Beam background monitoring in the commissioning of SuperKEKB DPG - - PowerPoint PPT Presentation

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Beam background monitoring in the commissioning of SuperKEKB DPG - - PowerPoint PPT Presentation

Sep 14, 2023 160 likes •369 views

CLAWS Phase II: Beam background monitoring in the commissioning of SuperKEKB DPG conference Mnster Mar 30, 2017 Daniel Heuchel Max-Planck-Institute for Physics heucheld@mpp.mpg.de Mar 30, 2017 1 Daniel Heuchel - MPI for Physics

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SLIDE 1

Mar 30, 2017 Daniel Heuchel - MPI for Physics 1

CLAWS Phase II: Beam background monitoring in the commissioning

  • f SuperKEKB

DPG conference Münster Mar 30, 2017 Daniel Heuchel Max-Planck-Institute for Physics heucheld@mpp.mpg.de

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SLIDE 2

Outline

  • SuperKEKB and Belle II
  • CLAWS as subsystem of BEAST II
  • CLAWS Phase II: System, basics, measurements
  • Testbeam at DESY
  • Summary & Outlook

Mar 30, 2017 Daniel Heuchel - MPI for Physics 2

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SLIDE 3

SuperKEKB and Belle II II

Mar 30, 2017 Daniel Heuchel - MPI for Physics 3

  • KEKB: Asymmetric e-e+ -collider for the

investigation of CP violation:

  • High energy ring for 7 GeV e-
  • Low energy ring for 4 GeV e+
  • Currently KEKB and Belle detector undergoing

extensive commissioning campaign to SuperKEKB and Belle II:

  • Goal: Increase luminosity by factor 40 to

L = 8 x 1035cm-2s-1 for high statistics

Pixel Detector of Belle II

  • BEAST II: Commissioning detector for SuperKEKB

(Beam Exorcism for A STable Belle Experiment II)

  • Phase II (start of 2018): BEAST II instead of inner vertex

detectors of Belle II

BEAST II logo Schematic sketch of SuperKEKB

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SLIDE 4

CLAWS as subystem of f BEAST II II

Mar 30, 2017 Daniel Heuchel - MPI for Physics 4

  • CLAWS: Measurement of time evolution of

injection background and its decay constant with: → High time resolution: 0.8ns sampling rate → Continuous sampling up to the order of ms → Provide timing information for PXD gating

  • To achieve high luminosity a continuous top-off

injection at full energy is required → First rounds after injection: High background noise → Saturation of the Belle II Pixel detector (PXD) → Timed gating required → Detailed studies of the beam background time evolution inevitable!

CLAWS: Phase I measurements

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SLIDE 5

SCintillator Light And Waveform Sensors (C (CLAWS)

Mar 30, 2017 Daniel Heuchel - MPI for Physics 5

→ Plastic scintillator coupled to SiPM readout

20 mm 20 mm Unpackaged scintillator tile and a SiPM of CLAWS

Scintillator tile:

  • Design: CALICE hadron calorimeter for ILC
  • Sensitive almost entirely to charged particles
  • Packaged with self-reflecting foil to avoid photon

escape

  • Photons collected by Silicon Photo-multiplier

located in the centered dimple → Dimple preserves uniformity Silicon Photomultiplier (SiPM):

  • Mounted on PCB board
  • Hamamatsu MPPC-S13360-1325PE

CLAWS ladder with scintillators on top of SiPMs

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SLIDE 6

CLAWS - Setup

Mar 30, 2017 Daniel Heuchel - MPI for Physics 6

CLAWS Phase II ladder design

  • Two ladders with 8 channels each
  • SiPMs and amplifiers on ladder powered commonly (red)
  • High gain/low gain setting implemented (amplifier on/off)
  • Each channel read out individually with signal cable (blue)
  • Signals externally amplified and read out by 4 Picoscopes

CLAWS and other subsystems mounted on a beampipe mock up

e- e+

CLAWS ladder 2 CLAWS ladder 1

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SLIDE 7

CLAWS - Setup

Mar 30, 2017 Daniel Heuchel - MPI for Physics 6

CLAWS Phase II ladder design

  • Two ladders with 8 channels each
  • SiPMs and amplifiers on ladder powered commonly (red)
  • High gain/low gain setting implemented (amplifier on/off)
  • Each channel read out individually with signal cable (blue)
  • Signals externally amplified and read out by 4 Picoscopes

CLAWS and other subsystems mounted at a beampipe mock up

e- e+

CLAWS ladder 2 CLAWS ladder 1

20 mm

Picoscope:

  • 8 bit resolution
  • 4 channels + ext. Trigger
  • Sampling rate of 0.8 ns
  • Can store up to

400ms/channel Readout:

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SLIDE 8

CLAWS - First measurements and signals

Mar 30, 2017 Daniel Heuchel - MPI for Physics 7 Amplitude

Amplified 1pe and 2pe darkrate signal Not amplified multiple pe signal by a Sr90 source on top of one scintillator

→ Next step: Calibration and characterisation

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SLIDE 9

CLAWS - MIP IP Calibration

Mar 30, 2017 Daniel Heuchel - MPI for Physics 8

  • Calibration with minimum ionizing particles (MIPs)

→ cosmic muons

  • Sandwich structure:

→ Trigger if coincident signal on upper and lower sensor → Save and analyze the µ-signal in the middle sensor

  • Most probable value = average light yield per MIP

→ First measurements show light yield of around 30pe/MIP

µ

CLAWS: Work in progress

CLAWS calibration plot CLAWS calibration setup

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SLIDE 10

CLAWS - Darkrate characterisation

  • Darkrate of SiPMs measured with a voltage

counter

  • 4pe darkrate is low (below 1 Hz)

→ Comparison to 30pe MIP signals with GHz rate in accelerator (4ns bunch spacing) → Darkrate is negligible

  • CLAWS is noise-free

Mar 30, 2017 Daniel Heuchel - MPI for Physics 9

Darkrate over counter treshold voltage for 3 channels of a CLAWS ladder

1pe 2pe 3pe 4pe CLAWS: Work in progress

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SLIDE 11

Testbeam at DESY

Mar 30, 2017 Daniel Heuchel - MPI for Physics 10

  • Testbeam with e- at DESY in Hamburg
  • Two CLAWS ladders installed
  • e- beam perpendicular to CLAWS ladders
  • Operation with and without 1.5 T magnetic field

The two CLAWS ladders mounted on the testbeam mock up with other subsystems

e-

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SLIDE 12

Testbeam at DESY

Mar 30, 2017 Daniel Heuchel - MPI for Physics 11

CLAWS DAQ for Phase II during data taking of single MIP signals with an external trigger (blue): Simultaneous e- signals in two channels of the bottom ladder

  • Measurements with different dynamic ranges and settings
  • Measurements of single MIPs
  • Constant recording over 20 ms with more than 50 MIPs in one waveform
  • Successfully operated in High gain and Low gain mode during data taking

→ Analysis ongoing 4 channels of top ladder External trigger 3 channels of bottom ladder e- signals

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SLIDE 13

Summary ry & Outlook

  • Injection background in the SuperKEKB accelerator, appearing the first rounds after a

top-off injection, has to be investigated in detail → Avoid saturation of the Belle II PXD by timed gating

  • Therefore, CLAWS in Phase II, as part of BEAST, will replace a future Belle II vertex

detector and measure timing properties and particle rates of the injection background

  • CLAWS: Plastic Scintillator with a SiPM readout for fast timing
  • Phase II design: Two CLAWS ladders with 8 channels each
  • Characterisation and Calibration measurements on going
  • Three successfull testbeam weeks at DESY showing that the CLAWS Phase II design

works and the CLAWS system is on track for Phase II → Analysis of the measurements on going Mar 30, 2017 Daniel Heuchel - MPI for Physics 12

  • Hardware installation November 2017 and Phase II data taking early 2018
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SLIDE 14

Mar 30, 2017 Daniel Heuchel - MPI for Physics 13

Thank you very much for your attention!

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SLIDE 15

Mar 30, 2017 Daniel Heuchel - MPI for Physics

BACKUP

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SLIDE 16

BEAST II II - Commissioning Schedule

After the major upgrade of the KEKB accelerator Phase I (Feb 2016 – June 2016):

  • No Belle II detector
  • No beam focusing optics
  • Injection in HER or LER

Phase II (autumn 2017 – spring 2018):

  • Belle II (without VXD)
  • Optics for nano-beam scheme

Phase II (starting mid 2018):

  • Full Belle II detector
  • Real physics collisions

Mar 30, 2017 Daniel Heuchel - MPI for Physics

BEAM EXORCISM FOR ASTABLE BELLE EXPERIMENT II

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SLIDE 17

Theory ry

Mar 30, 2017 Daniel Heuchel - MPI for Physics

  • CME of 10.58 GeV -> Resonance Y(4s) -> Decays mostly into bb -> b-factory
  • Investigation of CP violating b decays, bb mixing!
  • Different decay times, positions? Vertex and Pixel detectors with high spatial

resolution for investigation Belle II

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SLIDE 18

CLAWS – Phase I I timing measurements

Mar 30, 2017 Daniel Heuchel - MPI for Physics CLAWS Phase I data

  • Compare

measurements with design properties: → Bunch timing in double bunch injection: 96.285ns → Revolution time: 10.061 ns

  • Measure decay time
  • f noise coming from

injected bunches

  • Measure particle

rates of noise

10.06µs

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SLIDE 19

CLAWS - Measurements

What does CLAWS measure in detail?

  • Time evolution of the beam background

→ Sensitive to charged particles → High time resolution: 0.8ns sampling rate → Continuous sampling up to the order of ms

  • Intra-bunch interactions create different types
  • f background at the interaction point:

→ Regular signals from circulating bunches with small amplitude → Signals of top-off injected daughter bunches with high amplitude (Signals decrease turn by turn) Mar 30, 2017 Daniel Heuchel - MPI for Physics CLAWS Phase I data

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SLIDE 20

CLAWS - System and Basics

Mar 30, 2017 Daniel Heuchel - MPI for Physics SCintillator Light And Waveform Sensors → Plastic scintillator coupled to SiPM readout

20 mm 20 mm

Unpackaged scintillator tile and SiPM of CLAWS Scintillator tile:

  • Design taken from CALICE hadron calorimeter for

ILC

  • Sensitive almost entirely to charged particles
  • Tiles are packaged with self-reflecting foil to avoid

photon escape

  • Photons are collected by the Silicon Photo-

multiplier located in the centered dimple → Dimple preserves uniformity Silicon Photomultiplier (SiPM):

  • Mounted on PCB board within the centered

dimple of the scintillator tile

  • SiPM is an array of avalanche photodiodes in

limited Geiger mode

  • Hamamatsu MPPC-S13360-1325PE:

→ 2668 pixels → Typical operation voltage 55-60 V Picoscope 6404D:

  • 8 bit resolution
  • 4 channels + ext. Trigger
  • Sampling rate of 0.8 ns
  • Can store up to 400ms/channel

Readout: