Status Report of activities in LNF Soldering procedure 1.Status of soldering machine 2.Measurement of wire position Chamber prototypes 1.Construction of new prototypes 2.Possibility of opening the chambers 3.Status of mould 4.Mini-ageing test Chamber panels and quality control 1.Planarity measurements 2.Frame height respect to cathode 3.Radiation resistance 4.Thermal resistance LHCb Muon meeting – CERN Jan 30, 2002 (C.Forti, A.Saputi)

Soldering machine 1.Status of the setup Final mechanics ready (see pictures) One head completely assembled and operational Labview software (IMAQ of National Instruments) for soldering and automatic wire pitch measurement under preparation (~ 15 days required) 2.Short film 3.Next steps Soldering tests on larger scale (up to 150 cm) 2 nd head (ready in ~ 2 months) Study of the possibility to determine automatically the soldering quality using reflection of light.

Soldering test

Control of wire positions A frame wired at CERN was transferred on a “dummy” chamber. We compared the measurements of the steps between 140 contiguous wires, from a set of 140 soldered wires (139 steps), obtained from the camera of the soldering machine (in pixel) and from an independent optical measurement (in micron). We found the best conversion factor: 12.5 micron/pixel. We converted the camera measurements from pixels to microns and compare the two measurements (in micron). Conclusions: 1.Excellent agreement between analog and digital measurements: the 2 methods show the same RMS; RMS of difference analog – digital = 17 microns; then we can estimate RMS of digital measurement ~ 12  m 2.Only one wire over 140 is in bad position (easily identified).

Step between wires: conversion from pixel to micron The ratio analogic/digital has a very small RMS 0.09 micron/pixel !!

Step between wires: analogic vs. digital measurement

Step between wires: comparison of analogic and digital mean RMS

Step between wires: difference analogic - digital

Construction of chamber prototypes 3 quadrigaps wired at CERN (10-20th december) (each of area ~ 28x34 cm 2 n.tot wires=1920) 2 of them have been tested and assembled: each single gap (without cover) tested at HV=3.2 kV in air: current is 0 nA assembled (not glued yet) and tested at 3.0 kV (no current) Wires of third quadrigap are being currenlty soldered (ready in few days). Including the quadrigap previously constructed, we will have a total number of 2560 wires, equivalent to one large chamber. Up to now:no wires broken no HV problems never current going up These prototypes were very helpful in understanding construction procedures and HV critical tests.

Test on possibility of opening the chambers As you know, Frascati approach is to use glue for closing the chambers. We are considering the possibility of opening the chambers in case of malfunctioning, using a circular cutter to remove the glue (see drawings). The conclusions of a first test are encouraging: the operation is easy; it is easy to re-close the chamber (usual gluing procedure); the cutter will be provided with a exhaust fan (low dust); short time needed: few minutes.

Test on possibility of opening the chambers

Status of the new mould (big one) Mould for M3R3 chamber: the company has straightened the mould planes (in Al alloy); within a few days, the mould contruction will start (about 20 days required); then, we will start production of large panels (150 x 40 cm 2 ) 1500 mm 500 mm

Ageing test with X rays A B C D 5.9 keV X ray Gaps A and 3300 V, irradiated for 1 month (21 dec-21 jan). They were always on. We monitored the currents in gaps A and B 5  A 15 nA Dose = 5.7  A x 30 days = 14.8 Coulomb The irradiated zone was too large = 3x3 cm 2. So we have ~ 65 cm of wires irradiated. Dose/cm of wire ~ 0.23 C/cm of wire, corresponding to : 4.6 LHC years equivalent in M1R3 or M2R1 while a 10 years test is necessary.

Ageing test with X rays: currents Relative variation of currents, in gap A (TOP) and B (BOTTOM) in one month of test (~ 720 h). Currents always went to 0 when switched off Gap A was stable over this period. The behaviour of Gap B is not well understood. The current was too low and gap B could not to be used as reference. Attenuation from A to B was ~ 300, while ~ 10 could have been OK.

Our ageing test is encouraging, even if not conclusive: the current in Gap A (at 3.3 kV) is stable over one month of test, equivalent to ~ 4.6 LHC years. There is the possibility to perform a complete ageing test, using the Co60 source at ENEA-Casaccia. The distance of the detector from the Co60 sources can be changed to tune the current drawn in test and reference detectors. However, this test is expensive: negotiacions are pending. Ageing test with X rays: conclusions

Chamber panels Total number of panels produced: 52 panels (28 x 34 cm 2 ) Now, we check systematically the panel quality (from last 22 panels produced) Measurement of planarity 1.all panels measured, just after delivery 2.2 panels: after thermal stress (oven and/or refrigerator) 3.3 panels: after radiation stress (gammas of Co60 source) Height of HV bar respect to cathode Tests of fire resistance are being performed by italian fire corps Mechanical tests (Will be performed in Potenza in the first half of february) 1.Flatwise tensile strength (ASTM C297) 2.Flatwise compressive properties of sandwich cores (ASTM C365) 3.Flexural properties of sandwich constructions (ASTM C393) 4.Facing cleavage of sandwich panels (ASTM E2004)

PANELTYPEPRODUCTION DATEDESTINATION 1PAD30-NOV-01PROTOTYPE CONSTRUCTION 2PAD30-NOV-01PROTOTYPE CONSTRUCTION 3PAD30-NOV-01PROTOTYPE CONSTRUCTION 4GROUND30-NOV-01PROTOTYPE CONSTRUCTION 5GROUND30-NOV-01PROTOTYPE CONSTRUCTION 6GROUND30-NOV-01PROTOTYPE CONSTRUCTION 7GROUND30-NOV-01PROTOTYPE CONSTRUCTION 8GROUND30-NOV-01PROTOTYPE CONSTRUCTION 9GROUND30-NOV-01PROTOTYPE CONSTRUCTION 10GROUND30-NOV-01PROTOTYPE CONSTRUCTION 11GROUND30-NOV-01PROTOTYPE CONSTRUCTION 12GROUND30-NOV-01PROTOTYPE CONSTRUCTION 13PAD4-DEC-01PROTOTYPE CONSTRUCTION 14GROUND4-DEC-01OVEN (70 C) + MECHANICAL TEST 15GROUND4-DEC-01PROTOTYPE CONSTRUCTION 16GROUND4-DEC-01PROTOTYPE CONSTRUCTION 17GROUND12-DEC-01RADIATION TEST (10**4 Gray) 18GROUND12-DEC-01RADIATION TEST (10**4 Gray) 19GROUND12-DEC-01MECHANICAL TEST 20GROUND12-DEC-01MECHANICAL TEST 21GROUND12-DEC-01OVEN (40 C) + MECHANICAL TEST 22GROUND12-DEC-01RADIATION TEST (10**4 Gray)

Planarity measurement: method From a set of measurements(x,y,z) defines a reference plane For 65 (x,y) values,measures the distance of the point from the plane 16 points belong to panel border and show larger deviations from the reference plane

Planarity measurements: all panels together ~ 1800 points measured For each panel, if we exclude the points nearest to the border (at ~ 18 mm from it), we get RMS=16.6  With the border included we get RMS=26.9 

Planarity measurements: best panel (n.18) GROUND Side 1 Side 2

4 panels with frames For each panel we measured 12 points (6 on each side) glue HV bar panel Precise bar 2.49 mm Check of HV bar positioning

Frame height respect to the cathode Well within specs Could be better with a rectified bar

Radiation test at ENEA Casaccia (near Rome) with a powerful Co60 source E  =1.25 MeV; the source can operate at 10 4 Gray/hour = 1 Mrad/hour. We chose to irradiate 3 panels at ~80 cm of distance (400 Gy/hr), because a smaller rate causes a bigger damage in polyurethane (Schonbacher and Tavlet, CERN). Test duration ~ 25 hours Total ionising dose ~ 10 4 Gray. Radiation test setup

Radiation effect on planarity: panel 17 (GROUND)

Thermal effect: 77 hours at 62 degrees

First test on final setup of the soldering machine are positive and confirm validity of technical choices Panels are (slowly) continuing the quality tests: no problem found up to now; in the meantime the production has reached a good quality (at least for small ones) A “mini” production of chambers has taken place, where procedures and quality tests have been “trained”. We can afford now with more confidence the construction of larger chambers Conclusions