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1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Page 1: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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CF4 Scintillation and Aging

LIP - Coimbra

Luís MargatoAndrei Morozov Luís PereiraMargarida FragaFrancisco Fraga

Page 2: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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CF4 Scintillation

CF4 Primary ScintillationCF4 Primary Scintillation

► Produced by ionizing radiation

► Results were presented at Jornadas do LIP 2010 and published [Ref. 1] [Ref.2]

CF4 Secondary ScintillationCF4 Secondary Scintillation

► Light emission associated to electron multiplication induced by a high electric field.

► In order to have a high electric field in a well-defined region of space micropattern structures can be used e.g. MSGCs, GEMs.

CF4 ScintillationCF4 Scintillation

Photon yield for ultraviolet and visible emission from CF4 excited with α-particlesA. Morozov, M.M.F.R. Fraga, L. Pereira, L.M.S. Margato, S.T.G. Fetal, B. Guerard, G. Manzin, F.A.F. FragaNuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Volume 268, Issue 9 (2010) 1456-1459.

[Ref. 1]

Effect of electric field on the primary scintillation from CF4A. Morozov, M.M.F.R. Fraga, L. Pereira, L.M.S. Margato, S.T.G. Fetal, B. Guerard, G. Manzin, F.A.F. FragaNuclear Instruments and Methods in Physics Research Section A 628 (2011) 360-363.

[Ref. 2]

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 3: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Secondary ScintillationSecondary Scintillation

CF4 Scintillation

For detector design it is For detector design it is critical to know:critical to know:

Emission SpectraEmission Spectra

Light Yield Light Yield

Decay Time of the EmissionDecay Time of the Emission

Light Emission StabilityLight Emission Stability

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Images of the Sec. Scintillation from a Images of the Sec. Scintillation from a microtrip (readout by a CCD)microtrip (readout by a CCD)

Page 4: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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CF4 Scintillation

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 5: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Secondary Scintillation characterizationSecondary Scintillation characterization

Emission Spectra Emission Spectra (all corrections are applied)(all corrections are applied)

CF4 Scintillation

MSGC:MSGC:1- 5 bar CF41- 5 bar CF4

Secondary scintillation in CF4: emission spectra and photon yields for MSGC and GEMA Morozov, L M S Margato, M M F R Fraga, L Pereira and F A F FragaJINST 7 P02008, doi:10.1088/1748-0221/7/02/P02008

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 6: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Secondary Scintillation characterizationSecondary Scintillation characterization

Emission Spectra Emission Spectra (all corrections are applied)(all corrections are applied)

CF4 Scintillation

GEM:GEM:1bar CF41bar CF4

GEM: spectra show an apparent increase in the intensity of the emission originating from excited molecules (and a minor decrease in the emission from ions)

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 7: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Secondary Scintillation characterizationSecondary Scintillation characterization Light Yield Light Yield (Ph / el ratios)(Ph / el ratios)

CF4 Scintillation

Ph/el ratio as a function of pressure for a fixed MSGC charge gain of ~70; Two MSGCs (designated “M1” and “M2”) were used;

The average values of the ph/el ratios at each pressure are also shown with their full (statistical +systematic) uncertainties.

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 8: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

The St707 wide operating temperature range down to room temperature

Once the alloy is activated, reactive molecules such as O2, H2O, N2, CO, CO2 and H2 are adsorbed via a three steps adsorption mechanism: surface dissociation, surface sorption and bulk diffusion.

Purifier SAES St 707 (Custom Assembly)

8

Gas Purification SystemGas Purification System

Purifier SAES Microtorr MC1 – 905F

Clean gas cell

Two Types of Purifiers

− SAES St 707 getters (custom assembly)

− SAES MicroTorr MC1-905F

CF4 Scintillation – Gas Aging studies

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 9: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Experimental Setup

Time spectra was recorded by a start (Solid State Detector) and stop (PMT) technique

Study performed in the UV (220-450nm) and Visible (450-800nm):

An Am-241 alpha source was used for excitation

PMs were used in Single Photon Counting mode:

UV (220-450nm)

−PMT Photonis XP2020Q (HV=+2000V)−Broadband Filter: Schott UG11

Visible (450-800nm)

−PMT Hamamatsu R1387 (HV=-1170V)−UV-Block Filter: 450 nm cut-off

Study performed in the UV (220-450nm) and Visible (450-800nm):

An Am-241 alpha source was used for excitation

PMs were used in Single Photon Counting mode:

UV (220-450nm)

−PMT Photonis XP2020Q (HV=+2000V)−Broadband Filter: Schott UG11

Visible (450-800nm)

−PMT Hamamatsu R1387 (HV=-1170V)−UV-Block Filter: 450 nm cut-off

CF4 Scintillation – Gas Aging studies

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 10: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Effect of small admixtures of N2, O2, Dry Air, to CF4 Effect of small admixtures of N2, O2, Dry Air, to CF4

Visible component is affected by N2, O2 and Dry Air admixtures (different decay times)

Addition of N2, O2 and Dry Air seem to have a negligible effect in the Slope of the UV component

0 10 20 30 40 50 60 70 801

10

100

1000

CF4 (3 bar)

CF4 + 10mbar N

2 (3bar)

CF4 + 10mbar DryAir (3bar)

CF4 + 5mbar O

2 (3bar)

UV

<N

>

Time (ns)

0 20 40 60 80 100 1201

10

100

1000 Visible

~ 15 ns

~ 25 ns CF4 (3bar)

CF4 + 10mbar N

2 (3bar)

CF4 + 10mbar DryAir (3bar)

CF4 + 5mbar O

2 (3bar)

<N

>

Time (ns)

Time spectra (Primary Scintillation)Time spectra (Primary Scintillation)

UV UV VisibleVisible

CF4 Scintillation – Gas Aging studies

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 11: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Effect of small admixtures of N2, O2, Dry Air, to CF4 Effect of small admixtures of N2, O2, Dry Air, to CF4

Light output (relative intensity)Light output (relative intensity)

UV UV VisibleVisible

CF4 Scintillation – Gas Aging studies

0 10 20 30 40 50 600.0

0.5

1.0

UV:CF4 (3bar)

UV:CF4 + 10mbarDryAir (3bar)

UV:CF4 + 5mbar O

2 (3bar)

Inte

nsi

ty (

a.u

)

Time (min.)

0 10 20 30 40 50 600.0

0.5

1.0

CF4 (3bar)

CF4 + 10mbar DryAir (3bar)

CF4 + 5mbar O

2 (3bar)

Inte

nsi

ty (

a.u

.)

Time (min.)

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 12: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Purification effect of the contaminated CF4 Purification effect of the contaminated CF4 Two examples: Two examples: CF4 contaminated by Araldite CF4 contaminated by Araldite (());; CF4 with an admixture of N2.CF4 with an admixture of N2.

CF4 Scintillation – Gas Aging studies

0 20 40 60 80 100 120

10

100

1000Visible

CF4 (1.5bar)

CF4 + 20mbar N

2 (1.5bar)

Purification: St 707 Purification: MC1-905F

<N

>

Time (ns)0 20 40 60 80 100 120

10

100

1000Visible

CF4 (1.5bar)

CF4 + Araldite Contam. (1.5bar)

Purification: St 707Purification: MC1-905F

<N

>

Time (ns)

Admixture of N2Admixture of N2Contamination with AralditeContamination with Araldite

Time spectra (Visible component)Time spectra (Visible component)

After purification recovery to pure CF4 conditions (both purifiers)

For N2 N2 admixtures MC1MC1 purifier does does not recovernot recover to pure CF4 conditions

(() Araldite Rapid 2012) Araldite Rapid 2012

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 13: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Light output (relative intensity)Light output (relative intensity)

CF4 Scintillation – Gas Aging studies

Purification effect of the contaminated CF4 Purification effect of the contaminated CF4 Two examples: Two examples: CF4 contaminated by Araldite;CF4 contaminated by Araldite; CF4 with an admixture of N2.CF4 with an admixture of N2.

0 50 100 150 200 2500.0

0.5

1.0

Visible

Contaminated CF4

Pure CF4

Start Purification

CF4 (1.5 bar)

CF4 + Araldite contaminants (1.5 bar)

(Purification: SAES St 707)CF

4 + Araldite contaminants (1.5 bar)

(Purification: SAES MC1-905F)

Inte

nsity

(a.

u.)

Time (min.)

0 100 200 300 400 500 600 700 800 900 10000.0

0.5

1.0

Vis PMT: CF4+20mbar N

2 (1.5bar)

(MC1 905 and St 707 Purif.)

MC1 "Start"

St 707 "Start"

CF4+20mbar N

2 (1.5bar)

CF4 (1.5bar)

MC1 "Stop"

Inte

nsi

ty (

a.u

.)

Time (min.)

Contamination with AralditeContamination with Araldite Admixture of N2Admixture of N2

Effect of the gas contamination on CF4 primary and secondary scintillationL M S Margato, A Morozov, L Pereira, M M F R Fraga and F A F FragaNuclear Instruments and Methods in Physics Research Section A (in press)http://dx.doi.org/10.1016/j.nima.2011.10.033

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 14: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Emission Spectra and ph/el ratios of the Secondary Scintillation Emission Spectra and ph/el ratios of the Secondary Scintillation have been characterized:have been characterized:

Dependence on gain and pressure;

MSGC vs. GEM (1bar);

Gas aging studies:Gas aging studies:

Was shown that a time resolved technique can be used to study CF4 contamination and purification;

The visible emission of primary scintillations is more sensitive to gas impurities than the UV emission;

Aging studies for CF4 Secondary Scintillation have also been performed;

The Purifiers SAES St 707 and MC1-905F show ability to recover contaminated CF4 to fresh filling conditions, but the MC1-905F doesn't remove N2

► Study of the Decay Time of the CF4 Secondary Scintillation Study of the Decay Time of the CF4 Secondary Scintillation is being performedis being performed

CF4 Scintillation – Gas Aging studies

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 15: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Thank you for your attention

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 16: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Backup Slides

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 17: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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CF4 Primary Scintillation: CF4 Primary Scintillation: Time SpectraTime SpectraCF4 Primary Scintillation: CF4 Primary Scintillation: Time SpectraTime Spectra

Typical effective lifetimesTypical effective lifetimes

Effective lifetimes measured in the absence of electric field are: ~4 – 6 ns for the UV component

and ~8 – 16 ns for the visible component

Both the visible and UV time spectra show no indications of any slow (effective lifetime on the order of 100ns and longer) decay components.

CF4 Primary Scintillation

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 18: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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CF4 Scintillation – Gas Aging studies

Time spectra Time spectra (Visible component)(Visible component)

Kapton Contamination: After purification recovery to pure CF4 conditions (both purifiers)

Purifier: SAES St 707Purifier: SAES St 707Purifier : SAES Micro Torr MC1 905Purifier : SAES Micro Torr MC1 905

0 20 40 60 80 100 1201

10

100

1000

Vis: CF4 (1.5bar)

Vis: CF4 (1.5bar) + Kapton

Vis: CF4 (1.5bar) + Kapton (Purif. MicroTorr MC1-905F)

<N

>

Time (ns)0 20 40 60 80 100 120

1

10

100

1000

CF4 (1.5bar)

CF4 (1.5bar) + Kapton (run3)

Purif. SAES St 707

<N

>

Time (ns)

Purification effect of the contaminated CF4 Purification effect of the contaminated CF4 CF4 contaminated by KaptonCF4 contaminated by Kapton

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 19: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Secondary scintillation – Experimental SetupSecondary scintillation – Experimental Setup

A MSGC plate (ILL6C) was used for electron multiplication and secondary light production

Anode current read by an electrometer (Keithley 602):

Used to monitor the MSGC charge gain

Rate of coincidences between the charge and light signals:

Relative intensity of the secondary scintillation

Ratio of the coincidence rate to the secondary current:

Secondary scintillation intensity corrected for the gain fluctuations

CF4 Scintillation – Gas Aging studies

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal

Page 20: 1 CF4 Scintillation and Aging LIP - Coimbra Luís Margato Andrei Morozov Luís Pereira Margarida Fraga Francisco Fraga

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Secondary ScintillationPurification effect on CF4 Purification effect on CF4

0 20 40 60 80 1000

200

400

600

800

1000

CF4 (1 bar)Direct Filling

Filling through Purif. MC1Filling through Purif. St 707@300ºC

Isec

. (pA

)

Time (min.)

0 20 40 60 80 1000

1

2

CF4 (1 bar)

Direct FillingFilling through Purif. MC1Filling through Purif. St 707@300ºC

Lig

ht

ou

tpu

t /

Se

c. E

lect

ron

(a

.u)

Time (min.)

No significant difference in the emission intensity has been observed using these three filling conditions.

CF4 Scintillation – Gas Aging studies

0 20 40 60 80 1000

10

20

30

40

50

CF4 (1 bar)Direct Filling

Filling through Purif. MC1Filling through Purif. St 707@300ºC

Co

inci

den

ce R

ate

(s-1)

Time (min.)

Light outputLight output Anode currentAnode current

Luís Margato ([email protected]) Jornadas LIP, April 21-23, 2012, Lisbon, Portugal