Optical Transition Radiation Monitor for the T2K experiment - - PowerPoint PPT Presentation

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Optical Transition Radiation Monitor for the T2K experiment - - PowerPoint PPT Presentation

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Optical Transition Radiation Monitor for the T2K experiment Mitchell Yu York University 2017/09/18 Overview The T2K experiment The Optical Transition Radiation (OTR) monitor OTR monitor operation history OTR monitor operation

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SLIDE 1

Optical Transition Radiation Monitor for the T2K experiment

Mitchell Yu York University 2017/09/18

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SLIDE 2

Overview

17-09-18 NBI2017 - Mitchell Yu - York University 2

  • The T2K experiment
  • The Optical Transition Radiation (OTR)

monitor

  • OTR monitor operation history
  • OTR monitor operation status
  • Future OTR monitor upgrade plans
  • OTR foil radiation damage study
  • Summary
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SLIDE 3

NBI2017 - Mitchell Yu - York University 17-09-18 3

The T2K experiment

  • The Tokai-to-Kamioka

long baseline neutrino

  • scillation experiment

(T2K) uses an intense neutrino (antineutrino) beam produced by the collision between J- PARC’s 30GeV proton beam and a graphite target

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SLIDE 4

Optical Transition Radiation (OTR) Monitor

  • T2K neutrino beam position is reconstructed by

using measurements from the ESMs, the SSEMs, and the OTR

  • The Optical Transition Radiation (OTR) Monitor is

the most downstream proton beam monitor located 30cm upstream of the T2K target

  • The beam profile parameters measured by the OTR

are used both for the beam commissioning and for the neutrino flux prediction

  • 2D beam profile is also reconstructed for the OTR

live online monitor (continuous beam position and profile monitoring during physics run)

17-09-18 NBI2017 - Mitchell Yu - York University 4

proton beam direction

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SLIDE 5

NBI2017 - Mitchell Yu - York University 17-09-18 5

Optical Transition Radiation (OTR) Monitor

  • A 50 µm-thick Ti foil is

placed between the proton beam target and the collimator

  • The foil (45o w.r.t. beam)

produces backward optical transition radiation (light produced when charged beam pass through the foil) perpendicular to the beam

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SLIDE 6

Optical Transition Radiation (OTR) Monitor

  • The OTR optical system

consists 4 parabolic mirrors

  • Transports the light

(optical transition radiation)

  • Harsh environment (5e8

Sv/h) near the target

  • Camera (radiation hard

CID camera) placed at a lower radiation area to capture the light

17-09-18 NBI2017 - Mitchell Yu - York University 6

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SLIDE 7
  • No target - no OTR measurement
  • Ceramic foil – produces fluorescent

light with low intensity beam (up to 40kW), used during beam commissioning

  • Calibration foil – with holes in a

grid, used for calibration with external light sources

  • Titanium foils – Ti1 used during

beam operation, Ti2-4 are spares

  • Cross foil – titanium foil with a

cross pattern, used for in beam calibrations

  • Currently used in beam

17-09-18 NBI2017 - Mitchell Yu - York University 7

— The remotely rotatable OTR disk has 8 different foils which

serve various purposes

“Cross foil”

Optical Transition Radiation (OTR) Monitor

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SLIDE 8

Calibration foil image in OTR camera

  • Hole position on the calibration foil

surveyed relative to horn axis during installation

  • Filament or laser light backlights the

calibration foil and the images are saved periodically

  • Hole positions in the calibration foil

image and survey results are used for image correction

  • Absolute position
  • Distortion correction

NBI2017 - Mitchell Yu - York University 17-09-18 8

Optical Transition Radiation (OTR) Monitor

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SLIDE 9

NBI2017 - Mitchell Yu - York University

  • Proton beam monitors measurements

are extrapolated to calculate the proton beam position and angle at the target

  • The OTR measurement reduces

uncertainties of extrapolation

  • When OTR data is included:
  • σx 0.5 à 0.5 mm
  • σy 2.3 à 0.5 mm
  • σθx 0.08 à 0.08 mrad
  • σθy 0.5 à 0.3 mrad
  • Bigger improvements on Y (off-axis

angle)

  • Vertical (y) bending magnet after

SSEM17

  • Can only use SSEM18 and SSEM19

(very close together) for extrapolation

  • OTR measurement provides the 3rd

point for the fit

17-09-18 9

Impact of the OTR monitor measurement

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SLIDE 10
  • OTR1 (slide 11)
  • Stable operation between 2009 – 2013
  • OTR2 (slide 12 – 13)
  • Assembled, calibrated and tested in 2011
  • Operation between 2013 – present
  • Minor problems appeared from Mar. 2015
  • Motor disconnected, OTR disk fixed at cross foil position since Jan. 2016
  • OTR3 (slide 14)
  • Arm, disk, mirror 1-2 tube, mirror 3 tube
  • Assembled, calibrated and tested in 2014
  • Spare system
  • Exchange rehearsal using the manipulator arm system in the remote maintenance area

(RMA) performed in Dec. 2015

  • Disk flange replaced
  • Ti foil modification
  • OTR4
  • Currently being built

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OTR monitor operation history

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SLIDE 11
  • OTR1 operated

stably for 6.6e20 protons on target

NBI2017 - Mitchell Yu - York University

OTR light linearity with beam intensity Consistent with beam line SSEM monitors OTR profile on Ti foil 9e13 protons

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OTR1 Operation Status

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SLIDE 12

NBI2017 - Mitchell Yu - York University 17-09-18 12

OTR2 Operation Status

  • Problem with the OTR disk rotation mechanism noticed on Aug. 2015
  • Possible disk flange and plunger damage might be the reason
  • Independent test of the commercial plungers indicate spring failure after large number of compressions
  • Decided to put the cross foil in beam position and not to rotate the disk to prevent further damage
  • The OTR monitor has been operating stably with the cross foil since Feb. 2016
  • Light yield decreases as exposure increases
  • Need to change foil before the light yield becomes too low for the analysis
  • OTR1 Ti2 foil survived 5.0e20 POT
  • OTR2 Ti1 foil has been exposed to 5.0e20 POT
  • OTR2 Cross foil has been exposed to 1.1e21 POT
  • OTR2 still has 3 spare Ti foils to use if needed
  • No problem for the proposed additional 0.8e21 POT until 2018

Stainless steel plunger Ti disk flange

May 2014 OTR2 installed

  • Feb. 2016

Switch to Cross foil

  • April. 2017
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SLIDE 13

9 August 2017 13

July 2017 inspection Ti1 foil: ~5x1020 POT Cross foil: ~11x1020 POT Cross foil Ti1 foil August 2015 inspection Ti1 foil: ~5x1020 POT Cross foil: ~0x1020 POT

Future foil radiation damage studies OTR2 Foil Status

Cross foil Ti1 foil

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SLIDE 14

NBI2017 - Mitchell Yu - York University 17-09-18 14

OTR3 Upgrade Status

  • Ti disk flange à stainless steel disk flange
  • Harder surface to prevent damage during disk rotation
  • Commercial plunger à customized plunger
  • Customized spring for more robust performance
  • Machine 4 holes on each Ti foil
  • For calibration usage
  • Plan to use Ti-6A-4V (grade 5)

foils instead of current Ti-15V-3Cr-3Sn-3Al

  • Same as in He vessel beam

window

  • Important Ti alloy for post-

irradiation studies

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SLIDE 15
  • OTR1 foils

(Ti-15V-3Cr-3Sn-3Al) are world’s most irradiated Ti specimens

  • Ti1: 1.6e20 POT
  • Ti2: 5.0e20 POT
  • Ti1 foil was transported to

PNNL on Jan. 2016 for post- irradiation examination

  • Different grain structure at

surface where discoloration is visible

  • Discolored region at surface

made of Si-0/Ti-C layers

  • Si may come from vessel-

evacuating booster-pump oil

  • Andy Cassela’s talk: PNNL

(Graphite/ Ti) in the RaDIATE session

NSERC 2016 Review

Elemental mapping TEM image Ti1 foil

Dec 12, 2016 15

OTR1 foil radiation damage studies

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SLIDE 16

NBI2017 - Mitchell Yu - York University 17-09-18 16

Future foil radiation damage studies

  • OTR1 foils (Ti-15V-3Cr-3Sn-3Al) are world’s most

irradiated Ti specimens

  • OTR2 foils (Ti-15V-3Cr-3Sn-3Al) will also be used for

future radiation damage studies

  • Ti1: 5.0e20POT
  • Cross foil: 1.1e21POT (will be increased)
  • Potentially 1.9e21POT if OTR operates with the cross

foil alone until 2018

  • OTR3 will have Ti-6A-4V (grade 5) foils installed
  • Possible switch to OTR3 in summer 2018
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SLIDE 17

Summary

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  • The Optical Transition Radiation (OTR) monitor

measure proton beam profile with Ti foil in the beam using optical transition radiation light

  • OTR1 operated stably between 2009 - 2013
  • OTR2 is current used, it has minor problems but

is operating stably

  • Upgrades are being made on the spare systems

OTR3 and OTR4

  • OTR1 foils were the world’s most irradiated Ti

specimens (5e20 POT)

  • OTR2 foils will become the world’s most

irradiated Ti specimens (1.9e21 POT)

  • Future OTR will use Ti-6A-4V foils
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SLIDE 18

OTR group

  • The OTR group built and installed the OTR monitor
  • Entirely a Canadian responsibility
  • Led by S. Bhadra (York U.), A. Konaka (TRIUMF) and
  • J. Martin (U. Toronto )
  • Current and former members:

NSERC 2016 Review

  • Postdocs

– Alysia Marino U. Toronto (06-09) è faculty U. Colorado – Mark Hartz U. Toronto /York U.(09-13) è faculty TRIUMF/IPMU – Arturo Fiorentini York U. (13- )

  • Undergrad students (07-13)

– Patrick de Perio U. Toronto – Slavic Galymov York U. – Don Teo York U. and U. Toronto – Eoin O’Dwyer TRIUMF – Jordan Myslik U. Toronto – Stephen Ro U. Toronto – Shu Wang York U. All now grad students or have PhD

  • Grad students

– Brian Kirby MSc York U. 07 è UBC PhD èpostdoc U. Hawaiiè BNL – Leif Stawnyczy MSc York U. 09 – Slavic Galymov PhD York U. 11 è faculty IPNL Leon – Patrick de Perio PhD U. Toronto 14 è postdoc Columbia U. – Elder Pinzon PhD York U. – Mitchell Yu PhD York U. – Mark McCarthy PhD York U.

  • Technical

– Dave Morris TRIUMF

  • Designer - DAQ, electronics

– Mircea Cadabeschi U. Toronto

  • Mechanical engineer
  • Retired but still working for us on contract

Dec 12, 2016 18