Calibration MINOS and Minerva

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Calibration (MINOS and Minerva)
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MINOS Calibration Requirements

• Studies were done of the calibration necessary to
  extract Dm2 and sin22q from nm CC events with
  10 precision
• Energy calibration ND vs. FD consistent to 2
• Absolute energy 5

En,cc Ehad_shower Em
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Energy reconstruction in MINOS

• ADC ? light
• PMT gain singles data or low-light runs with
  light-injection (LI) system
• Gain changes LI drift-point calibration
• Linearity of PMTs readout LI system charge
  injection (for PIN)
• Electronics calibration (pedestals linearity)
• Light ? MIP Units
• Attenuation correction, from production mapping
  of scintillator
• Strip-to-strip calibration with cosmic muons
• Path-length corrections to establish MIP energy
  scale
• Near-far differences must be corrected with
  cosmic muons
• MIP Units ? Hadron energy
• From the calibration detector (1m x 1m
  replica of the MINOS detector)

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MINOS Light Injection System

• The MINOS light injection system has 4 main
  purposes
• To linearize the response of the PMT /
  electronics
• To monitor short timescale drifting of the
  response
• To accurately determine the position of the
  single photoelectron peak
• Is everything plugged in?

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LI system Basics
Light from ultra-violet LEDs illuminates up to 70
fibers in a pulser box. Light is transported to
the light injection manifold where it is
dispersed uniformly over 8-10 WLS fibers.
Scintillator module
PMT
Pulser box (UV LEDs)
Light injection manifold
Calibrates the PMT /electronics chain, but not
the scintillator/ fiber.
Linear PIN diode (stable to 0.5 over several
months. Charge injection system linearizes the
readout electronics for the PIN)
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Linearizing PMT / Electronics

• Linearizing PMT / electronics response
• Light is injected over a range of intensity. PIN
  diode monitors the light output and is used to
  convert the ADC scale to light.
• Full LI runs are taken on the order of once a
  month.

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2 Drifting in response

• CR rate at the far detector is only 500 / strip /
  month.
• LEDs are flashed at a constant height every hour.
  

From CalDet (R. Nichols)
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Minerva Calibration

• In my opinion the important first task is
  defining the calibration requirements imposed on
  us by our physics mission
• Calibrate Electronics, scintillator/fiber
  system, timing, B-field, single particle
  response.
• I am assuming we will require a test beam run in
  e/p/p/m beams from several hundred MeV to a few
  GeV.

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Minerva Calibration

• I am assuming we will require a test beam run in
  e/p/p/m beams from several hundred MeV to a few
  GeV.
• Where?
• When?
• What subsystems?

For MINOS, hadron comparisons to GHEISHA,
GFLUKA, GCALOR and SLAC-GHEISHA show large
differences
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Calibration Detector (2 GeV)
MIPs
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Calibration Detector
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Minerva Calibration

• One clear physics strength
• is particle ID.
• Requires good absolute
• calibration of the strips
• as well as good strip to
• strip calibration.
• Repeat Daves previous studies
• to determine our requirements on
• strip to strip calibration?

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Calibration Discussion

• From a quick calculation the muon rates seen by
  Minerva in the near hall are approximately
• 400k beam muons / month
• 500k stopping CR muons / month
• 6k CR hits / strip / month
• Muon rates are probably sufficient to monitor
  gain drifts.
• What will we use muons to calibrate?
• Strip positions (need to know at mm level)
• Strip-to-strip calibration
• Attenuation correction for full strip after fiber
  insertion?
• What timescale will be necessary.

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MINOS m light output
Large corrections are also related to the
attenuation in the fiber.
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Calibration in Assembly - MINOS
5mCi Cs-137 (662keV g) Determine Light
output Strip position to 1mm
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Module Mapper Results

• Tests EVERY strip
• Both ends
• 8cm steps
• Maps light output, reproducible to 1
• 40 minutes/module

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Module Uniformity
11 Variation (s) with over 90 of Production
179,000 Strip Ends Completed Only 290 show any
damage lt0.2