the target (shown in plots), or by moving horn 2, but needs more work
NuMI eam Running
Target is inside horn 1 (LE)2.5 x 1020 protons/year produces ~1600 CC events in FD assuming no-oscillation
Energy spectra for different target positions
Data acquisition was stopped because of water leak in the target
11
60-plane ‘micro - MINOS’ -- has taken data at T7 & T11 test beam lines at CERN during 2001, 2002, 2003
MC expectation
Calibration Detector
12
Far Detector
8m octagonal tracking Calorimeter486 planes (5.4 kTon total)2 super modules(SM) : 15 m long eachToroidal B-field: 1.3 T at r = 2m Veto shield for cosmic’s Completed in July 2003 Recording cosmic ray muons since 2002
Plane with scintillators installedCompleted Far
Detector
13
Near Detector at Fermilab
Completed Near Detector
Partial plane Full plane
Same basic design as the far detector but smaller
• 282 single steel planes• 980 Tons
Combination of partially & fully instrumented planes
● Calorimeter (120 planes) is partially instrumented except for 1/5 of planes with full coverage
● Spectrometer (162 planes) has only every 5th plane instrumented
Plane assembly was completed in August 2004
14
MINOS Running• To ensure smooth running of the long baseline neutrino experiment,
we need good coordination and monitoring between near and far sites
• Experts on-call• Fermilab main control room – physicist shifters• Soudan control room – now mainly mine crew, not 24/7
• Collaboration with Fermilab accelerator division on different projects for better beam quality and high intensity beam
• NuMI beam monitoring and instruments• MI/Booster upgrade and improvements, such as:
• damper system to reduce oscillation amplitude• cogging to synchronize Booster extraction with MI with
multi-batch operation• and many more ...
• Proton intensity, such as barrier RF stacking and slip stacking• Overlapping collaborators with experiments such as MIPP,
MINERA, with broader scope of neutrino physics in mind
15
Atmospheric •Since completion in August 2003 the Far
Det has been taking atmospheric neutrino data.
•Beam switched on 1st March 2005 at which point the Far Detector had collected 420 days of physics quality data, excellent for a detector still in commissioning stage.
•Total of 6.18 kton-years of data suitable for atmospheric neutrino studies, c.f. Soudan 2's 7.36 kton-years
•Will still take atmospheric neutrino data during beam running.
•Publication coming soon, stay tuned!
MINOS PRELIMINARY
DATA
V vs Z
ADC vs Z
Time vs Z(2.4 ns)
U vs Z
stopping
with
veto hits
Example EventsFully Contained Partially Contained
Downward Going
ν induced μPartially ContainedUpward Going
17
Accumulating beam data at both detectors !!!
18
Incoming Direction for Near Detector Neutrinos
• Zenith and azimuth show point of origin of the neutrinos within spill time
• Beam points downward 3.3 degrees, expect peak at cosθ = 0.06
• Beam also points west of north, expect peak at 156 degrees
• Neutrinos definitely coming from the beam! S
EW180
90270θ
Near Det.
Thousands of 's already!
19
2.51012protons/1.6s spill
Separation of two categories of interactions:
• Interaction inside of the near detector: Fully contained event
• from interaction in the rocks surround the near detector: Rock this one goes through the whole detector
Interactions of the beam in Near Detector
Beam direction
MINOS preliminaryBack view
v
u
u view
v view
20
First beam event at Far Detector: Rock
Event seen in both SuperModule1 & SuperModule2Charge identification from curvature : -Detected momentum ~12 GeV from curvature & the # of planes the track passed
Entrance point
x
y
B
Beam direction
MINOS preliminary
u view
v view
21
First Fully Contained Event in Far Detector
Beam direction
Showering event(Neutral Current candidate?)
MINOS preliminary
discovered by our Greek collaborator at the end of March
22
More Far Detector Events
Beam direction
Charged current quasi-elastic scattering candidate n p?
MINOS preliminary
23
More Far Detector Events
MINOS preliminary
Freshly produced in May
Another Charged Current
Candidate
24
More Far Detector Events
MINOS preliminary
Freshly produced in May, from the same run
Showering Event (
e Candidate?)
25
Summary
●NuMI beamline is completed and commissioned●2.5x1013 protons/spill & 0.5 Hz repetition rate have been achieved separately
●Water leak in target investigated and under control●MINOS detectors are completed & operating
●acquiring atmospheric ’s with over 90% live time, first publication coming out soon!
●beam data-taking at both detectors•precise measurement of m2 and sin22•search for non-zero by detectinge appearance
●Minoans have been working hard and eagerly await the final judgment
`Thus I descended from the first circle down into the second, which girdles less space, and so much more woe that it goads to wailing. There abides Minos horribly, and snarls; he examines the sins at the entrance; he judges, and he sends according as he entwines himself.'
Dante Alighieri - Divina Commedia
Gustave Dore