Stereo Collab Meeting | CEA Saclay July-2015 STEREO COLLAB. MEETING CEA Saclay 1-3 July 2015 ©La...

Stereo Collab Meeting | CEA Saclay July-2015

STEREO COLLAB. MEETINGCEA Saclay 1-3 July 2015

©La Recherche – Oct. 2014

1


PLANNING

Pivot of the experiment: we are entering the fabrication phase after accumulating numerous constrains on the design to fulfill safety requirements and to mitigate external backgrounds.

The planning has drifted it is now very tight to get two cycles of data for physics in 2016.

We must meet the current milestones to stay competitive. We can do it.

2

Det.@ILL

Cycle 1

March 2016

April 2016

Detector filled

June 2016

Cycle 2 Cycle 3

Validate bkg


PLANNING

The critical path so far is the installation of the inner detector at ILL.

Goal: delivery of the stainless steel vessel at LPSC mid-feb 2016 transport to ILL end of March 2016, before the reactor restarts.

Tender process almost finished. Irfu team mobilized to keep costs and planning within expectations (see Caroline’s talk).

Need to confirm that the planning of the lead and polyethylene shielding around Stereo fits the above milestones. Pending issue of tender process for the lead.

3


SHIELDING SUPPORT STRUCTURE - LAPP

Stereo shielding Structure: • Borated polyethylene• Lead• m Veto

Fixed to the ground by welding on plates

Transport plate underneath the structure. 10 air cushions with 120 t lifting capacity.

93 t total mass

4


REPLACEMENT OF THE H7 TUBE

5

• The H7 tube reaches its limit dose end of 2016. This would require the Stereo experiment to stop its work on site from Jan to March 2016.

• Option 1: the tube is produced and the installation process (welding) is validated by the end of 2015 replacement in winter 2015/16.

• Option 2: the tube is not ready end of 2015 replacement in winter 2016/17. Requires to unfill – remove the experiment.

• Option 3: the tube is removed and its volume is filled with water design of a new end cap for our beam stop (?)

Ste

reo


PREPARATION OF THE ILL SITE

Next Steps – 2015

Ste

reo

B4CPlomb

Front wall lead (MPIK) – to be installed this summer

Side lead shielding along D19 and IN20 – design in progress at ILL.

Anchor points and floor surface (ILL) – Next winter stop

6

• Lead shielding designed to suppress the current gamma flux with some margin.

• Extra margin given by neutron absorbers in front wall, D19 and IN20.

• High background sensitive to holes in the protection.

See S. Fuard’s talk


SECURITY FILE

7

Seismic studies• On track• All subsystems validated by a certified

company, NECS.• Final calculation note being written

Fire studies• Critical item for the safety file• End of consultation with 3 companies (Nuvia,

Kaefer-Wanner, Elit).• Two months work for the “avis de chantier”,

used as argumentation for the ASN file. Submission of the safety file this autumn for

filling authorization in ~April 2016.

Mode #1 @11.4Hz

See S. Fuard’s talk


LEAD FOR FREE

8

Old treasure of 85 t of clean lead.

Buried since the 50’s in a casemate of CEA Saclay and being dug up.

Obtained 55 t for Stereo.

Work in progress on site since Monday, 7t /day.

Transportation to ILL-Grenoble foreseen to be completed before end of this month.

Cost covered by the “endurance” program of ILL. ILL becomes owner of this lead to be used on a neutron line by late 2018.

Irfu covered the expenses for the remaining 30 t, transferred to the Orme site.


LEAD FOR FREE

9

CERN

Official approval from CERN direction (S. Bertolucci) for 80t of lead instead of the initial 60 t.

Draft of CERN-IN2P3 agreement for transfer to LAPP-Annecy.

Direct transport to the foundry.

Need to organize the sharing of this lead after the experiment (Stereo MOU).

Total of 135 t of lead to be recovered for the experiment !

Adding the 10 t lent by LPSC this covers the need of Stereo


MAGNETIC SHIELDING

10

• Stray field from a magnet of the IN20 casemate requires a hermetic magnetic shielding around the experiment.

• Two complementary simulations show that we need a double layer protection: soft iron around the lead shielding (used to hold the fire protection), mu-metal box around the detector.

• Significant overcost but covered by the extra recovery of lead from CERN and Saclay

• Design being finalized at LAPP and ILL.

Simulations: ILL & LPC Caen. Mu-metal assembly


PROTOTYPES TESTED

11

Several prototypes validated allowing the fabrication of the final item:

m-veto Liquid scintillator samples Detector cell Front-End electronics

PMTs delivered, to be tested

PMT base – under test Calibration system – under test &

development


CONCURRENT EXPERIMENTS

All schedules foresee data taking by ~mid 2016

Neutrino4

DANSS

Solid – 288 kg module

Korean project – long baseline

CeSox – source in Gran Sasso before end of 2016

Nucifer – sensitivity limited by accidental background

12


COSMIC RAYS INDUCED BACKGROUND

13

m rate (Hz)

Cor

rela

ted

pair

s /

day

Nucifer observation:

The muon rate is not constant close to surface. Few % variation in the flux of saturating muons are observed, correlated with Patm

The correlated background is quite sensitive to these variations.

Simple reactor OFF subtraction is not sufficient. Need a reliable monitoring of the muon flux, good and stable PSD.

Simulation of muon induced background to understand better the relation between the saturating muons and the correlated background?


SAFETY FILE

14


Aligned with the water channel:

L0=10.0 m

Angle / core direction =18.7° Effective det. length 2.25 m 2.10

2nd position 1.4 m backward can extend the baseline coverage and provide a powerful crosscheck of systematics.

Option for the second part of data taking after Jan 2017.

CONFIGURATION

15


SENSIBILITY

300 days, ~480 ne/day

L0 = 10.0 m

Eprompt>2 MeV Edelayed>5 MeV

dEscale = 2%

All syst. of predicted spectra

S/B = 1.5, 1/E + flat

Norm:- 3.7% absolute norm.- 1.7% relative norm. between cells

16


PLANNING APC – ESSAI A TRANSFORMER ?...

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