DS-Mat regular meeting

Tuesday 3 Dec 2019, 17:00 → 18:00 Europe/Rome

Assistents:
Santorelli, Gromov, Chepurnov, Jillings, Bottino, Pelczar, Mroz, Pesudo, Agnes

 

Cross calibration:

The three reference samples have been combined into one at SNOLAB. This one has been divided into three identical ones. One will stay at SNOLAB, one will go to Canfranc and one to LNGS (They expect to have them picked up this week). The info on the sample and the mixing will be sent to Vicente.

 

With respect to the see bottom sediment a potting technique that works has been identified. So they are ready to order the proper sample.

 

Cosmogenic:

Susana reported via mail that the first steps towards a paper on activation are being made. Roberto stresses the need of a agreeing on a paper that includes Ar transport and storing contribution. We need to coordinate with Urania and it might be interesting to interact with them during their meeting next week.

 

Gadolinium:

Alex explains with a bit more details the samples produced in Russia. This purity is obtained as a by-product of getting 5N quality material. For this certification, the level of 65 impurities needs to be reduced so that the purity is above 99.999%. None of those impurities is U or Th, but the result helps in that direction too.

He states that The Gd(NO3)3, which is the purest, could be used to produce Gd2O3, but probably not in nanograins and testing of the mixing would be necessary. The Gd2O3 produced has a lower n-yield than the best one from SuperK, but mixing needs to be tested too.

 

Reporting from Integration meeting:

The importance of the cryostat, its radiopurity and its composition was evidenced and understood by the relevant people.

Some relevant RPUF information clarified (90 kg/m3 foam only).

Some more info delivered via mail right after and the interaction with them has been reactivated.

The possibility of a PE layer (or similar) in the inner layer of the cryostat is mentioned and will be evaluated in more detail.

 

Assay reports:

Assays going on in Krakow, LNGS, Boulby and Canfranc. Krakow reports on the OPA356 chips having 22 Bq/kg in 210Po.

 

AOB:

Chris mentions it would be a good idea to invite Mark to talk on the surface contamination studies reported in Napule. Paolo comments that several of the assumptions there are very conservatives.

We agree in identifying a day for this meeting, probably out of the usual Tuesday DS-Mat slot.

 

 

Follow up items:

Gd: agreement between Russia, China, EU to circulate samples.

Gd: evaluate the neutron yield of the naturally occurring alpha-emitting nuclei identify in the excel that Alex sent around.

Gd: Make a clear statement of this purity being enough.

Surface: dentifying a day for a meeting with Mark Boulay.

 

17:00 → 17:10 Plans on cosmogenics

Speaker: SUSANA CEBRIAN (UNIVERSITY OF ZARAGOZA)

We can start to prepare a first draft for an article summarizing the calculations on cosmogenic activation of copper, steel and argon and its effect for DarkSide. Final numbers for argon can be tuned according to a more realistic schedule for the transportation and storage from Urania, to Aria and to Gran Sasso. On 11 December there is a face-to-face meeting in Cortez (https://agenda.infn.it/event/21007/ ); we can wait for their conclusions.
- Two samples are being screened now in Canfranc: resistors HVCB1206, showing an excess over background, and PCB from motherboards. Last results from Gd oxide from IOLITEC are already available at the database.

17:10 → 17:25 Plans for Gd in Russia

17:25 → 17:35 feedback from integration meeting (cryostat)

17:35 → 17:50 Assay requests and reports

17:50 → 18:00 AOB