2 decay of 150 nd preliminary results phasei data
Download
1 / 13

2 Decay of 150 Nd, Preliminary Results (PhaseI data) - PowerPoint PPT Presentation


  • 55 Views
  • Uploaded on

2 Decay of 150 Nd, Preliminary Results (PhaseI data). Nasim Fatemi-Ghomi. Introduction. Background study of 150 Nd 2 A study of the 207 Bi and 214 Bi background in the e -channel. A study of the 210 Bi, 207 Tl+ 211 Pb and 234m Pa background in the e-channel.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' 2 Decay of 150 Nd, Preliminary Results (PhaseI data)' - kassia


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
2 decay of 150 nd preliminary results phasei data

2 Decay of 150Nd, Preliminary Results (PhaseI data)

Nasim Fatemi-Ghomi


Introduction

  • Background study of 150Nd2

  • A study of the 207Bi and 214Bi background in the e-channel.

  • A study of the 210Bi, 207Tl+211Pb and 234mPa background in the

  • e-channel.

  • Cross check external background with Cu foil.

  • Extraction of half-life of 150Nd2

Data Selection

  • Good betabeta runs between 2019-3395 (phase I).

  • Data taking time =2.8836 x 107s = 0.91 yrs.

  • Events should come from Nd2O3. The foil has 57g mass (37g pure 150Nd).

Analysis tool

Used UCL OO framework written by V.Vasiliev.


207 bi and 214 bi background studies
207Bi and 214Bi Background Studies

  • Pre-Selection Cuts for e-channel:

  • One negatively charged track

  • associated with an isolated PMT

  • Ee > 0.2 MeV.

  • Only one  cluster with E> 0.2MeV.

  • No other  with E> 0.15MeV.

  • Internal TOF hypothesis for e events > 5%

  • External hypothesis < 1%.

  • Tracks must have one hit in one of the two first layers of GG.

cos(e) < 0.9


Activity of 207Bi

In addition to the pre-selection criteria described there should not be any single or

group delayed hit(s) in the tracker.

Fit 207Bi with the data minus background


Look at the energy region 0.7 MeV< Ee <1.1 MeV and 0.25 MeV< E <0.6 MeV

where 207Bi dominated over all other backgrounds.

A207Bi=13.4 ± 0.3 mBq ~ 235 ± 5 mBq/kg


Activity of E214Bi

Find the activity looking at events with an  (delayed or single hits.)

A214Bi = 0.87  0.17 mBq ~ 15.26  2.98 mBq/kg


Find the activity using all the events: E

A214Bi = 0.86  0.06 mBq ~ 15  1 mBq/kg


1e Channel E

  • Selection cuts:

  • One track with negative charge associated with isolated PMT.

  • Track has to have a reconstructed vertex.

  • Ee > 0.5 MeV.

  • Track has to have a hit in one of the first two layers of GG.


External background E

The external background activity found by V.Vasiliev is checked with looking at the energy distribution of the energy of e-  events coming from the Cu foil.

Data = 35524±188, Total Background=34251± 382

Data-Background= 1273 ± 425 -> has to be added to the systematic uncertainty.


External Background & E

Background on the Surface

of the Wires and Foils.

Internal Background

Found by

V.Vasilev

checked

with Cu foil

Slide 9


150 ENd Half-life

Pre-selection for 150Nd to 2 events:

  • Two negatively charged tracks associated with isolated PMTs and

  • E1 ,E2 > 0.2 MeV.

  • Both electrons originate from a common vertex

  • with |∆r| < 2 cm & |∆z| < 4 cm.

  • Internal TOF hypothesis > 4% & external TOF hypothesis < 1%.

  • Track starts from layers 1 & 2 of GG.

  • No delayed alpha decay with refiring time > 70 s.

  • No single or group delayed hit(s).


Results E

Number of data events: 1011

Number of total background: 315

Efficiency =133643/2000000 6.68%

T12= 9.04 -0.57+0.63(stat)  0.51 (act)  0.78 (syst) x 1018 y

1.11e-19

0.030

0.01988

9.22e-4


Summary E

  • Looked at e-, e--, and 1e channels to find the activities of

  • contaminants in the 150Nd foil.

  • Looked at e- channel in Cu to cross check the external, surface of

  • the wire and surface of the foil backgrounds.

  • Extraction of the half-life.

  • Have to start working with Phase II Data!!


ad