Jul. 26th, 2004Brookhaven National Laboratory, USA

Yusa Muroya, Mingzhang Lin, Hokuto Iijima,Toru Ueda, Mitsuru Uesaka, Yosuke Katsumura

Nuclear Engineering Research LaboratoryUniversity of Tokyo, JAPAN

Performance and application ofultrafast pulse radiolysis system using

laser photocathode rf-gun combined with fs laser

PD1 PD2

FC

Shutter2(On/Off)

White light cell(D2O)

Fs laser(795nm)

Linac

Sample

BPF(400-1100nm)

Dielectric mirror795nm

Delay stage

Shutter1(On/Off)

• Optical delay system • Reference light for normalization of laser’s fluctuation• Elimination of noise by 2 shutters (beam on/off, laser on/off)

www.utnl.jp/~beamBeam-Material InteractionsMeasurement System

Laser(265nm)

www.utnl.jp/~beamBeam-Material InteractionsMeasurement System

795nm

White light cell

Beam splitter

BPFSample

PD1 PD2

www.utnl.jp/~beamBeam-Material InteractionsData Acquisition System

Shutter for pump

LabVIEW&

GPIB

PIN photodiode1

PIN photodiode2

Charge monitor

Optical delay stage

(1)linac/laser On/On Off/On On/Off Off/Off

Meas.1 Meas.2 Meas.3 Meas.4 O.D.calc.

Delay

(2)oscill.&com.(3)delay system

Pulse generator

Oscilloscope

Measurement scheme

GPIB

Shutter for probe

-0.020

0.020.040.060.08

0.1

0 50 100 150 200 250 300

H2O1M HClO4

Time /ps

30ps

-0.020

0.020.040.060.080.1

0 50 100 150 200 250 300Time [ps]

www.utnl.jp/~beamBeam-Material InteractionsPreliminary Pulse Radiolysis

00.040.08

0 10 20 30 40

9ps

In 1999

In 2002

00.20.40.60.8

1

0 50 100 150 200 250 300Inte

nsity

[a.u

.] Charge [a.u.]

I0

ICharge

1664Average9ps30psTime resol.

795nm (Fundamental)Wavelength

0.8-1.0nC4mm3ps

0.8-1.0nC4mm7ps

ChargeBeam sizePulse width

5 mm20 mml / mmH2OH2O&1M H+

Condition

Results- O.D. still low

www.utnl.jp/~beamBeam-Material InteractionsImprovement : dose increase & λ extend

Time resolution vs. dose(1) 2~3ps : pulse width (EB)(2) 100fs : pulse width (laser)(3) <1ps : synch.(4) 5ps /5mm : ∆t passing through H2O

→ Thinner cell & focused EB

OK

Note: O.D. = ε C l l↓ for better time resolution, but O.D.↓then, C↑ for O.D.→

H2O(5mm)EB

>40Gy/pulse13-15GyDose2ps3psPulse width

3mm4mmBeam size1.7-2.0nC0.8-1.0nCChargeCurrentPrevious

Estimation of dose by RadColor

Introduction of white light continuum- 795nm → white- Worse stability of intensity- S/N↓ then average↑

CurrentPrevious400-1100nm795nmWavelength

6416Average~0.015 OD~0.005 ODNoise

- Accumulation 2000pulses- Red region corresponds to 80-100kGy

Improvement

-0.050.000.050.100.150.200.250.300.35

0 50 100 150 200 250Time /ps

Optical path : 10 mm

5 mm

2 mm1 mm

-0.050.000.050.100.150.200.250.300.35

-10 -5 0 5 10 15 20 25 30Time /ps

12-13ps

6-7ps

4-5ps

<4ps

• Time behaviors of eaq- at 700nm

Results

Time resolution: δtotalδtotal = δdiff + (δE

2 + δL2 + δsync

2 )1/2

Dominant factor： δdiffdue to refractive index n=1.33

Radiolysis of water measured at 700nm www.utnl.jp/~beamBeam-Material Interactions

50Gy50Gy47Gy40GyDose

<4ps4-5ps6-7ps12-13psTime resol. /ps

0.043

0.085

0.1910

0.3215

O.D.S/N

12510l /mm

12.2ps 3.2ps5.2ps7.2psTime resol. /ps

Good agreement

SPR KPR Dose Scav. Sim. G(time) 1970 Tront --- Kinetics only 1973 Tront ● ● 4.0(30ps)

● ● 4.0(30ps) 1973 ANL ● ● 4.1(200ps) Sub-ns KPR 1975 Tront ● ●

● ● 4.6(dry) Dry electron 1976 ANL ● ●

(1973) 4.6(100ps)

4.1(1ns) Reconcilation

1973 1985 Hokkaido ● ● 4.8(30ps) 1985

- 1996

● ●

1996 NDRL & ANL

● ● 4.8(100ps) Reconciliation 1976

1999 ANL ● ● 4.0 (time zero)

Fs laser Reconciliation

2000 Tokyo ● ● ●

G [molecules/100eV]www.utnl.jp/~beam

Beam-Material InteractionsG-value of the solvated electron

nH2O

H2O+ + e-

H2O* → H2O+ + e-

- Initial G： 4.0~4.8- Primary G: 2.7

Reported G(eaq-)

Which G is reliable ?

epre- → eaq

-

eaq- , H3O+, H, OH, H2, H2O2

＜1ps

~100ns

0

1

2

3

4

5

6

10-12 10-11 10-10 10-9 10-8 10-7 10-6

Time /s

G=4.1

G=2.7G=2.38

Monte-Carlo simulation [1]

www.utnl.jp/~beamBeam-Material InteractionsApplication of RF-Gun Pulse Radiolysis

• G(eaq-) measured at 795 & 633nm

• Ps by SPR (795nm)• Ns by KPR(He-Ne laser) (633nm)

Condition

G(20ps)=4.17±0.22

Time resolution

Note1 : O.D. already normalized by chargeNote2 : O.D. at 633nm normalized by ε

ε : 15500(633nm), 16800 (795nm)

Stroboscopic method Kinetic method

ArGas

64Average

0.8-1.0nC4mm3ps

ChargeBeam sizePulse width

18 mml / mm

H2OSample

[1] Y. Muroya, J.-P. Jay-Gerin, Y. Katsumura et al,Can. J. Chem., 80 (2002) 1367

www.utnl.jp/~beamBeam-Material InteractionsG of solvated electron in alcohols

21.514.1[1]11[7]7.8[2][1]51

14000(650nm)[7]2.01-decanol

3.18.95[1]7.36[7]10.3[2][1]451.41-octanol

3.82.56[7]17.1[2][1][2]

3039[6]

12000(635nm)[7]

1.92.3

1-butanol

6.52.04[7]18.3[2]

[1][3][2][5]

258400(575nm)

14000(?)13000(820nm)[7]

2.31.52.8,1.81.0

2-propanol

81.92[7]20.1[2]

[3][4][2][5]

24[1]34[6]

8400(575nm)12800(700nm)

13000(?)11000(640nm)[7]

1.82.02.9,2.31.0

1-propanol

10.21.07[7]24.3[2]

[1][3][4][2][5]

1823[6]12000(575nm)

9300(700nm)

15000(?)9900(690nm)[7]

2.71.63.42.81.0

Ethanol

14.80.55[7]32.6[2]

[1][3][4][2][5]

1110.7[6]15500(575nm)

10200(630nm)

17000(?)10400(630nm)[7]

2.51.63.43.1,3.01.1

Methanolρ/1021cm-3[1]η/cPDRef.τsε /M-1cm-1G

7500(570nm)[7]Propylene Glycol(1.04)(1,2-PrD)

6000(575nm)[7]1,3-Propanediol(1.05)

9700(530nm)[7]Glycerol(1.26)(1,2,3-PrTri)

19.9[1]37.7[4][5]

<5[1]26

14000(580nm)14000(?)

2.31.2

Ethylene Glycol

ρ/1021cm-3[1]η/cPDRef.τsε /M-1cm-1G

www.utnl.jp/~beamBeam-Material InteractionsG of solvated electron in alcohols

[1]G.A.Kenny-Wallace, C.D.Jonah, J.Phys.Chem., 86 (1982) 2572[2]R.R.Hentz, G.A.Kenny-Wallace, J.Phys.Chem., 78 (1974) 514[3]W.K.Wolff, J.W.Hunt, J.Phys.Chem., 77 (1973) 1350[4]T.Sumiyoshi, M.Katayama, Bull.Chem.Soc.Jpn., 58 (1985) 3073

[5]M.J.Bronskill, J.W.Hunt, J.Chem.Phys., 53 (1970) 4201[6]W.J.Chase, J.W.Hunt, J.Phys.Chem., 79 (1975) 2835[7]C.Ferrandini, J.-P.Jay-Gerin, CRC press, (1991) 259

www.utnl.jp/~beamBeam-Material InteractionsG of solvated electron in alcohols

G(MeOH) = 4.1 @50psG(EtOH) = 3.6 @50ps

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

-20 0 20 40 60 80 100 120Time /ps

Methanol

Ethanol

600nm

1100nm

700nm

1100nm

Ethanol700nm1100nm

600nm1100nm

Wavelength

64Average10 mml / mm

MethanolSample

Dose : 37Gy

• Initial G(esol-) measured at VIS&IR

Condition

Procedure of G-value determination(1) H2O measurement at 700nm(2) Dose calculation(3) Alcohols measurement at λmax

www.utnl.jp/~beamBeam-Material InteractionsResults and discussion

ε is correct?

Shorter τLarger dielectric constant→ large G

fs laser reported-esol

- doesn’t recover ~10%

esol-(MeOH) > esol

-(EtOH) ~ eaq-

Necessity to measure whole time region from ps to µs

366006.16000(600nm)

1,3-Propanediol(1.05)

330004.08250

(600nm)Glycerol(1.26)(1,2,3-PrTri)

330004.47500(570nm)

Propylene Glycol(1.04)(1,2-PrD)

768004.218300(700nm)

H2O(1.00)

392002.814000(600nm)

EG(1.1)

337502.513500(600nm)

1-decanol(0.84)

290002.511500(700nm)

1-butanol(0.81)

276002.312000(700nm)

2-propanol(0.79)

343002.712700(700nm)

1-propanol(0.80)

356403.69900

(700nm)Ethanol(0.79)

410004.110000(600nm)

Methanol(0.79)

Initial GεInitial Gε /M-1cm-1Solvent (ρ /cm3)

??

0.000

0.050

0.100

0.150

0.200

0 50 100 150 200 250

700nm1100nm

Time /ps

1-PrOH

www.utnl.jp/~beamBeam-Material InteractionsResults and discussion

Report

This work18077502813τ (ps)@1100nm5130241810τs (ps)

32

9PrOH

10BuOH

15119τ (ps)@700nm or 600nm

2210τ (ps)@1300nm

DeOHEtOHMeOH

• Formation time is faster than previous reports• Decay appreciates with previous reports

-0.20

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-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

-20 0 20 40 60 80 100 120Time /ps

Methanol

Ethanol

600nm

1100nm

700nm

1100nm

www.utnl.jp/~beamBeam-Material InteractionsRadiolysis of water : spectrum

0.000.050.100.150.200.250.300.35

400 500 600 700 800 900 1000 1100

ReportedH2O5M NaOH

Wavelength /nm

64Average400 – 1100 nmWavelength

10 mml / mmH2O & 5M NaOH

• G(eaq-) measured from VIS to IR

Condition

<700nm : O.D.(alkali) > O.D.(neat)>700nm : O.D.(alkali) < O.D.(neat)

20% absorption increase7% density increase Increase of G

www.utnl.jp/~beamBeam-Material InteractionsSummary

• Development of new pulse radiolysis system combined withlaser photocathode rf-gun and fs white light continuumhas been almost completed.

• <4ps time resolution was achieved.

• It has been started application of the system to clarifyradiation-induced fast processes, i.e., G-value of eaq

- ,esol

- from several kinds of alcohol.