Quest to Upgrade the CMS Hadronic Calorimeters

Ugur Akgun

Take a massive explosion to create plenty of stardust and a raging

heat.

Simmer for an eternity in a background of cosmic microwaves.

Let the ingredients mix and leave to cool.

Serve cold with cultures of tiny organisms 13.7 billion years later.

To understand the basic ingredients and the ‘cooking conditions’ of the cosmos, from the beginning of time to the present day…

Particle physicists have to try and reverse-engineer the ‘dish’ of the Universe…

Within the complex combination, cryptic clues hide the instructions for the cosmic recipe…

2

The Standard Model of Particle Physics

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Mat

ter

Par

ticl

es

Force

Particle

s

Over the past 100 years, observed many new particles coming down from the sky, and produced in accelerators… They come in two categories: electron-like (lepton) and proton-like (containing quarks) Nature has made 3 copies of everything: of leptons and of quarks. WHY?

Open Questions of Standard Model

Higgs Boson: Generation of mass

Dark matter + Dark Energy: 96% of universe

Absence of antimatter: CP violation

Unification of Fundamental Forces

Supersymmetry

Why gravity is so weak? – Extra dimensions

How about blackholes?

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5

The tools of the trade

2. Detectors : gigantic

instruments recording the

particles spraying out from the

collisions.

1. Accelerators : powerful machines

capable of accelerating particles up to

extremely high energies and bringing

them into collision with other particles.

3. Computers : collecting, stocking,

distributing and analysing the

enormous amounts of data produced

by the detectors.

4. People : Only a collaboration of

thousands of scientists, engineers,

technicians and support staff can

design, build and operate these

amazing machines

W. Clarida 6

Lake Geneva

Large Hadron Collider 27 km circumference

CMS

ATLAS

LHCb

ALICE

LHC Experiments

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8

The Environment: Collisions at LHC

Triggering on di-muons at 1032-1033 with CMS

Dimuon mass distribution obtained from overlapping several trigger paths.

X(3872) status brief summary

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Belle m=3871.61±0.16±0.19 MeV/c2 (CDF)

I=0, no evidence for charged partners. (BaBar)

ππ system favors ρ0 (Belle, BaBar)

JPC status and controversial:

1++ favored (Belle)

1++ or 2-+ (CDF)

C=+ determined by J/Ψγ decay (BaBar, Belle)

2-+ favored, cannot rule out 1++ (BaBar)

Currently QCD does not allow for a meson or baryon with

these characteristics.

J/ψ π+π- Mass Spectrum

• The mass spectrum is fitted with unbinned log-likelihood

• Mass values are compatible with the PDG values

• CMS fit results:

– mΨ(2S)= 3685.9 ± 0.1 MeV

– σ1 Ψ(2S)= 8.1 ± 0.6 MeV

– σ2 Ψ(2S)= 3.3 ± 0.3 MeV

– mX(3872)= 3870.2 ± 1.9 MeV

– σX(3872)= 6.3 ± 1.3 MeV

• PDG values:

– mΨ(2S)= 3686.09 ± 0.04 MeV

– mX(3872)= 3871.56 ± 1.9 MeV

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Compact Muon Solenoid (CMS)

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Slice of CMS

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Hadronic Forward Calorimeter Upgrade Project

2011 - 2012

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HF in Cavern

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HF Wedges

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HF Readout Box, PMT Board & PMT

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Abnormal Events at HF

Test beams showed some abnormally high signal

events at HF wedges.

“Design, Performance, and Calibration of CMS

Forward Calorimeter Wedges” Eur. Phys. J. C53, 1, 2008

"Beam Test Results for the anomalous Large Energy

Events Removal in Hadronic Forward

Calorimeter", CMS DN-2009/005

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Abnormal Events at HF

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“Normal” Events at HF

Signal Arrival Difference

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Pulse Width Difference

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“A Novel Method to Eliminate Muon Events on HF PMT Windows”, CMS DN-2009/014

Normal HF Signal Muon Signal on PMT

Pulse Width Difference U. Akgun et al. “A Novel Method to Eliminate Muon Events on HF PMT Windows”, CMS DN 2009/014

Normal HF Signal

Muon Signal on PMT

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New Generation PMTs

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Single Anode Square PMT

R7600U-200

Four Anode Square PMT

R7600U-200-M4 R9880U-110

mini PMT

PMT Type Photocathode Typical Gain Name

R7600U-200 Ultra Bialkali 43 Single Anode PMT

R7600U-100-M4 Super Bialkali 35 Four Anode PMT

R7600U-200-M4 Ultra Bialkali 43 Four Anode PMT

R8900U-100-M4 Super Bialkali 35 Four Anode PMT

R9880U-110 Super Bialkali 40 miniPMT

R7525 Bialkali 25 HFPMT

Quantum Efficiency (max.) (%)

1x106

1.3x106

1.3x106

1x106

2x106

5x105

Muon Response on PMT Window

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Cherenkov Detection by new PMTs

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"Study of Various Photomultiplier Tubes with Muon Beams And Cerenkov Light Produced in Electron Showers", CMS NOTE 2010-003, Journal of Instrumentation P06002, 2010

Neutron Interaction with Borosilica PMT Window

The cross section for boron capturing neutrons increases drastically with lower neutron energy, reaching to 3980 barn at thermal energy level ~0.025 eV. The reaction leads to Li with the excited state 94% of the time, where the remaining 6% would be ground state Li.

Boron and thermal neutrons interact in two possible 10B5 + 1n0 --> 7Li3 + 4α2 (Q value = 2.792 MeV, ground state) 10B5 + 1n0 --> 7Li3

* + 4α2 + γ (0.48 MeV) (Q value = 2.310 MeV, excited state)

Thin glass – metal envelope Hamamatsu R7600-200-M4 interaction rate is 3 x10-6

Thicker glass - glass envelope Hamamatsu R7525-HA interaction rate is 3 x10-4

U. Akgun et al. "Boron and thermal neutron interactions on borosilica window

photomultiplier tubes", Journal of Instrumentation P08005, 2010

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Neutron Test Setup

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The University of Iowa Positron Emission Tomography (PET) center compact medical cyclotron, a cyclic accelerator, is used as the neutron source.

The 18F production runs, with an 18O target, are used as the neutron beam in this study;

18O8+ p 18F9 + n (14 MeV)

The produced 14 MeV neutrons are emitted with a rate of 1010 neutrons/s in 4π direction.

PMT Test Laboratories in Iowa and Coe

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• 3 dark boxes • VME and CAMAC DAQ systems • Computer controlled XY scanner and n.d.f. wheels • 3 picoammeters • 3 digital scopes • UV and visible power meters • UV and Blue LED light source • 2 nitrogen lasers •Nitrogen Dye Laser • 2 dark boxes has DC light source (tungsten light bulbs) • Optical table with all mounts and stands • Pico second LED pulsers and 1 double pulse generator

HF PMT Test Data

• On Every PMT:

– Rise Time

– Negative Pulse Width

– Transit Time

– Transit Time spread

– Single Pulse Linearity

– Anode Dark Current

– Cathode Dark Current

– Gain vs HV

– Cathode Luminous Sensitivity

– Anode Luminous Sensitivity

– Cathode Blue Sensitivity

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• One PMT on every Batch:

– Cathode surface non-uniformity

– Double Pulse Linearity

– Single photoelectron resolution

– Anode Cross-talks

– Afterpulse measurements

• One time tests:

– PMT Lifetime

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0.4-0.5

0.3-0.4

0.2-0.3

0.1-0.2

0-0.1

CMS Hadronic Endcap Calorimeter Upgrade Studies

Swords to Ploughshares

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Current Design: “Scintillators”

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• Megatiles of large scintillator sheets divided into components. They are inserted into 9mm thick spaces between absorbers.

• Light emission from tiles wavelength: λ=410-425 nm.

• Signal collected with wavelength shifting fibers absorbs blue, emit at λ=490 nm • For the barrel and endcap detectors, the photosensors are hybrid photodiodes (HPDs) are used.

FLUKA Simulations

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Simulation studies show that the scintillators are not going to be radiation hard for high Luminosity LHC runs.

Outline We are proposing to replace HE scintillators with quartz plates for

high luminosity LHC runs. • 0th Phase of R&D

– Show that Quartz is Radiation Hard

• 1st Phase of R&D – Cherenkov Light Collection from Quartz Plate – Tests of WLS fiber Embedded Quartz Plate Calorimeter

• 2nd Phase of R&D – Light enhancement tools: ZnO, PTP – Tests of PTP Deposited Quartz Plate Calorimeter

• 3rd Phase of R&D – Alternative readout options: SiPM – Radiation Hard WLS Fiber options

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Quartz Radiation Damage Studies We tested more than 10 different types of quartz with electron, proton and

neutron irradiation. Polymicro quartz core, quartz clad fiber with a polyamide buffer looks promising.

Electron Irradiation Tests: Dumanoglu et al. “Radiation-hardness studies of high OH content quartz fibres irradiated with 500 MeV

electrons” Nucl. Instr. Meth. A 490 (2002) 444-455

Proton Irradiation Tests:

Cankocak et al. “Radiation-hardness measurements

of high OH content quartz fibres irradiated with

24 GeV protons up to 1.25 Grad“

Nucl. Instr. and Meth. A 585 (2008) 20–27

Neutron and Gamma Irradiation Tests:

U. Akgun et al. “Radiation Damage in Quartz Fibers

Exposed to Energetic Neutrons”, in preparation

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Cherenkov Light Collection in Quartz

• Good : Quartz is radiation hard. • Bad : We have to collect cerenkov photons. Very little light !! At fixed angle. • Strategy: Go deep in UV to collect Cerenkov photons. • We did R&D studies on

– WLS fiber geometry • Cerenkov light collection, uniformity, and efficiency

– Wrapping material reflectivity tests, Aluminum, Tyvek, HEM, Mylar.

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Wavelength Shifting Fibers in Quartz

We showed that Cherenkov light collection inside the quartz is feasible with UV absorbing WLS fibers.

F. Duru et al. “CMS Hadronic EndCap Calorimeter Upgrade Studies for SLHC - Cerenkov Light

Collection from Quartz Plates” , IEEE Transactions on Nuclear Science, Vol 55, Issue 2, 734-740, 2008.

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QPCAL with WLS Fibers

We built and tested “WLS Fiber Embedded Quartz Plate

Calorimeter Prototype” U. Akgun et al., "Quartz Plate Calorimeter as SLHC Upgrade to CMS Hadronic Endcap

Calorimeters", XIII International Conference on Calorimetry in High Energy Physics,

CALOR 2008, Pavio, Italy, May 2008, J.Phys.Conf.Ser.160:012015, 2009

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Radiation Hard Wavelength Shifters Since the WLS fibers are not radiation hard, we tried radiation hard

light enhancement tools (pTp, and ZnO) with quartz.

U. Akgun et al., "P-Terphenyl Deposited Quartz Plate Calorimeter Prototype", IEEE Nuclear Science Symposium Conference, Dresden, Germany, 19-25 October 2008

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Covering Quartz Plates with pTp and ZnO

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We evaporated PTP and RF sputtered ZnO over quartz plates

QPCAL with pTp We built and tested “PTP Deposited Quartz Plate

Calorimeter” U. Akgun et al. "CMS Hadronic Calorimeter Upgrade Studies - P-Terphenyl Deposited

Quartz Plate Calorimeter Prototype ", APS 2009, Denver, CO, USA, May 2009 B. Bilki et al. “CMS Hadron Endcap Calorimeter Upgrade Studies For Super­LHC”, CALOR

2010, Beijing, China, May 2010

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QPCAL with pTp – EM Mode

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We can use combination as radiation hard CMS Endcap Calorimeter (EE + HE). U. Akgun et al. “CMS Hadronic Endcap Calorimeter Upgrade Studies for SLHC P-Terphenyl Deposited Quartz Plate Calorimeter Prototype'‘ IEEE Transactions on Nuclear Science, Volume 57, Issue 2, 754-759, 2010

Alternative Readout We constructed and tested alternative readout options

from pTp deposited quartz plates:

APD, SiPM, PIN diode.

They are not very effective and most importantly, the APD and SiPMs are not radiation hard enough for us.

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Microchannel PMT

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Fast response time, high gain, small size, robust construction, power efficiency, wide bandwidth, radiation hardness, and low cost.

8 stage device is assembled from micro-machined dynodes which exhibits a gain of up to 2-4 per stage on single stage.

The total thickness is less than 5 mm. 8x4 pixel micro-dynode array is shown

New Hamamatsu PMTs • During our HF Upgrade studies we extensively tested Hamamatsu 7600

series.

• Ultra Bialkali will make them better than any other option.

• Mashed architecture makes it B field hard. With no shielding it deviates only 2.5% at 200 Gauss.

• We also built mu shields for these PMTs. They’ll function in much higher B Fields.

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New Radiation Hard APD

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We are in contact with J. Russ on new radiation hard APD option. The APD has low response wavelength, and it is radiation hard up to 1015 neutrons. We are planning to test them on quartz plates, ASAP.

Radiation Hard WLS Fiber We Develop Radiation Hard Wavelength Shifing Fibers: Quartz

fibers with PTP/ZnO covered core.

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We built a radiation hard WLS fiber prototype. Deposited pTp on the stripped region, on both face. Then the whole ribbon will be sandwiched between quartz plates.

Radiation Hard WLS Fiber

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We prepared a “homemade” rad-hard WLS fiber. We stripped the plastic cladding from QP fibers for “middle 20 cm” portion of 60 cm fibers. This unit was tested with 80 GeV electron shower. The red line show the pedestal. With a very simple prototype we collected substantial signal. We try to optimize the model using Geant4 simulations.

Scintillating Glass

• What’s out there – Lithium, cerium, niobium, and fluorozirconate doped

glass scintillators. The base material is usually a borosilicate (Pyrex)

– Applications include: • thermal neutron detection, neutron radiography,

crystallography, oil well logging, and alpha, beta, and gamma detection in harsh environments

• Possibilities – Lithium scintillators are not

radiation hard

– Europium scintillators can have fast

decay times 51

Conclusion HF upgrade of all PMTs will be completed in 2012, and the electronic

readout channels will be upgraded before 2015. Multi-anode readout will solve the noise problem due to stray muons and neutrons.

We have two “viable” options for HE Upgrade, these can also be applied to EE region with 2 cm absorber thickness.

Will read signal from PTP deposited plate, directly. This will require radiation hard detector: Hamamatsu 7600 series, or multi channel

PMT

The current technology of APD and SiPM is NOT enough.

New radiation hard APD option needs to be tested.

Will use WLS fibers This requires rad-hard WLS fiber, which DOES not exist.

We built a primitive prototype with PTP, it is promising. Need R&D on PTP, ZnO deposition on quartz fibers. Scintillating glass, and Sapphire fibers are other options.

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