Analysis results for PPO samples irradiated 7/13/2001 at MITR
Zelimir Djurcic and Andreas Piepke1
University of Alabama
(Status 8/2/2001)
(Updated 9/6/2001)
We present the analysis results for different KamLAND PPO samples. All of the batches analyzed are
actually used in KamLAND. All samples were subjected to the standard post irradiation procedures,
outlined in a separate document. The table below lists
the activities measured for the
acid collected after ion exchange.
All measurements were performed with
the "old Ge detector". The counting systematics should hence largely cancel when comparing different
samples with each other. Activities are reported for a delay of 84 hours
since end of irradiation. The errors reported are the quadratic sum of the statistical and a 10%
systematic error.
Results
The following table lists the element concentrations determined for KamLAND PPO.
For Na, Br and Au the acid digestion efficiency is known. For
the other elements not. In the following table we assume an efficiency of 100% for all elements.
This approximation does not influence the sample comparison in which the efficiency cancels.
To arrive at the real chemical concentration divide by the digestion efficiency given below for
Na, Br and Au.
Values given in red
were determined for the PPO those in blue are the appropriate blanks.
"Packard mix" (UA47) denotes the original PPO as shipped from Packard in Holland to UA. This sample defines
the "bottom line". An empty irradiation vial (UA46) was exposed to the same cleaning and filling
procedures to determine the blank, listed in the table. This empty vial was activated along with
the other samples. "Unpurified PPO" (CIT54) is a sample of PPO which had been dissolved at high concentration
in pseudocumene (PC) in Sendai. The sample has been taken on 4/27/2001. At Caltech the solution
was dried in a clean vacuum oven. The left over PPO was then activated. A sample of PC-dissolved PPO,
taken after water extraction (UA53) on 5/7/2001, was solidified in parallel with the unpurified PPO. An empty
irradiation vial (UA55) was placed inside the oven too. This vial, which was activated as well, serves to determine
the blank and allows to exclude sample migration between the vials during evaporation.
| Sample |
Na
[µg/g] |
Cr
[ng/g] |
Co
[ng/g] |
Zn
[ng/g] |
Br
[ng/g] |
Au
[pg/g] |
| Packard PPO mix
| 1.4±0.2
-
| 16±2
1.6±0.2
| 2±0.2
5.5±0.6
| 62±6
33±3
| 17±2
5±5
| 0.7±0.4
-
|
Unpurified
evaporated PC-PPO
| 0.1±0.01
0.073±0.008
| 4.8±0.7
1.5±0.2
| 3.1±0.3
-
| 258±26
200±20
| 8.3±0.8
0.3±0.05
| 7.7±0.8
4.3±0.5
|
Purified
evaporated PC-PPO
| 0.13±0.02
0.073±0.008
| 5.2±0.5
1.5±0.2
| -
-
| 52±5
200±20
| 7.2±0.7
0.3±0.05
| 4.8±0.5
4.3±0.5
|
Interpretation of these data
An obvious reduction in the concentration of the listed chemical impurities is observed between the original
PPO delivered from Packard and the dissolved-evaporated PPO. The reduction factors observed for Na, Cr and Br
vary between 2 to 10. Co, Zn and Au have substantial blanks which make a reliable determination of reduction
factors impossible. However, an improvement in chemical purity is not observed when comparing the purified and unpurified
PPO samples. Br exhibits this the best because the blank is negligible (in all activations done in the past Br gave always
the most stable and predictable results). This observation perhaps suggests that the Br is present in
form of an organic compound which is insoluble in water. The ionic Na is only slightly above blank for both
evaporated PPO samples. The purification factor might hence be masked by a blank fluctuation.
Remarks
Upon receipt 7/17/2001 10:17 it was noted that the irradiation vial
of sample UA53 was cracked. To not have any of the
acid used in the external cleaning contaminate the sample it was cleaned by hand dipping it partially
into the acid bath leaving the crack out of the liquid. UA53 therefore underwent
a non-standard cleaning procedure which might result in external contamination interfering with the
sample counting.
Sample UA46 was subjected to the standard cleaning procedure. It was then found that the irradiation vial
had a small crack too leaving the possibility that some of the external cleaning acid did migrate into
the interior of the vial.
Although not listed here an invisible crack was also identified in the vial containing the flux standard
UA56. This crack could only be identified by the fact that the acid used for the cleaning was contaminated.
As we received 9 irradiated samples this time we decided to process two samples in parallel. This was
necessary to get early counting data for all important samples. After processing of a sample pair the
fume hood was cleaned and all instruments except the hot plate replaced. Only new glass
ware was used in all cases.
The following samples were processed together:
7/17/2001 17:25 - 7/18/2001 1:10: UA45 sample of Packard PPO 21-634 and UA47 mix of all Packard batches
used in KamLAND.
7/18/2001 14:00 - 17:45: UA46 UA sample preparation blank, an empty vial. UA55 the Caltech evaporation
blank, also an empty vial.
7/18/2001 18:50 - 8/18/2001 1:40: UA53 PPO dissolved in PC, collected in Kamioka (5/2/2001)
after water extraction and then evaporated at Caltech.
CIT54: same material but collected before water extraction (4/27).
7/20/2001 15:08 - 19:00: UA54 the Caltech bottle blank.
No spiked sample has been processed at all.
Detailed Analysis Results
All activities and concentrations listed were evaluated assuming 100% acid extraction efficiency. For
Na, Br and Au the extraction efficiency could be estimated by determining the activities contained
in all materials and componets used in the post irradiation preparation. This has been done for
7 different samples. We find the following fraction of the total activity in the acid collected after
ion exchange and its standard deviation:
24Na: Mean 0.84, Sigma 0.07
82Br: Mean 0.48, Sigma 0.06
198Au: Mean 0.18, Sigma 0.03
By this we conclude that our chemical sample preparation is consistent within ±10%.
| |
UA45 Packard 21-634
ti=1 h, m=1.2638 g |
UA47 Packard UA mix
ti=11 h, m=0.9756 g |
UA46 UA preparation blank
ti=11 h, m=0 g use 0.9756 g |
CIT54 CIT evapor.
PPO
before water extraction
ti=1 h, m=0.869 g |
UA53 CIT evapor. PPO
after water extr.
ti=11 h, m=0.8634 g |
UA55 CIT evapor. blank
ti=11 h, m=0 g use 0.8634 g |
UA54 CIT bottle blank
ti=11 h, m=0 g use 0.8634 g |
|
| |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
|
| Na |
1513±151 |
(2.7±0.27)·10-6 |
5400±540 |
(1.4±0.14)·10-6 |
|
|
40±5 |
(105±13)·10-9 |
419±42 |
(125±13)·10-9 |
245±27 |
(73±8)·10-9 |
162±25 |
(49±7.5)·10-9 |
Na |
| K |
(-66±26) |
(-2.0±0.8)·10-6 |
-68±58 |
(-318±271)·10-9 |
|
|
(-24±14) |
(-1064±620)·10-9 |
13±15 |
(69±79)·10-9 |
38±25 |
(201±132)·10-9 |
359±214 |
(1.9±1.1)·10-6 |
K |
| Sc |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Cr |
(0.74±0.12) |
(2.2±0.36)·10-9 |
46±4.6 |
(16.4±1.6)·10-9 |
4.4±0.6 |
(1.6±0.21)·10-9 |
1.1±0.15 |
(4.8±0.66)·10-9 |
13±1.3 |
(5.2±0.5)·10-9 |
3.6±0.5 |
(1.5±0.2)·10-9 |
1.2±0.16 |
(0.48±0.065)·10-9 |
Cr |
| Fe |
-0.027±0.012 |
(-28.5±12.7)·10-9 |
0.04±0.06 |
(5.0±7.5)·10-9 |
-0.11±0.054 |
(-13.7±6.7)·10-9 |
-0.036±0.013 |
(-55±20)·10-9 |
0.034±0.063 |
(4.8±8.9)·10-9 |
0.051±0.079 |
(7.2±11.2)·10-9 |
-0.036±0.013 |
(-5.1±1.8)·10-9 |
Fe |
| Co |
2.4±0.24 |
(2.8±0.28)·10-9 |
14.2±1.4 |
(2.0±0.2)·10-9 |
40±4 |
(5.5±0.55)·10-9 |
1.8±0.2 |
(3.1±0.31)·10-9 |
78(?) |
|
68±7 |
|
0.25±0.03 |
(39±4)·10-12 |
Co |
| Zn |
1.1±0.12 |
(60.9±6.6)·10-9 |
9.5±1.0 |
(62.0±6.2)·10-9 |
5.0±0.5 |
(32.6±3.3)·10-9 |
3.2±0.33 |
(258±26)·10-9 |
7.0±0.7 |
(51.6±5.2)·10-9 |
27±2.7 |
(199±20)·10-9 |
9.6±1 |
(71±7.2)·10-9 |
Zn |
| Br |
30±0.3 |
(12.2±1.2)·10-9 |
320±32 |
(16.9±1.7)·10-9 |
95±97 |
(5.0±5.1)·10-9 |
14±1.4 |
(8.3±0.84)·10-9 |
121±12 |
(7.2±0.72)·10-9 |
4.8±0.8 |
(0.29±0.05)·10-9 |
5.1±0.7 |
(0.31±0.04)·10-9 |
Br |
| Sb |
0.5±0.35 |
|
6.7±0.8 |
|
15±4.5 |
|
1.5±0.2 |
|
7.5±0.8 |
|
2.5±0.35 |
|
1.4±0.2 |
|
Sb |
| Hf |
-0.023±0.013 |
|
-0.015±0.052 |
|
0.034±0.058 |
|
-0.002±0.014 |
|
0.083±0.051 |
|
-0.054±0.054 |
|
-0.029±0.027 |
|
Hf |
| Au |
0.24±0.60 |
(2.9±7.4)·10-12 |
0.45±0.22 |
(0.69±0.34)·10-12 |
|
|
0.43±0.07 |
(7.7±0.7)·10-12 |
2.8±0.3 |
(4.8±0.5)·10-12 |
2.5±0.3 |
(4.3±0.52)·10-12 |
2.1±0.25 |
(3.6±0.43)·10-12 |
Au |
| |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
Activity [Bq] |
Conc. [g/g] |
|
| |
UA45 Packard 21-634
ti=1 h, m=1.2638 g |
UA47 Packard UA mix
ti=11 h, m=0.9756 g |
UA46 UA preparation blank
ti=11 h, m=0 g use 0.9756 g |
CIT54 CIT evapor.
PPO
before water extraction
ti=1 h, m=0.869 g |
UA53 CIT evapor. PPO
after water extr.
ti=11 h, m=0.8634 g |
UA55 CIT evapor. blank
ti=11 h, m=0 g use 0.8634 g |
UA54 CIT bottle blank
ti=11 h, m=0 g use 0.8634 g |
|
This page is maintained by A. Piepke
Last update September 6, 2001