COMPASS++/AMBER Proton-Charge Radius Measurement Pilot Run 2021 - CERN Indico

COMPASS++/AMBER Proton-Charge Radius Measurement

 Pilot Run 2021
Jan Friedrich
Technical University of Munich
Physics Department

EHN2 Working Group Meeting

September 29th 2020
CERN / Vidyo

On behalf of the Proton Charge-Radius Working Group
COMPASS++/AMBER Proto-Collaboration

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Schedule for Proton-Charge Radius Measurement
 Preliminary feedback SPSC April meeting:
Planning for the upcoming three years “The AMBER proton radius experiment (core program) will
 likely run in 2022, keeping again in mind that at this point
Schedule for the setup, preparation and pilot run with the it is not at all clear how much NA operations will be delayed.”
following main data taking and concluding systematic
studies. SPSC Minutes April Meeting (CERN-SPSC-2020-013):
 “The SPSC recommended a pilot run for Amber
 (SPSC-P-360) on M2 in 2021.”

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 2

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Simulation of the New Setup
New implementation of adapted setup

Different geometry of COMPASS spectrometer and tracking combined
with new detector components.
• Setup geometry implemented in TGEANT
• Only SM2 magnet:
 → Bridging, momentum reconstruction and vertexing e-
 p
 → Adaption of detector planes ongoing

 Ionisation position y (mm)
• TPC implementation:
 → Energy-loss + propagation (GARFIELD++/ANSYS)
 → Simple track reconstruction
 → Detailed studies on beam-noise / background ongoing
• Silicon detectors: Ionisation position x (mm)

 → Modular pixelized silicon detectors implemented
• Fiber detectors:
 → Fiber-tracker with individual fibers implemented
• Event Generator:

 Amplitude (a.u.)
 → Elastic kinematics with unscattered background tracks
 → Support for general ROOT event files (ext.: i.e. rad. gen. (ESEPP))
• New “event” definition due to tigger-less DAQ:
 → Updates in analysis chain (HLT Frame Work) Signal time (us)

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 3

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Simulation of the New Setup
New implementation of adapted setup

Different geometry of COMPASS spectrometer and tracking combined
with new detector components.

 modular pixel-silicon plane
• Setup geometry implemented in TGEANT
• Only SM2 magnet:
 → Bridging, momentum reconstruction and vertexing
 → Adaption of detector planes ongoing
• TPC implementation:
 → Energy-loss + propagation (GARFIELD++/ANSYS)
 → Simple track reconstruction
 → Detailed studies on beam-noise / background ongoing
• Silicon detectors:
 → Modular pixelized silicon detectors implemented
• Fiber detectors:

 Single-fiber tracker
 → Fiber-tracker with individual fibers implemented
• Event Generator:
 → Elastic kinematics with unscattered background tracks
 → Support for general ROOT event files (ext.: i.e. rad. gen. (ESEPP))
• New “event” definition due to tigger-less DAQ:
 → Updates in analysis chain (HLT Frame Work)

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 4

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Studies on Material Budget and Q2-Resolution
 Influence of multiple scattering on Q2-resolution

 Minimise material budget to lower the effect of multiple
 scattering allows redundant measurement.

 Q2 (GeV2/c2)
 • Direct Measurement of Q2 via TPC:
 ΔQ2/Q2min < 0.06 (Q2min = 10-3 GeV2/c2)
 • Muon scattering:
 ΔQ2/Q2min < 0.13 (Q2min = 10-3 GeV2/c2)
 • Example: increase fiber thickness 0.2 mm to 1.0 mm
 Q2MC (GeV2/c2)
 → 0.2 % X/X0 to 1% X/X0 (+25% total)
 K. Eichhorn (TUM)
 → Effect of 1.6 % on reconstructed Q2 (+11 % total)

 • Smearing of Q2-spectrum due to multiple scattering
 → Minimise material budget for better comparison
 → Correct for effect of multiple scattering required

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 5

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Detector Status - Silicon Pixel Detector
 Maxim Alekseev, Stefania Beole (Torino)
Design and development of new silicon pixel-detector stations

Modular silicon pixel detector for precise tracking with low material-
budget required.
• Two types under investigation: ALPIDE, MuPix
• ALPIDE:
 → Working modules available
 → 28 μm pixel size
 → Low material-budget (X/X0 about 0.3 - 0.4 %)
 → 5 μs time resolution - requires external precision timing
 → Currently: design studies (material budget and cooling)

• MuPix: →
 Still under development (used in Mu3e at PSI)
 → 80 μm pixel size
 → ~ 10 ns time resolution
 → Currently: test setup at TUM
 55
 Fe-source

• First estimate for construction of four stations:
 → 3-5 month for construction
 → Testing required at each constriction step
COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 6

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Detector Status - Time Projection Chamber
Construction of a new TPC

New TPC vessel and readout parts required.
• New TPC construction:
 → 4x drift cells with 400 mm length
 → Maximal operation pressure: 20 bar
 → Segmented anode plane: 600 mm diameter
• Construction of TPC about 1.5 years in total
 → Split work and construction to be on time
 d = 300 mm

 10 MeV 20 MeV

 Optimisation of geometry ongoing:
 • Material budget, beam noise and proton ranges
 → optimal pressure settings for Q2-range
 1 MeV 5 MeV → optimal internal geometry
 → optimal read-out plane segmentation
 → optimal beam-window size

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 7

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Time Projection Chamber - Pad Plane
Segmented readout pad-plane for reconstruction

Proton track reconstruction based on radial segmented anode plane
provides position, angle and energy measurement.

 M. Hoffmann, F. Metzger, (U Bonn) A. Dzyuba, E. Maev, A. Ignlessi (PNPI)
• Various radial designs were under studied with different types of
 segmentation:
 → Influence on φ-, x/y-, energy resolution
 → Crucial: Pad size affects deposit charge

• Realistic beam and electronic noise simulated over drift time
• Event reconstruction based on signal extraction

• Decision for pilot run 2021: Hybrid solution
• Beam ionisation distributed among central pads (5 mm + 45 mm)
 → φ-resolution better than 20°
 → Pad sizes optimised for beam ionisation and deposit charge
 → E-resolution better than 100 keV + 20 keV with σbeam + σelec

• Resolutions sufficient for reliable matching (< 0.35 % misidentification)

 8

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Detector Status - Fiber Tracker
Development of novel 200-μm fiber trackers
Novel fiber tracker detector with single 200-μm fiber read-out. Precise
tracking, triggering and timing.

• Stage 1: Test setup and feasibility test (2020) (ongoing)
 → Readout of single 200-μm fibers with two SiPMs.
 → Trigger on coincidence signals in each fiber - noise reduction

• Stage 2: 400-channel prototypes (until summer 2021) (in preparation)
 → Develop front-end and data-fusion electronics
 → Identical mechanics, populate only inner fibers of each layer.
 → Evaluation of performance before and during pilot run

• Stage 3: Tracking / Timing / Trigger test (optional, until winter 2021)
 → Test of detector purpose: timing / trigger (3x stations)

• Stage 4: Full PRM Setup (until begin of 2022)
 → Construction and tests of final fiber tracking stations

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 9

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

DAQ Status - Continuously Running
New DAQ development

A concept applying continuous DAQ based on the
following principals:

• Ongoing new DAQ development with data-rate capability 2·106 Hz
 from 5 - 40 GB/s starting from 2021.
 → PCRM: about 3 GB/s expected in 2021/2022

• About 15 GB/spill (4.8 s) - 7 PB (year’s total):
 → 4x more data compared to COMPASS (2018)

• Increase in data rate requires a reduction of recorded
 events:
 → High-level or hardware trigger (Kink trigger)

• Beam rate limitations:
 → Bottleneck: active-target TPC (beam noise)
 → Tracking detectors more than 4·107 Hz

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 10

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Pilot Run 2021 - Part Ia: Downstream Location
Part I: Parasitic tests at downstream location

Many general beam / equipment tests can be performed
in parasitically to COMPASS run at the test location and
the laboratory.

• From beam test in 2018:
 → broad muon beam (position and momentum)

• General test of basic beam related features
 → background / noise / tracking / alignment

• DAQ, infrastructure and quality assurance tests

• Limited space (other tests and HI05) and access~ 8 metres (2018)
 → only simple “flying” tests of components
 ~ 4 metres (2021)

 Beam

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 11

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Pilot Run 2021 - Part Ib: CEDAR Location
Part II: Tests at CEDAR location

Precise beam / measurement tests can be performed close to
final measurement conditions.

• From simulations:

 Provided by D. Banerjee and J. Bernhard
 → Well-focused beam - similar to final target position in 2022

• Allows beam-profile related tests:
 → Beam-rate studies

• Pilot run with similar conditions to 2022/2023

• 20 days dedicated run

 ~13 metres

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 12

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Detector Status - TPC for Pilot Run 2021
Adaption of existing and construction of a new TPC

IKAR TPC can be adapted to be comparable with new
development. In parallel: new TPC can be built.
• IKAR TPC at GSI:
 → Conversion: 6x drift cells (100 mm) into 2x drift cells (400 mm)
 → New signal outputs: 16x one-channel into 4x 16-channels.
 → High-voltage: 2x 20 kV connectors by new 10 / 50 kV
 → New field-shaping rings (20x)
 → Anode structure: 32 ring/sector structure
 → Two different layouts can be tested
 → Next steps: transport to CERN in October and apply changes
• Properties:
 → Diameter 740 mm and length: 1600 mm
 → Gas volume: 0.55 m3 with operation pressure of 10 bar (max)
 → Windows: Be 70 mm with 0.5 mm thickness
 → Anode: outer diameter 490 mm
• New equipment required/available*:
 → Electronics*, HV-supplies*, vacuum*, safety and gas system Production of items / delivery ongoing.
 → Advantage: can be request for main TPC Refurbishment start foreseen for
 October at CERN.

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 13

Institute for Hadronic Structure and Fundamental Symmetries
 Physics Department
 Technical University of Munich

 Timeline for Proton-Charge Radius Measurement
 Full down-scaled setup tested at the end of 2021 - preparation for data taking in 2022

 Developments constantly on-going. Single parts need to be tested under final conditions with
 the goal of ready complete setup for beginning of 2022.
 • Phase 0 - 2020: →
 Detailed studies of the measurement (background/noise/systematics)
 → Development of detectors/prototypes (silicon/fiber/TPC) and DAQ
 → Preparation of prototypes for 2021 and final detectors for 2022
 • Phase I - 2021:
 → Part a: parasitic beam tests downstream of COMPASS
 → Part b: dedicated 20-day pilot run at CEDAR location (realistic layout/beam conditions)
 • Phase II - 2022:
 → Data taking with full setup SPSC Silicon/Fiber Pilot Run ready
PRMT (recom. Pilot Run) Beam Test Ready
 SPSC
2019 2020 (prel. feedback) IKAR 2021 2022
 Upgrade
 June December January May April October November April
 PRM PR I PRM PR II
 Proposal Q&A COMPASS run

 R&D for PRM
 Prototype development Prototype / Detector
 and testing construction
 COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 14

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Time Slots for the PCRM Pilot Run

 Given that presumably not all components for the PCRM pilot measurements will be available for
 the planned start on July 12th, we request the following time slots with beam:
 • During the whole beam time in 2021, we install a test stand downstream COMPASS
 → for testing tracking detector components, 3-4 meters
 → for testing the new readout / DAQ system
 • In the beginning ~ 5 days with 1 − 2 % 10' muons/sec for the initial testing of the TPC
 • During the beam time ~ 15 days, interleaved and in close coordination with the COMPASS data taking
 → along e.g. with AWAKE data taking, and/or in weeks 37/38 along with HiRadMat tests
 → completion of the setup in the CEDAR position

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 15

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Resources for the PCRM Pilot Run

 Investments had to be started, in order to realize the needed developments as the
 remaining time allows, despite no funding could be raised yet (since the approval in
 the last SPSC)

 A cost breakup for the pilot run has been drafted (continuously updated), indicating needed
 resources of ~ 50 kCHF.
 • within the proto-CB of COMPASS++/AMBER, the installation of a preliminary common fund
 for the pilot run has been negotiated, and several institutes agreed to contribute an amount
 ≥ 1800CHF
 • Formal agreement with the CERN Financial Department on opening a respective account
 ongoing

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 16

Institute for Hadronic Structure and Fundamental Symmetries
Physics Department
Technical University of Munich

Summary
 • The preparation for the COMPASS++/AMBER Proton Charge Radius Measurement
 Pilot Run is ongoing and progressing
 → Many new developments: trigger-less DAQ / TPC / pixel silicon / fiber tracker
 → Very tight time scales

 • Start of the new Collaboration, preliminary cost plan and sharing in construction
 → Slow approval process serious problem for fund raising

 • Test of the detector components in the coming Pilot Run
 → in close coordination with the COMPASS Collaboration
 → not all components will be available in the beginning of the beam time
 → plan to interleave with the available slots of the overall beam schedule

 Thank you for your attention

 backup material follows

 17

Principle of the Measurement

 Pacetti, Tomasi-Gustafsson EPJA (2020) 56:74
 • Electric form-factor defines the proton charge-radius at
 momentum transfer Q2 = 0:

 9. = −6ℏ. ⋅ - . ⁄ . |AB →C

 • Access to form factors -. and /
 .
 in Rosenbluth separation of the
 cross section for elastic → :

 d 59→59 4 . . . .
 = - + / =
 d . I 4 9.

 = 5. − − 5. O ⃗5N.
 .
 • Influence of the magnetic form factor / suppressed at small .

 • Measurement at high-energy 5 ~ 10 - 100 GeV = ⃗5N. O ⃗5. 1 + 
 → ≃1
 ⃗5N. = ⃗5. − − 2 9. 1 + 
 • Cross-section approximately proportional to -.

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 18

Measurement Proposal at CERN
High-energy elastic muon-proton scattering
Measurement at the CERN M2 beamline, site of the current
COMPASS experiment.
• Measure as close as possible to Q2 = 0 • Discrepancies between previous data-sets:
 → Mainz and PRad/JLab: Q2 > 0.01 GeV2/c2
• Sufficient range to determine radius: → Inconsistency with other radii extractions
 → Aimed precision of below 1%
 → Aimed Q2 range: 0.001 - 0.04 GeV2/c2 • Goal: Understanding of this situation

 rp = 0.831 fm
 PRad

 J. C. Bernauer
 Mainz

 COMPASS++/AMBER
 rp = 0.879 fm
 rp = 0.841 fm

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 19

Layout of Proton-Radius Measurement at CERN
Measurement of low-Q2 elastic-scattering

Detection of low-energetic recoil-protons and
scattered muons with small scattering-angle.

• Silicon trackers along large leaver-arm to
 measure small scattering-angles

 CERN-SPSC-2019-022; SPSC-P-360
• Fiber tracker timing and trigger

• TPC as an active target with the ability to
 measure the low-energetic recoil-proton

• New continuously-running DAQ
 3.0 m 2.5 m 3.0 m

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 20

Layout of Proton-Radius Measurement at CERN
Advantages of using the COMPASS spectrometer

Measurement of muon momentum and understanding of background.

 CERN-SPSC-2019-022; SPSC-P-360

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 21

Layout of Proton-Radius Measurement at CERN
Advantages of using the COMPASS spectrometer CERN-SPSC-2019-022; SPSC-P-360

• COMPASS spectrometer
 → Momentum measurement of scattered muon
 → Radiative background using electromagnetic calorimeter
 → Muon identification with muon filter and hodoscope

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 22

Challenges for Proton Charge-Radius Measurement
 Novel measurement using TPC and tracking

 Combination of active-target TPC measurement • DAQ:
 with tracking and a new DAQ system. → completely new system
 Hardware:
 Software:
 • TPC:
 → Beam-induced ionisation noise • Event reconstruction:
 → Pressure and beam rate dependence → Tracking and vertexing efficiency
 → Read-out segmentation / electronic noise → Real data with new DAQ and detectors
 → Drift time control (pressure and temperature) → Tracking and vertexing efficiency

 • Fiber Tracker: • Event matching:
 → Beam + halo influence → Beam rate dependence / efficiency
 → Possible trigger logic (HW/HLT) and efficiency → TPC Read-out segmentation
 → Alignment control
 • Monitoring hardware and data quality:
 • Silicon Tracker: → Statistic and data quality essential
 → Beam + halo influence → Online monitoring / reconstruction
 → Infrastructure / cooling
 → Alignment control All of those need and will be
 → Hit timing
 addressed during pilot run in 2021

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 23

Preparation and Pilot Run in Phase I (2021)
Development schedule for 2021/2022

Very tight schedule in terms of time, funding and man power. Nevertheless,
developments are progressing on all subjects.

• Preparation along 2021:
 → Implementation and testing of continuously running DAQ system
 → Implementation and test if quality assurance
 → Detector tests: new silicon detectors, new fibers and modified IKAR TPC

• Goals until end of 2021 - pilot run:
 → New continuously running DAQ system
 → Quality assurance (alignment and environment control + corrections)
 → Helium tubes + infrastructure
 → 4x prototype silicon tracking-detectors
 → 3x new fiber trigger (partially equipped)
 → Down-scaled TPC (modified IKAR TPC with readout + electronics)
 → Evaluate tracking, vertexing and hit/track matching performance

• Until beginning of 2022:
 → Construction of final silicons, fibers and final TPC

COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 24

Pilot-Run - Infrastructure (EHN2-WG)
Test location at current CEDAR position

20 days of dedicated pilot-run as preparation for 2022 data taking.

 Together with D. Banerjee and J. Bernhard
COMPASS++/AMBER – PCRM 29.9.2020 Jan Friedrich 25