1

Update of US Gd-LS

Minfang Yeh and Richard L. HahnBNL, Chemistry Department,

Upton NY

2

430 nm

Optical of ~1% Gd in LAB and in PC

Few percents of Gd can be loaded into pure LAB or pure PC, respectively, using BNL carboxylate recipe.

Both LS needs additional organic solvent: Gd-LAB needs diluent (PC) to dissolve certain

shifters. Gd-PC needs inert diluent (MO or dodecane) to

improve compatibility.

3

0.000

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

0.010

0.011

0.012

0.013

10/15/04 12/14/04 02/12/05 04/13/05 06/12/05 08/11/05 10/10/05 12/09/05 02/07/06 04/08/06 06/07/06

Calendar Date

abs l

at 43

0 nm

1.2% Gd in PC 0.2% Gd in PC0.2% Gd in 20%PC 80% Dodecane0.2% Gd in LAB0.2% Gd in 20%PC 80%LAB

566 days

514 days

426 days

189 days

May 08, 2006

189 days

Stability of Gd-LS in PC (10 cm cells)

4

BNL Proposed Gd-LS (1) Gd in LS Gd-Carboxylate

Liquid Scintillator

PC + dodecane

Loading Methods

Solvent-solvent Extraction

[Gd] 1 g/L

Density ~0.79 g/mL

> 15m

Stability > 1.5 years

Future Study

Mature and ready for

prototype study; Compatibility

Test

0.2%Gd in 20%PC 80% dodecane

0

0.005

0.01

0.015

0.02

350 400 450 500 550 600 650 700l(nm)

Abs

AttLl

12 L of 0.2%Gd in 20%PC + 80%dodecane situated at the University of Chicago for prototype

5

Light Yield as a Function of PC% in dodecane

0.00

0.20

0.40

0.60

0.80

1.00

0 10 20 30 40 50 60 70 80 90 100

PC %

S%

No

rma

lize

d

6

BNL Proposed Gd-LS (2)Gd in LS Gd-Carboxylate

Liquid Scintillator

PC + LAB

Loading Methods

Solvent-Solvent Extraction

[Gd] 1 g/L

Density ~0.87 g/mL

> 15m

Stability > 6 months

Future Study

Compatibility Test

QC monitoring

0.2% Gd in 20%PC 80%LAB

0

0.005

0.01

0.015

0.02

350 400 450 500 550 600 650 700l (nm)

Abs

AttLl

Light yield is ~100% of PC

7

Buffer/Shielding

Mineral Oil(C24~C28)

LAB(C11~C13)

Water

Cost

Flash Point

215oC 130oC -

PurityNot

consistentControlled production

Easy to purify

Availability

Density 0.85 g/mL 0.86 g/mL 1 g/mL

8

Buoyant Force

f

f

objectfluid

objectfluid

shieldingbufferLSunloadedLSGd or ::

http://www.ac.wwu.edu/~vawter/PhysicsNet/QTMovies/PressureFluids/

9

Selection of Fluors

Wavelength Shifter (shift the UV light to the visible region)

Primary Secondary

Concentration (1.5 ~ 6 g/L)

td (ns)Concentration

(15 ~300 mg/L)

td (ns)

butyl-PBD 1.1bis-MSB 1.6

PPO 1.5

p-TP 0.95POPOP 1.5

PBD 1.1

10

1

10

100

1000

500 700 900 1100 1300 1500 1700

Channel

Coun

ts

PBD 3g/L

PBD 3g/L MSB 15mg/L

butyl-PBD 3g/L

butyl-PBD 3g/L MSB 15mg/L

1

10

100

1000

500 1000 1500 2000 2500 3000

Channel

Coun

ts

butyl-PBD 3g/L

butyl-PBD 3g/L MSB 15mg/Lbutyl-PBD 30g/L

butyl-PBD 30g/L MSB150 mg/L

Q1: Adding bis-MSB in butyl-PBD doesn’t improve the light yield much; on the other hand, additional bis-MSB in PBD increases the light yield by a factor of ~2.

Q2: What are the quantities of shifters that we need?

Example of PBD vs butyl-PBD

11

0.00

0.20

0.40

0.60

0.80

1.00

0 5 10 15 20 25 30 35 40

Flours (g/L)

S%

no

rma

lize

d

Light Yield as a Function of Fluors (butyl-PBD:bis-MSB=200:1)

12

Blending of Conc. Gd-LS Immiscibility of solvents. Localization of Gd compound can

cause irreversible precipitation Controlled Mixing:

Fast and vigorous (not suitable for massive quantity)

Slow and gentle, i.e., Gd-PC/MO at ~3L/min (Palo Verde at 200 L per batch)

Commercially available 100-L (capable of upgrade to 300-L) Jacketed System with air or electric pump

13

Port of Houston

photos adapted from NOvA

20ft by 8ft ISO tank, the shipping container conforming to the standards set by International Standards Organization, can be leased at ~few $thousands per year.

The tank shell is made of stainless steel and holds 6,341 gallons of liquid.

Transportation and Storage of LS

14

Gd/H and C/H Ratios

Cold/Thermal Neutron AnalysisInstitute of Isotopes, Dept. of Nuclear ResearchHungary Academy of Science, Budapest, Hungary

Samples sent out on May 20, 20061. 0.1% Gd in 90% LAB and 10% PC2. 0.1% Gd in 80% dodecane and 20% PC3. 80% dodecane and 20% PC4. 100% LAB

Samples received on June 04, 2006; will be analyzed next week.

Nuclear Magnetic Resonance

Brookhaven National Laboratory, Chemistry Dept.A FaST team (Dr. S. Seleem and her students) will work with us at BNL beginning on June 26.

15

Summary and Future Work Samples of 0.1~0.2% of Gd in a variety of liquid scintillators

and their mixtures are continuously monitoring : 546 days for 0.2%Gd in 100%PC 416 days for 0.2%Gd in 20%PC-80%dodecane 456 days for 0.2%Gd in 40%PC-60%dodecane 189 days for 0.2% Gd in 100%LAB 189 days for 0.2% Gd in 20%PC - 80%LAB

The productivity of Gd-LS at 1-L of 1%Gd-LS (~ 10L of 0.1%Gd-LS) per preparation is consistent; exploring the techniques and equipments for even larger quantity (10L of 1% Gd-LS) production.

Fluorescence for fluors in different combinations of liquid scintillators need to be studied further.

People Compatibility test of acrylic vs. organic solvent. Chemical assays to remove and to measure U/Th. Prototype in Aberdeen Tunnel HK