Systematic issues old

1
Systematic issues old new
update this !
Generic classification of lifetime distortions
2
Wall stops

• Cause
• TPC cathode inefficiency
• TPC reconstruction ambiguity !
• ?
• Effect on l
• Needs to be studied.
• Worst case assumption f_wall lt 10 ppm
• How to quantify
• fit start time scan
• comparison different fiducial cut
• study TPC cathodes with FADC
• ?d

• Future work
• MuCap study and note required

3
Transfer to Zgt1
r_tr transfer rate in 105 ?s-1 at LH2 density,
xr_tr? c/r0 (ppm), r_cap capture rate, yr_cap
/(r0r_cap), Yxy capture yield in ppm, dr
relative change of observed decay rate, c
impurity concentration
All rates in this paper are given in units of
?s-1, capture yields Y, change of decay rate dr
and concentrations c in ppm.
Ratio to pure exp
1
dr xy(2y)/(1y)2 ? 2 xy 2 Y
T (ms)
4
Transfer to Zgt1
Without correction. Assume we achieve cNlt0.01 ppm
in the future, as determined by chromatography.
Then we must demonstrate cOlt0.003 ! With
correction Assume we achieve clt0.01 ppm
overall. a.      External diagnostics If we know
the concentrations to 20 then we need to
calibrate the effect of the impurities to 20,
because of possible uncertainties in transfer
rates. Again the H2O problem is difficult for
chromatography. b.     Zero extrapolation based
on yield The relation between dr and
experimental yield can be expressed as dr Ye
f(yZ) / ?ZBoth Ye and dr scale linear with x,
because it is a small parameter. f(yZ)
(2y)/(1y)2 changes only by 6 between O and N.
?Z characterizes the capture detection efficiency
for different impurities, should also be similar
for O and N.

• Workgroup discussion and MuCap note
• Which of these requirements can be achieved?
• Systematic problems in capture diagnostics with
  TPC, FADC !!!
• prepare samples and plan calibration
  measurements at the end of the run
• How to calibrate O2, H2O?
• can FADC info be used for determination of the
  composition?

5
Transfer to D
transfer pm d ? dm p (134 eV)
Ld f cd ld 150/s cd(ppm) proposed
dl10/s
Special presentation later

• Workgroup discussion
• Realistic plan (work and time) for conditioning
  and testing full system well before the run !!!
• Detection methods
• Correction methods
• PNPI isotopic separation
• Plan/ coordination for protium production

6
Sys. Issues
7
Simulation with MuCat

• MuCap conditions f 0.01, cd 1 ppm

http//www.npl.uiuc.edu/kammel/doc_mucap/scat/sca
t.html
8
High statistics simulation (convolution)

p(t,r)?0r g(r,t) dr cpdf
g(t,r) dm radial pdf
r (mm)
T (ms)
http//www.npl.uiuc.edu/kammel/doc_mucap/scat/sca
t2.html
9
time spectra
fits
D correction to exponent

• Change from pure exponent

10
Fits
1010

cd (ppm)red 0.1black
1.green 5.blue 10.
6 108
whats our effective r without cuts?
http//www.npl.uiuc.edu/kammel/doc_mucap/scat/sca
tt.html
11
Zero extrapolation

• Define
• x axis l(r20)-l(r100)
• y axis l(r100 mm)
• cd1, 5, 10 ppm higher values with 109 stat

where cc2/c1
total error due to extrapolation ?5.9 s-1
http//www.npl.uiuc.edu/kammel/doc_mucap/scat/dst
udies.pdf
12
Accidentals

• Different selection criteria
• signal/noise eSC eSC x ePC full tracking
• Effect on l
• Which non flatness is acceptable?
• What physics effects could cause non flatness.
  (Ion source variations )
• How to quantify
• different electron selections
• fit of accidentals before time zero
• ?

See also instrumental effects section
13
mSR
? 13.55 kHz/GaussMu 1.394 MHz/Gauss R(t)1a
P(t)?u
l fit N(f)N(fp), l- fit N(f)-N(fp),correct
l

• MuCap note and discussion
• importance of Bz?
• which fraction of data with reversed field
• analysis correction procedure
• determine B field direction?

14
Detector/DAQ effects
First consider only good events
(m1,e1) self correlation
t
(m1,e1) (m2,e2) double correlationaccidental
distortion (m1,e2) real distortion (m1,e1)
influenced by other pair
(double kill)
Allow also wall stops
(m1,e1) (m_wall,e2) m_wall can be mistaken as
m1
15
Toms list additions

• MuCap Run7 Data Afflictions
• muSC misalignment in Clean Fill 1 prevented
  effective global PP.
• muSC afterpulsing in ostensible deadtime
  interval.
• CAEN 1 mistiming The CAEN module receiving the
  eSC signals occasionally gained a clocktick in
  the TDC 0 IU signals (or, equivalently, lost
  clockticks in the TDC 1,2,3 signals), producing
  a "shadow band" in eSC coincidence plots
  involving the IU detectors. I skipped any
  blocks which suffered from this problem.
• Blocks containing significant CAEN, COMP, or
  TDC400 errors were cut.
• Blocks containing ePC1 sparks were cut.
• ePC1 afterpulsing was a problem--there was a lot
  of long timescale afterpulsing evident in the
  Run7 data. The problem was so pervasive that no
  specific workaround was implemented.
• Occasional MIDAS data block duplication.
• additional
• 50 MHz signal in time spectrum

Workgroup How serious for lifetime? How to
improve ?
16
m-e Self correlation

• Cause
• detector cross talk??
• electronic cross talk??
• DAQ cross talk??
• Effect on l
• Needs model
• How to quantify
• accidentals in different electron detector
  systems, how to include tagged signal,
  required statistics etc.Discuss in Workgroup

17
Double correlation

• Accidentals P are acceptance probablities
• Pa(te2-tm1) p(te2-tm2)Pm(tm2-tm1)
• Any Pm correlation leads to accidental
  distortion.
• make Pm correlation short global PU needs full
  - 24 us drift time better coincidence
  definition at TPC entrance
• good PU signal (mSC, mPC, hardware PU)
• can measured Pm correlation be used?
• local PU analysis tricky Tom Case TPgood
  matching muon vectorsmSC with TPC

18
Double correlation
Real mp events Double kill Distortions if
Pe(te1-te2) depends on (tm1-tm2)
Pem(te1-te2, tm1-tm2) ?0 Simple example
Pm(tm1-tm2) d (tm1-tm2) e.g. by imperfect
PUPe(te2-te2) by deadtime e.g. cathodes slow
(1.5 us), eSC 40 ns presently Strategymake Pm,
Pe as small as reasonably possible mp and wall
stop eventsmisidentification of m wall by
presence of good m, fiducial cuts dont help
Workgroup and MuCap Note Analytical formulation
(again) Realistic and fast Monte Carlo!!
19
Clock, differential linearity
Workgroup, see also Kevin Lynch Note
20
Summary

• Significant detailed studies still required.
• MC will play an important role.
• It is essential to bring ideas to paper (MuCap
  notes). Many issues intellectual challenges.
  Need focus, in competition with hardware work.
• I will make list of issues and contact
  candidates to work out specific studies.