The Liquid Argon Time Projection Chamber (LAr TPC) in

The Liquid Argon Time Projection

Chamber (LAr TPC) in Neutrino

Physics Bruce Baller

Fermilab

1SLACInstrumenta0onSeminar‐Feb10,

2010

Outline

•  LAr TPC basics •  History •  ICARUS •  Long Baseline Neutrino Experiment (LBNE) •  R&D in the U.S.

– Argon purity – On-wire electronics – LAr TPC operation

•  Summary

2SLACInstrumenta0onSeminar‐Feb10,

2010

SLACInstrumenta0onSeminar‐Feb10,2010 3

fromMitchSoderberg

ppm in air 0 12 1 9500 0.1


NeedextremelygoodLArpurity,lowconvec0veflow

2.5m1.6ms

History •  1968 - Alvarez proposed the use of liquefied

noble gases as detector media •  1970’s

–  LAr & LXe calorimeters in use, LAr TPC prototypes

– Willis, Chen, Radeka, Gatti, Rubbia contributions

•  1977 – Carlo Rubbia proposed the LAr TPC •  1985 – ICARUS (T600) proposal at Gran Sasso

–  1993 – Cosmic rays tracked with a 3 ton LAr TPC

5SLACInstrumenta0onSeminar‐Feb10,2010

ICARUSpioneerinLArTPCtechnologyTheU.S.LArTPCprogramusesICARUSasafounda0on


ICARUS T600

1.5m 1.5m


2007-2010 Activities – ICARUS Collaboration

The preparation of ICARUS has been completed The vacuum pump-down in progress. At 10-4 Torr LAr filling planned for Feb 28 – mid March

CNGS run starts in April – 6 months (~1k events?)

Picturescircalate2009

CourtesyofD.Cline

T600 surface test in Pavia - 2001

e.m. shower

e.m. shower

µ decay

stopping µ with decay electron

hadron cascade

nuclear interaction

e.m. showers

CourtesyofD.Cline 8SLACInstrumenta0onSeminar‐Feb10,2010


LeadingtoLAr20



Fermilab

DUSEL

LBNE - Long Baseline Neutrino Experiment $900M on 1 slide

•  10 year project •  CD-0 granted in mid January •  CD-0 Scope

–  700kW proton beam (upgrade path to 2MW) –  Neutrino beam (0.5 – 4 GeV) –  Near detector –  1000+km baseline –  2 x 100kton Water Cherenkov Equivalent far

detectors, for instance •  100kton WC •  16.7 kton LAr TPC LAr20

•  CD-1 review December 2010


Isthistechnologyready?Isitcostcompe00ve,safe?

17m

~3m

19m

LAr20Concepts

•  300’/4850’underground

•  Membrane/modularcryostat–  ~20,000m3

•  TPCconfigura0on•  Lightcollec0onforsupernova&protondecay

•  FNALbeamtrigger


Main Challenges for Massive LAr TPCs

  LAr Purity in large industrial vessels   Materials qualification: test stand measurements   Purification techniques for non-evacuable vessels

  Large scale low noise readout (~500k channels)   On-Wire (cold) electronics and signal multiplexing   Test stands

  Underground issues: safety, installation   Cost


ICARUS Purification Steps •  Use high vacuum standards in construction and

cleaning •  Evacuate the cryostat to < 10-3 mbar to remove

contaminants •  Cool quickly and fill with LAr to minimize

outgassing •  Re-liquefy gaseous argon (GAr) boil-off and

purify before returning to the main volume •  Recirculate and purify the main LAr volume if

there is significant contamination at filling or due to an upset condition


Expensivecryostat

Expensiveforalargecryostat

Isthisneeded?FNALR&DMaterialsTestStand

ICARUSPurifica0onExperience


1.5xtheICARUSdri[0me

Purity Requirement •  Electro-negative

contaminants –  O2 & water

•  If 20% signal loss is OK for 2m drift –  Need 5 ms electron

lifetime ~60 ppt O2 contamination

–  LAr supply typical 1 ppm

•  N2 < 1 ppm for light collection

SLAC Instrumentation Seminar - Feb 10, 2010 17

Purification Methods & Instrumentation

•  Three stage – Molecular sieve removes water – Copper removes oxygen – Active carbon removes hydrocarbons – In-place regeneration

•  Commercial in-line instrumentation – 300ppt sensitivity

•  In-line purity monitor (ICARUS)



PrMscopesignal PrMautoma0onso[ware

PurityMonitor–Dri[Cell

Materials Qualification

•  No published results on materials effects on electron lifetime from ICARUS or other exps – Materials Test Stand

•  ICARUS experience: detector materials outgas contaminants despite the care taken in construction and evacuation – Materials Test Stand


Test Stands (Bo & Luke)


Stephen Pordes (FNAL)


Pordes,Kendziora,Tope(FNAL)

Materials Test Stand Features •  Can insert materials into known clean argon •  Can insert materials after purging only or after

pumping on them. •  Can position materials into liquid and into ullage

with range of temperatures •  Can insert known amounts of contaminant gases •  LN2 condenser can maintain liquid for long

studies (weeks) •  Internal filter-pump can remove contamination

introduced by materials – 2hr cycle •  Sample points at Argon Source, after single-pass

filters, in cryostat gas and liquid


Materials Test Run


Cold pre-amp

Cables & Cable ties

T962DecouplingBoard

Summary of Results


Water Effects - 1


FR-4 based circuit board – from Argonlock with evacuation

Little change in H20 reading and little change in lifetime

Water Effects - 2


FR-4 based circuit board – from Argonlock with purging only

Significant change in H20 reading and significant reduction in lifetime

Water is the dominant contaminant, not O2, for lifetimes of 5 – 10 msec Not a contaminant if the materials containing it are maintained at ~100K

Purification in a Massive LAr TPC

•  Contaminants are in the vapor – Remove gas from top of cryostat continuously

•  Removal rate proportional to the partial pressure difference of the water concentration in materials and the surrounding atmosphere – Hot dry argon gas should be as effective as

evacuation in removing water (and O2) •  Liquid Argon Purity Demonstrator (LAPD) will

test this concept


LAPD •  Commercial SS tank &

cryo system •  Steps

–  Remove air w gaseous argon (GAr) piston

–  Flush w GAr •  2.6 volumes 100 ppm

–  Heat to 50oC –  Recirculate GAr through

purification system –  Cool-down and fill w LAr –  Check purity

•  Results in Fall 2010


10 feet

Brian Rebel, Rob Plunkett (FNAL)

LAr20 Membrane Cryostat Option

•  Attractive if evacuation is not necessary –  Efficient use of the excavated cavern volume –  Design used in LNG tankers of volume 10x LAr20 –  240 tankers in service


On-Wire Electronics •  Large detector (20m x 20m) long cables to

preamplifiers high noise on-wire electronics –  Identify a CMOS process suitable for cryogenic

operation that will be available in 5 years •  Work by Radeka, Rescia (BNL), Yarema, Deptuch

(FNAL), Edmunds (MSU) –  New collaboration with Cressler (Georgia Tech)

•  Other activity not in this talk –  Marvin Johnson (FNAL) exploring the limits of

warm readout electronics with low capacitance woven cable



Signal cable lengths increasing to >10-20 meters for detector fiducial volume > 1kton resulting in high capacitance and high noise

Cold electronics decouples the electrode and cryostat design from the readout design: noise independent of the fiducial volume

Cryostat Design: “Warm” vs “On-Wire” Electronics

CablesoutgasinwarmGAr


u

v y

U

V

Y

2 6 4 Time (µs)

Dri

ft D

ista

nce

(cm

) Charge Signal Formation

Current Out of Wire

Induction (small, bipolar)

Induction (small, bipolar)

Collection (large, unipolar)

Induction by and

Collection of electrons on

wires


u

v

y

Inclined Tracks

Waveform shape varies with the inclination angle


Noise vs T in CMOS: Preliminary Test Result Exis)ngASIC,notdesignedforLAr

T[K]

ENC[erms]

CMOS in LAr has less than half the noise as that at room temperature

ENCvs.T(Cd=100pF,0.5µspeaking0me)

LAr87K


• Degrada'onisduetoimpactioniza'on

• chargetrapinoxide,interfacegenera0on→shi[inVthandgm

• Substratecurrentisamonitorofimpactioniza'on

• increaseswithdrainvoltage• ishigherinshortchanneldevices• hasamaximumatVgs≈Vds/2

• increasesasthetemperaturedecreases

CMOS Reliability at Cryogenic Temperatures – Basic Mechanism

• Commercialtechnologiesarerated10yearslife0me(10%shi[)inworstcasecon0nuousopera0on:T=220K,L=Lmin,Vds=nominalVdd,Vgs≈Vds/2)

• AcceleratedtestsatincreasedVdsallowextrapola'onoflife'me J.Cressleretal.


•  Reliabilityatlowtemperaturecanbeguaranteedby:

1.  decreasingVds(i.e.decreasingthesupplyvoltage)

2.  decreasingVgs(i.e.decreasingthedraincurrentdensity)

3.  increasingL(i.e.non‐minimumchannellengthdevices)

•  Designguidelines:

1.analogcircuits

•  operatedevicesatlowcurrentdensity

•  usenon‐minimumchannellengthL

2.digitalcircuits

•  operatedevicesat2/3ofnom.Vdd

•  usenon‐minimumchannellengthL

CMOS Reliability at Cryogenic Temperatures – Design Guidelines

J.Cressleretal.Accelerated tests will be performed to guarantee > 20 yr lifetime at 90 K (operated at Vdd and max. current continuously)




D0 spares 6% overshoot in ArgoNeut

Edmunds (Michigan State)



Induction Plane

Collection Plane


Collection Plane


Largeenergydeposi0onlargeovershoot

Induc0onPlane

Collec0onPlane

Waveform Deconvolution


ADCShaperOut=WireSignal⊗Preamp⊗Shaper

Convolu0on

ADC=F‐1{(F(WireSignal)*F(Preamp)*F(Shaper)}

FourierTransform

De‐convolu0on

WireSignal=F‐1{Filter*F(ADC)/(F(Preamp)*F(Shaper))}

Remove electronics effects Band filter to remove coherent noise, etc

Not needed with careful electronics design


Overshoot different for different shaper cards

Collec0onPlane

Deconvolution Results Very Preliminary

Collec0onPlane

A Deconvolution Trick


Convert bi-polar induction plane waveform to uni-polar collection plane waveform Only one hit reconstruction algorithm needed!

WireSignal=F‐1{Filter*F(ADC)*F(Col) (F(Preamp)*F(Shaper)*F(Ind))}

Collec0on(Induc0on)planewaveform1MIPresponse


Run 561 Event 220 Induction Plane Channel

Raw Data

Std deconvolution kernel

Deconvolute w Trick kernel (needs filter tuning)


Summary

•  Noble liquids: 40 years of R&D •  LAr TPC: 30 years of R&D •  ICARUS pioneered and mastered this

technology •  The U.S. is a recent immigrant in the field

– World class R&D contributions applicable to MicroBooNE, LAr20, GLACIER and potentially DM exps

•  On-going R&D will confirm the viability of this technology for LBNE in the next few years


BackupSlides


ArgoNeut Purity History



ENC vs Sense Wire resistanceSSsensewire150µm(36ohm/m)andCu+AuplatedSSwire(3ohm/m)


kT = e/Dm TTRAN = 480K TLONG = 200K

(2.5 m)

Diffusion, drift velocity, and the time scale of induced signals

•  The time scale of the detector signals is determined by the wire plane spacing and the electron drift velocity (~1.5 mm/µs at 500 V/cm).

•  Diffusion smoothes out the high frequency components due to the coarse sense wire grid structure which don’t include any useful information. Diffusion broadening of the signal ~ 0.6 µs rms.


•  A 3mm MIP track will deposit 210keV/mm x 3mm /23.6eV/e = 4.3fC

•  After a 1/3 initial recombination loss: ~2.8fC

•  It is expected that the TPC design will maximize the drift path to equal or exceed the charge life time, thereby reducing the signal to 1/e≈0.368

•  The expected signal for 3mm wire spacing is then ≈1fC=6250 electrons,

… and for 5mm, ≈104

electrons, for the collection signal •  The induction signals are smaller

Signals in LAr TPC

Induced Current Waveforms on 3 Sense Wire Planes:

Charge signal:


Signalfor

(1/edri0)

3x35x5

104e

Signalfor

(1/edri0)

3x35x5

104e

Noise vs Sense Wire and Cable Length

Warm Electronics

On-wire Electronics Small TPC

BigTPC


A Functional Outline of a Multiplexed Readout Chain for Very Large LAr TPCs

A Functional Outline of a Multiplexed Readout Chain for Very Large LAr TPCs. Multiplexing will be performed in two steps at appropriate locations within the cryostat. A CMOS, or a BiCMOS technology with circuit design and operating conditions for long term operation in LAr will be used. A preliminary goal is multiplexing in two steps by 16 x 8=128. Power dissipation has been estimated to be ≤10mW/signal wire.

Hit Shape Fitting Two Track Separation- MC


100%efficiencyin2tracksepara0onforsep>4mmArgoNeutsimula0on

Documents

The Liquid Argon Time Projection Chamber (LAr TPC) in