HCAL-J: a Hadron Calorimeter for the Hall A ...newcleo.unime.it/Events/DHF2014/talks/Bellini.pdfVincenzo Bellini International Conference Dark Matter, Hadron Physics and Fusion Physics

HCAL-J: a Hadron Calorimeter for the Hall A

SuperBigByteSpectrometer at JLabVincenzo Bellini

International ConferenceDark Matter, Hadron Physics and Fusion Physics

Capo Peloro Resort Hotel – Messina (Italy)September 24-26, /2014

INFN & Dipartimento di Fisica e Astronomia,University of Catania, Italy

On behalf of the Hall A Collaboration

V. Bellini and INFN/CT Hall A Collaborators

DMHPFP Messina September 25, 2014 1

Outline

1. Nucleon form factor studies at JLab.2. The SBS Spectrometer of the Hall A Collaboration.3. The HCAL-J Calorimeter ( Consortium CMU-INFN/CT-JLab)4. Physics Motivation.5. Design.

i. Past R&D

ii. DOE Review

iii. Final Plan


DMHPFP Messina September 25, 2014

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Nucleon Form Factor Studies at JLab



3

JLab CEBAF electron beam in 2014


Hall A has been the first hall to get the beam



4

Challenges at high Q2


For a double-polarization experiment with a recoil polarimeter

For a double-polarization experiment with a recoil polarimeter



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Hadron CalorimeterHCAL-JCarnegie Mellon INFN Catania JLab

GEp Electron Calorimeter

Ancillary Equipment:




6

Hall A 2014 Experimental Setup




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Hall A 2014 Experimental Setup

- 48D48 – 46 cm gap, 2.5 Tesla*m- Solid angle is 70 msr at angle 15°- GEM chambers with 70 μm resolution- momentum resolution is 0.5% for 5 GeV/c- angular resolution is 0.3 mrad



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Optimizing acceptance and rates


The Super Bigbite magnet is optimized for FF measurements.

• Single dipole provides adequatemomentum resolution (~1%) andlarge solid angle (~70 msr)acceptance. (Also true of originalBigBite magnet).• Vertical aperture well matched toelectron arm while stillappropriate for ΔQ2/Q2~ 0.1.• Cut in yoke permits operating atsmall angles where the recoil isgoing.



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Optimizing detectors for luminosity


Gas Electron Multiplier (GEM) technology for tracking ensures the ability to handle very high luminosity.



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Jlab experiments with SBS and HCAL

• GEP, GEN, GMN, SIDIS - approved• TDIS, DDVCS – under preparation



The SBS project is aiming at the Holy Grail in electron scattering instrumentation: the combination of large solid angle coverage at forward angles and the highest luminosity achievable with the upgraded 12 GeVCEBAF. The SBS consists of a transverse field dipole magnet equipped with high-rate GEM tracking detectors. Additional detectors, like calorimeters ( as HCAL) and Cerenkov counters will be used for triggering and particle identification

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An ongoing CMU/INFN/JLAB supported activity.

Requirements for the SBS experiments:• Match acceptance of SBS magnet/polarimeter• High threshold while maintaining high trigger

efficiency.• Goal: 95% efficiency: thresholds at 25% avg. signal.• Linear Energy Response

Time ResolutionRequired: TOF < 1.0 nsec (Goal: 0.5 nsec)

Angular resolution: 5 mrad

HCAL Hadron Calorimeter



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HCAL Design• The HCal is based on 288 cells of 15cm x15cm Fe-Scint cells

employing wavelength shifter readout through fast 2" photomultipliers (PMTs).

• The requirements for the HCAL to be used with the SBS have driven continued research and development (R&D) efforts in understanding the behavior of the COMPASS HCAL1 (simulation compared to measurement) as well as desired improvements.

• Most of the R&D activity has been aimed at improvements in timing, and a choice of PPO-only scintillator (matched to a WLS readout)

coupled to fast PMTs meets the goal of ~ 0.5 ns resolution.



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HCAL-J Design DeepeningsModular Design:

• 15 cm x 15 cm x ~ 1m modules• 40 Layers scintillator and iron per module• 288 Modules (36 tons)

Wavelength ShifterPMT

288 modules for JLab HCAL

Scintillators Absorbers

HCAL-J concept is based on COMPASS HCAL1, but…• Faster scintillator and wavelength shifter.• Wavelength shifter moved to center• Novel light guide.• 2 inch PMTs faster, better quantum

efficiency.

24 M

odul

es(3

60cm

)V. Bellini and INFN/CT Hall A Collaborators


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1

JLab kinematics

Technical Approach: Simulations extrapolate documentedCOMPASS high-energy performance to JLAB energies.

Spatial Resolution Simulation COMPASS performance: 1.5 cmSimulation: 1.5 cm at high energies

5 cm at JLab energiesHCAL positioned 17 m from target:5 cm / 17 m ‐‐‐‐> 3 mrad resolution

Trigger Efficiency SimulationsEnergy 2.5 GeV 5.0 GeV 10.0 GeV

Resolution: /E 48% 31% 22%

Efficiency at 1/4 mean signal: Neutrons

97.3% 99.2% 99.1%

Efficiency at mean signal: Protons

98.8% 99.6% 99.0%



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Status: Fall 2011

Most R&D at that time aimed to achieve timing goal

Time (ns)4 6 8 10 12

Trigger Time (ns)14 16

Counts

0

200

400

600

800

1000 FWHM = 1.12 ns = 0.48 ns

FWHM = 2.1 ns = 0.9 ns

Waveshifter decay time 8 ns --> 0.5 ns

PMT rise time10 ns --> 2.5 ns

Simulation using COMPASS parameters

Agreed withpublished COMPASSHCAL performance

Simulation using faster waveshifter dye and PMTs

Met SBS requirements

To be confirmed with prototype HCAL module

Trigger Time (ns)



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Summer 2013 Critical R&D Completed

• Contract with FNAL Scintillator ExtrusionFacility FNAL produces extruded scintillatorsamples. No “POPOP*” added to scintillator.PPO concentration varied.

• CMU tests FNAL PPO-onlyscintillator Coupled to BC-484 WLS(St. Gobain) Coupled to EJ 299-27WLS (Eljen)

• Acceptable attenuation lengths found Excellent timing and photo-electrons Optimal solution found:

0.5% to 1.0% PPO FNAL Scintillator BC-484 WLS

Selected combination meets required specification !



* POPOP or 1,4-bis(5-phenyloxazol-2-yl) benzene is a scintillator. It is used as a wavelength shifter.

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DOE Review November 4-5, 2013The panel is pleased to see the progress in the HCAL R&D efforts; the SBS experiments will benefit from an HCAL with improved performance. Construction of the prototype HCAL module (targeted for early 2014) is an essential step to understand how the singletile tests translate into a modular response. The prototype will also be invaluable in addressing various mechanical and optical issues of module construction vis-à-vis desired performance, as well as help in preparing a mass production protocol and QA procedure.Establishing an HCAL factory to produce ~300 modules (consisting of ~ 24,000 scintillator “pieces” among other things) is no small task and the projected completion rate of ~ 1/day may be a challenge to maintain. While many aspects of the overall design are finalized it is likely that the HCAL project would benefit from a “pre-production review” to help ensure successful completion.



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Decisions 2014: FINALIZED PLAN

• Geometry fixed

WLS moved from side to center of module Two (15 cm x 7.5 cm x 1 cm) scintillators/layer7.5 cm x 1 cm within capabilities of FNAL Minimizes light attenuation (WLS in middle)Eliminates small asymmetric tail in spatial resolution function

PMT Housing designed to allow fresh air to inhibit helium poisoning of PMTs

• FNAL will produce scintillators

FNAL will extrude 3.5 km of (7.5 cm x 1 cm) novel scintillator CMU will chop into 15 cm lengths. (Need about 24,000pieces) Cost ~$100k. (Compare to St. Gobain quote of $1,140k)

• INFN funded for WLS, Light Guide and Steel Absorbers production• Modules will be assembled at Carnegie Mellon University



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• Scintilllator• FNAL work supported by JLab• Manufacturing of Extrusion Die in progress• First extrusion run pending• CMU custom saw will be used for chopping

• Wavelength Shifters• INFN has ordered BC-484 WLS

• Light Guides• CMU optimized geometry• INFN overseeing production

• Iron absorbers• Quotes obtained by CMU

• Module housing and assembly• Prototype under production at CMU

Present Status:

Module prototype assemblyWill be filled with FNAL scintillator

o-ring sealed PMT bases

3D-printed light guide model



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HCAL_J Proto2 Completed

First WorkingPrototype

Proto2 50% loaded

50% loaded litwith UV LED

Setup for cosmics ( trigger paddles t op and bottom)

First pulses from cosmics



First 2014 PrototypeStatus:

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Entries 198 2 / ndf 17.22 / 14Constant 15.17 1.85Mean 0.1031 0.0322Sigma 0.3465 0.0326

4

THCal - Thit [ns]-4 -2 0 20

5

10

15

HCAL‐‐J Proto 2 Muon Time ResoluCon

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Entries 1982 / ndf Constant MeanSigma

17.22 / 14 15.17 1.85

0.1031 0.0322 0.3465 0.0326

HCal time resolution (time walk corrected)

Start‐‐Time corrected: σ = 310± 34 ps

( COMPASS HCAL measurement: σ = 620 ps )

First Proto2 cosmic rayTiming measurements



2014 SummerStatus:

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More details

• Proto2• Proto2 constructed with inferior light guide (about 40% of

adiabatic twisted strip light guide transmission)• Approximately 110 photo‐‐electrons for cosmic rays

• Injection Molded Light Guides• Samples received will not be adequate

• Surface quality good but…• Short bulk attenuation length• Large defects due to extraction points• Need more work

• Scintillator manufacturing (24,000 pieces)• All scintillators received• Cutt ing delayed due to lack of machinist• Production started

• Absorbers (15,000 ½ inch plates and 15,000 ¼ inch plates)• Vendor produced 15,000 ¼ inch plates (JLab)• Quotations asked for 15,000 half inch plates (INFN)



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Summary of the INFN Catania Contribution to the HCAL‐J Activity



• Development of the HCAL-J concept in the framework of theConsortium CMU/INFN-CT/JLab (working group of the Hall ACollaboration)

• Organize the construction:- procurement of the WLS’s- procurement of the LG’s

• Take charge of the PMT’s preparation

Current activity

Future Activity• Procurement of the iron absorbers• Continuing LG effort• Contributing to electronics setup of HCAL• Testing detector modules at Jlab• Procuring part of the Electronics modules

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VB1

Diapositiva 24

VB1 Vincenzo BELLINI; 01/07/2014

Documents

HCAL-J: a Hadron Calorimeter for the Hall A ...newcleo.unime.it/Events/DHF2014/talks/Bellini.pdfVincenzo Bellini International Conference Dark Matter, Hadron Physics and Fusion Physics