Hello, my apologies if you get this twice
Machine (CT):
_ BLAST ps problem works now. Fixed on monday (control/grounding problems,
possible wear and tear)
_ Electrical work on Tx3 done, up to RF people now
_ Coolers back on line
_ Dtunnel power ready for air conditioning
_ operations now running one man shift (with RPO). People stay on call.
Hall access possible but hall opening/search needs extra pair of hands
ABS (GT):
_ Target will not be ready this week, expect tuesday
_ Plan one more cooling test today (cell alignement)
_ needs cell decision
Cerenkov (TB):
_ Will not change noisy tube on L0
Daq (KD):
_ Tried buffering, seems to work for singles
_ needs to test event frag synchronization for coincs
Compton (BF):
_ new pockels cells came in
_ laser and detector work
Bats (WX):
_ Merge code in BlastLib2, hopes to see some results by collab meeting
Neutron (MK):
_ recrunching from dst since yesterday morning (x20 faster than lrn)
IonPol (AkiS):
_ Confirm with Parmela the Tosca prediction about d2-beam
missing 3H target by 2 cm
_ Iron shielding will experience 72 N (~ its own weight) force
from BLAST
_ Too thick Iron shielding will create unwanted fringe fields
Wch (DH): will replace wires in L14
Discussion about 40 and 60 cm cells:
TB: expected target thickness increase is 1.75 in +- 20 cm (cold inlet tube)
_ this was not achieved, possibly because of a built in leak in 60 cm cell
_ A combined analysis of 40/60 cm data with V14 open/closed and for all reaction
channels (ep, eep, ed) by both genya and tb show that "leak" had the effect of
increasing cell conductance by 50 %
_ So for unpol data there was actually no change in thickness at a given flow.
There was some confusion in book keeping
_ For ABS data there was modest increase (20-30%) which may be due to ABS itself
AM: VECTOR polarization results D(eep)
_ Fits vector pol from Pmiss in 0-150 MeV/c range
uses Q2<0.35 data (with cerenkov) and bckg subtraction
_ Data: 47 deg, 40 cm, hPz = 0.42 (Pz=0.65, h = 0.65)
_ Data: 47 deg, 60 cm, hPz = 0.39 (Pz=0.64, h = 0.61)
_ Data: 32 deg, 60 cm, hPz = 0.41 (Pz=0.67, h = 0.61)
_ data has +- 2% error
_ Tensor has too large error bars (+- 10 %)
CZ: TENSOR polarization results D(ed)
_ Data: 47 deg, 40 cm, Pzz = 0.42 (genya 0.49), 35 kC
_ Data: 47 deg, 60 cm, Pzz = 0.27 (genya 0.33), 50 kC
_ Data: 32 deg, 60 cm, Pzz = 0.36 (genya 0.47), 33 kC
_ data have 3-5 % fit uncertainty
_ Above scenario relies on our understanding of the 60 cm
cell problems , and we still expect a 1.75 thickness increase
with 60 cm (compared to 40 cm, both inlet tubes cold)
_ First priority is to measure 1.75 target thickness increase (unpol)
after holes on 60 cm have been plugged !!
SUMMARY TABLE (based on above analysis, relative to 40 cm cell, 47 deg hf):
FOM= Figure of Merit = (relative target thickness) x (polarization ^ 2)
NOte: for 60 cm cell we extrapolate the FOM using a x1.75 thickness increase
Cell/h.f.angle Intensity FOM-V FOM-T
40 cm/ 47 deg 1.0 1.0 1.0
60 cm/ 47 deg 1.75 1.75 0.7
40 cm/ 32 deg 1.0 1.0(*) 1.2-1.4(**)
60 cm/ 32 deg 1.75 1.75 1.4
*) we have never measured d2 vector polarization for a 40 cm cell, 32 deg
holding field angle. However -based on eep analysis results - it is
reasonable to expect no change
**) As in *) for tensor. We may expect an improvement also on the 40 cm
cell with a stronger holding field. We assume it will be a smaller
improvement since there is less depolarization in the 40 cm cell.
_ Please note that for 40 cm cells higher vector polarizations have been
reported (75 % TB, 80 % VZ) while here only 65 % is taken. Either way
the 60 cm cell is preferable in terms of FOM
-- ________________________________________________________________________________ Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124 research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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