Packard Batch 21-634 Sample Preparation

(Done: 3/14/2001)

A total of 35 large plastic irradiation vials (screw cap type) were prepared for neutron activation at the MIT research reactor. Samples of Packard PPO (batch 21-634), empty vials (which were subjected to the same treatment) and spiked samples were included.
The spiked samples were prepared at Caltech and only packed into secondary containment bags at UA. All other vials were prepared in UA's cleanromm facility. Prior to filling all vials were double cleaned with high purity HNO₃ (U/Th < 10^-10 g/g) and in a second step with ultra-high purity HNO₃ (U/Th < 10^-13 g/g), followed by a rinsing with double de-ionized water. The vials were then dryed in a clean room oven. 18 of the vials were filled with Packard PPO, batch 21-634. About 1.0 to 1.2 g of PPO was filled into each vial, leaving about 60% expansion space in the vial. The vials were then melted shut using a soldering iron (which remains in the cleanroom and is only used for this purpose). Every vial was heat sealed into a secondary containment plastic pouch to contain possible spills. The following table lists all samples prepared for the March 2001 neutron beam time at MIT. Samples displayed in red are blanks, samples shown in blue PPO, and those listed in green are spiked.
UA counting results are referenced to 3/24/2001 10:28 (CST). The rightmost column lists the appropriate shipping delay in hours.

		Mass [g]			Irradiation (CST)
Sample	Rabbit	Empty	Full	Soldered	Begin	End	Delay [h]
CIT 9		2.5917		2.5893
CIT 14		2.6189		2.6151
CIT 15		2.5867		2.6027
CIT 16		2.6350		2.6312
CIT 17		2.6023		2.5975
CIT 18		2.6131		2.6094
UA 9	A	2.6234		2.6234	3/21/2001 17:26	3/21/2001 22:26	60.0336
UA 10	A	2.6405		2.6372	3/21/2001 17:26	3/21/2001 22:26	60.0336
UA 11	A	2.6296		2.6197	3/21/2001 17:26	3/21/2001 22:26	60.0336
UA 12	B	2.6031		2.6003	3/21/2001 22:29	3/22/2001 3:29	54.9840
UA 14	C	2.6237		2.6123	3/22/2001 3:29	3/22/2001 8:39	49.8168
UA 15	D	2.6367		2.6320	3/22/2001 8:47	3/22/2001 13:47	44.6832
CIT 19		2.6506	3.8555	3.8514
CIT 20		2.5842	3.8424	3.8385
CIT 21		2.6301	3.6581	3.6463
CIT 22		2.6006	3.6420	3.6405
CIT 23		2.6393	3.7727	3.7707
CIT 24		2.5979	3.7202	3.7194
CIT 25		2.6194	3.7144	3.7085
CIT 26		2.6034	3.7248	3.7203
CIT 27		2.6337	3.7080	3.7057
UA 19	B	2.6097	3.7866	3.7816	3/21/2001 22:29	3/22/2001 3:29	54.9840
UA 20	B	2.5990	3.7375	3.7333	3/21/2001 22:29	3/22/2001 3:29	54.9840
UA 21	B	2.6217	3.8017	3.7964	3/21/2001 22:29	3/22/2001 3:29	54.9840
UA 22	C	2.6243	3.8390	3.8355	3/22/2001 3:39	3/22/2001 8:39	49.8168
UA 23	C	2.6285	3.7379	3.7314	3/22/2001 3:39	3/22/2001 8:39	49.8168
UA 24	C	2.6210	3.7272	3.7234	3/22/2001 3:39	3/22/2001 8:39	49.8168
UA 25	D	2.6291	3.7451	3.7436	3/22/2001 8:47	3/22/2001 13:47	44.6832
UA 26	D	2.6027	3.6886	3.6859	3/22/2001 8:47	3/22/2001 13:47	44.6832
UA 27	D	2.6016	3.7387	3.7355	3/22/2001 8:47	3/22/2001 13:47	44.6832
CIT 28 Na,K,Br,Th,U
CIT 30 PPO: Th,U
UA 28 Na,K,Br,Th,U	A				3/21/2001 17:26	3/21/2001 22:26	60.0336
UA 30 PPO: Th,U	A				3/21/2001 17:26	3/21/2001 22:26	60.0336

In samples UA 26 and UA 27, contained in rabbit D, leaked PPO during irradiation. Although the molten PPO was contained in the poly-bags these samples were not used in our analysis.