NuMI Hadron and Muon Monitoring Fermilab UWisconsin UTexas -- - - PowerPoint PPT Presentation

▶
numi hadron and muon monitoring
SMART_READER_LITE
LIVE PREVIEW

NuMI Hadron and Muon Monitoring Fermilab UWisconsin UTexas -- - - PowerPoint PPT Presentation

Nov 10, 2022 416 likes •669 views

NuMI Hadron and Muon Monitoring Fermilab UWisconsin UTexas -- Austin Robert Zwaska University of Texas at Austin NBI 2003 November 10, 2003 System Geography + Alcove 1 Alcove 2 Alcove 3 + Hadron Monitor Muon Monitors Max

slide-1
SLIDE 1

NuMI Hadron and Muon Monitoring

Fermilab UWisconsin UTexas -- Austin

Robert Zwaska University of Texas at Austin NBI 2003 November 10, 2003

slide-2
SLIDE 2

System Geography

π+ µ+ υµ

Hadron Monitor

  • Max fluxes 109/cm2/spill
  • Rad levels ~2 × 109 Rad/yr.

Muon Monitors

  • Max fluxes 4 107/cm2/spill
  • Rad levels ~ 107 Rad/yr.

Alcove 1 Alcove 3 Alcove 2 November 10, 2003 Robert Zwaska NBI 2003 2

slide-3
SLIDE 3

109 Particles / cm2 / spill 3.0 2.5 2.0 1.5 1.0 0.5 0.0

Alcove 1 Alcove 2 Alcove 3

107 106 Muons / cm2 / spill

Radius (cm)

Particle Fluences

  • Neutron fluences are ~ 10× that of charged particles at

Hadron Monitor & Alcove 1 locations

  • Hadron Monitor insensitive to horn focusing
  • Muon Monitor distributions flat

November 10, 2003 Robert Zwaska NBI 2003 3

slide-4
SLIDE 4

Role of Monitors

  • Commissioning the beam – check of alignment

Proton beam – Hadron Monitor Neutrino beam – Muon Monitor

  • Normal beam operations – ensure optimal beam

Proton beam angle – Hadron Monitor Target integrity – Hadron Monitor Horn integrity, position – muon monitor

  • Re-commissioning the beam if optics moved

November 10, 2003 Robert Zwaska NBI 2003 4

slide-5
SLIDE 5

Information in Alcoves

  • Hadron Monitor swamped by π’s, protons, e+e−
  • Alcoves have sharp cutoff energies
  • Even Alcove 1 doesn’t see softest parents

1 2

November 10, 2003 Robert Zwaska NBI 2003 5

slide-6
SLIDE 6

Flexible Energy Beam

November 10, 2003 Robert Zwaska NBI 2003 6 Target 10 m 0.35 – 3.96 m

  • Low Eν beam flat, hard to monitor

relevant parent particles.

  • Best way to focus higher energy

pions: focus smaller angles.

  • Place target on rail system

for remote motion capability.

  • M. Kostin, S. Kopp, M. Messier,
  • D. Harris, J. Hylen, A. Para
slide-7
SLIDE 7

Variable Beam as Monitoring Tool

  • Muon alcoves have narrow acceptance (long decay

tube!)

  • As Eν increased, decay products boosted forward
  • See peak in particle fluxes as energy increases
  • Use variable

beam as periodic monitoring diagnostic

  • D. Harris

1 2 3

November 10, 2003 Robert Zwaska NBI 2003 7

slide-8
SLIDE 8

Muon Monitors

2 1

  • Alignment of ν beam

Beam center to ~ few cm Lever arm is 740, 750, 770 m ν beam direction to ~ 100 µrad Can measure in 1 beam spill Requires special ME/HE running

  • As beam monitor

Rates sensitive to targeting Centroid sensitive to horn focusing Centroid requires ME/HE run (1 spill)

November 10, 2003 Robert Zwaska NBI 2003 8

slide-9
SLIDE 9

Parallel Plate Ion Chambers

  • 11.4 × 11.4 cm2 Al2O3 ceramic wafers
  • Ag-plated Pt electrodes
  • Similar HV ceramic wafer
  • Holes in corners for mounting
  • Vias to solder pads on reverse side.
  • Separate mechanical support and

electrical contacts

  • Adopt design with electrical &

mechanical contacts in corner holes Chamber gap depends on station

  • Ionization medium: Helium gas at

atmospheric pressure

Sense wafer, chamber side

November 10, 2003 Robert Zwaska NBI 2003 9

slide-10
SLIDE 10

Booster Beam Test

Fermilab Booster Accelerator

8 GeV proton beam 5×109 - 5×1012 protons/spill 5 cm2 beam spot size

  • Two chambers tested (1mm

& 2mm gas gap)

  • 2 PCB segmented ion

chambers for beam profile.

  • Toroid for beam intensity

10 November 2001

slide-11
SLIDE 11

High-Intensity Beam Test

  • R. Zwaska et al., IEEE Trans.
  • Nucl. Sci. 50, 1129 (2003)

Fermilab Booster

8 GeV proton beam 5×109 - 5×1012 protons/spill 5 cm2 beam spot size 1mm and 2mm chamber gaps tested

  • See onset of charge loss at

4×1010 protons/cm2/spill.

  • Effect of recombination as chamber

field is screened by ionization.

slide-12
SLIDE 12

Simulating a Chamber

Predict Behavior seen in beam test 1 Dim. finite element model incorporating: Charge Transport Space Charge Build-Up & Dead Zone Gas Amplification Recombination

Dead Zone 3x Applied Field!

1 mm separation 200 V applied 1.56 µs spill

1E10 1E11

slide-13
SLIDE 13

Simulate Multiplication and Recombination

Use the same volume recombination: Include gas multiplication: Space Charge creates an electric field larger than the applied field Upturn

− +

− = n kn dt dn

α N dx dN =

α P = Aexp − B (E / P) ⎡ ⎣ ⎢ ⎤ ⎦ ⎥

Data ⇔ Simulation

slide-14
SLIDE 14

Plateau Curves

Curves converge in a region of voltage near a gain of 1

Data suggests 15-20 electron-ion pairs / cm

Data ⇔ Simulation

Crossing point moves with multiplication More Mult. ← ← → → Less Mult.

slide-15
SLIDE 15

Neutron Backgrounds

  • Neutron Fluxes are comparable

to charged particle fluxes

10x in Hadron Monitor 10x in Muon Monitor 1

  • From Beam Dump

Smaller in other locations

  • Neutrons create ionization by

nuclear recoils

  • Measured ionization from

PuBe neutron sources

1-10 MeV 55 Ci

November 10, 2003 Robert Zwaska NBI 2003 15

slide-16
SLIDE 16

Neutron Signals

  • D. Indurthy et al, submitted to Nucl. Instr. Meth.

He Gas He Gas Ar Gas Ar Gas

Ion Pairs / cm He Gas Ar Gas Neutrons 1.1 ± 0.2 9.6 ± 2.6

Charged Particles

16 120

Results ⇒ signal:noise is 1:1 in monitors?

  • preliminary-

November 10, 2003 Robert Zwaska NBI 2003 16

slide-17
SLIDE 17

System Design

  • Hadron Monitor

7x7 grid → 1x1 m2

  • 1 mm gap chambers

Radiation Hard design Mass minimized for residual activation

  • 57 Rem/hr
  • Muon Monitors

9 tubes of 9 chambers each → 2.2x2.2 m2

  • 3 mm gap chambers

Tube design allows repair

  • High Voltage (100-500 V) applied over He gas

Signal acquired with charge-integrating amplifiers

slide-18
SLIDE 18

November 10, 2003 Robert Zwaska NBI 2003 18

Radiation Damage Tests

  • Delivered 12GRad ≈ 9NuMIyrs

PEEK Al2O3 ceramic Ceramic putty Kapton cable Swagelok Ceramic circuit board

@ UT Nuclear Engineering Teaching Lab Reactor

slide-19
SLIDE 19

Hadron Monitor Construction

rear feedthrough base front window

November 10, 2003 Robert Zwaska NBI 2003 19

slide-20
SLIDE 20

Muon Monitor Construction

November 10, 2003 Robert Zwaska NBI 2003 20

  • All detectors

complete

  • D. Indurthy, M. Lang,
  • S. Mendoza, L. Phelps, M. Proga,
  • N. Rao, R. Zwaska
slide-21
SLIDE 21

Assembly

November 10, 2003 Robert Zwaska NBI 2003 21

1 µCi 241Am α Calibration Source Signal Cables Tray HV cables

slide-22
SLIDE 22

Muon Monitor Calibration

  • Establish relative calibration of all 270

chambers to <1%.

  • Irradiate every chamber with 1Ci

Am241 source (30-60 keV γ’s)

26 / (27+5) Tubes 26 / (27+5) Tubes Calibrated Calibrated

  • S. Mendoza, D. Indurthy, Z. Pavlovich
  • Precision of ion current ~0.1pA
  • Results show ~10% variations

due to construction variations

November 10, 2003 Robert Zwaska NBI 2003 22

slide-23
SLIDE 23

Summary

  • Hadron & Muon Monitors provide information on:

Beam alignment (proton & secondary) Target Integrity Optics Quality

  • Signals come from hadrons, muons, and neutrons
  • Variable energy beam allows more information to be collected
  • Detector hardware tested at high intensity

Linearity is adequate Behavior is understood through simulation

  • Neutron backgrounds estimated & characterized

Neutron signal might be comparable to (other) hadron signal

  • Systems designed, built, & calibrated

Components tested for radiation damage

November 10, 2003 Robert Zwaska NBI 2003 23