NA62 straws
Status and plan
Content
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Module assembly and preparation
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Electronics
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Testing, design, procurement
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Stacking
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Shipping
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Technical run
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Excitation of the Argon at the straw wall
Module 1 assembly and preparation
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Both views wired. HV test leak test ok . Except for 3 cells in 2:nd view need investigation
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Module equipped with one final web (New HV connector)
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Plans for technical run
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We plan to equip of subset of the cells (U and V)
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Limited by electronics readout (SRB)
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However, we will connect all cell in terms of gas supply (for safety)
Procurement
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Electronics
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Production of webs and final covers is launched
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The first web batch for September
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Cover for beginning of October . We need to solve rapidly the problem with the oscillations.
Mechanics
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3 additional frames ordered (8 in total)
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Corresponding Manifolds: release option. A contract of 70 kEuros ( decreased by ~30% ). To be placed in the fall.
Example HV testing Module 1, 2:nd view
(first view all cells ok)
Module 2 assembly
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Straw insertion in the first view is ready
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Straw installation of 2:nd view planned for August-September
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Quality the same as Modulel 1 or higher. No straws were replaced in the
1:st view so far!
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Wiring will follow in September/October in order to complete the module at
the end of the year.
Straw straightness (Module ,X, layer 4)
Top
Center
Bottom
Stacking
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Tooling
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Interface parts and all parts are available in 156
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The plans is to start the stacking this week using two empty frames. First module
(X,Y) will be put tomorrow. A second module frame without straws will used to
make a dry assembly
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If all the parts are validated (studs, diemsnions etc) and the procedure
established, the final assembly (planned for beginning of September) will go
quickly
Stacking in preparation
Setting up the 2:nd assembly line in Dubna
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A lot of activities: Training of operator and supervisors, procurement ,
tooling , parts , consumables, shipping…..
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See presentation by Neil.
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All the parts and tooling up to the straw installation and QC will be sent to
Dubna in the first delivery.
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Some tooling and parts will come later e.g. tooling to cut the straws ,webs
wires etc.
Electronics status 1
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Update of the cover
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The new version has been pipelined with the design office and includes (known updates/corrections):
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The modification of LV power supply connector.
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Moving a few tracks interfering with screws heads and printing on the sealing area.
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Replacement of PT1000 0603 package with 0805.
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Removal of HV components and R26 and R29.
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Addition of hole for HV LEMO connector.
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Move of gas connector.
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Removal of SPI/I2C jumper, direct connection to the correct potential.
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Improvement of ground plane around CH7.
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Move of DAC output vias around CH15 protection resistor.
Electronics status 2
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Design of the mezzanine (Georgios).
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There has been some delay, but the plan is to submit the scheme to the design
office before the 10 of August. Basic firmware has been drafted.
Dry run participation
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Georgios will represent the straws in order to learn as TEL62 and to prepare for the
technical run later this year
Proposition:
Déplacer la carte électronique de 300mm vers l’extérieur
et descendre d’environ 40mm vers la chambre, pour
préserver la forme du chanfrein d’angle (c’est ce qui fait
le hors tout de la chambre).
Le fait de déplacer de 40mm vers la chambre, condamne
l’accès à 3 vis de fixation du support sur le flasque de la
chambre.
Pour compenser, on rallonge le support, ce qui nous
permet d’utiliser les 2 derniers trous taraudés du
flasque.
Carte électronique (en vert) déplacée,
Support (en rouge) rallongé, ouvertures
modifiées
Fixation support:
3 vis ne peuvent plus être utilisées
2 vis supplémentaires dans la partie
rallongée du support
Test beam
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Validate the FPGA integrated in the cover. Performance, efficiency noise
behavior etc. Oscillations under certain conditions.
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Running and integration of the Micromegas telescope
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Preparations for the technical run
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Publications !
Note: Straw (NIM) paper in preparation
Metastable Argon levels Problem ?
14
Al Odian and Dave Coward
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Argon and CO2
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Argon has two metastable levels, one at 11.55 ev and one at 11.72 ev.
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A substantial fraction of the energy lost by a particle crossing the gas goes into creating
metastable excitations of the Argon as well as ionization of the Argon. In a straw
chamber, if the excited Argon cannot deexcite by colliding with its companion
molecules,
Can they live long enough to diffuse to the outer wall where they deexcite by releasing
an electron from the outer wall?
A straw chamber is usually run at high gains for which single electrons produce large
pulses. This means that the passage of a particle through the chamber is followed by a
large number of after pulses, which, if the gain is high enough results in a continuous
discharge. For lower gains, there are a large number of after pulses for each traversal of
a particle. Now the numbers: Metastable energies of Argon: 11.55 ev and 11.72 ev
Penning mixtures for metasable levels: CO2 13.77 ev: no! 11.1
ev:C4H10(isobutane):yes
H. Danielsson NA62 Plenary
29/3/12
Investigation
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15
Literature
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Work has been done on the subject
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Study on 64-straw prototype
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We have not seen the effect yet. However, we have the 64-straw prototype
equipped with the covers. We plan to look at this once up ad running.
H. Danielsson NA62 Plenary
29/3/12
Conclusions and plans
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Module assembly procedures are now defined and the assembly line in 154 complete
Some work needed on the services panels and the work to finalize these issues will
start in August (patch panels, services routing, cable trays etc.)
Procurement
 Most of the big contracts placed (Manifolds in the fall 70 kEuros)
 Webs, covers, SRB, mezzanine boards to come…
 We have an issue with oscillation on the cover/CARIOCA which we need to
understand and solve
Tooling and parts to start straw installation in Dubna ready to be shipped. (Module
shipment supports , damping , accelerometer etc in preparation).
The goal is to have the first module assembled up to wiring at the end of the year
The goals is to have 2 modules (1:st chamber) ready at CERN at the end of the year and
the 3:rd started.
Stacking started and on schedule
Dry run and test beam important. Also a preparation for the TR.