7\. **Analog Sensor Studies**

Along with the DCOPS optical sensor testing, we tested a prototype CMS

Z transfer (-X survey) between a reference MAB surface and the Transfer
plate

system (ET1/ES1 mechanical link), a dual axis inclinometer on the
Transfer

plate (Applied Geomechanics 900) to define its orientation with respect
to

gravity (Θ,Φ), plus a prototype CMS R transfer (+Y survey) between the

Transfer plate system and a mock ME2/2 outer boundary (CSC panel) plus

a prototype R connection between a mock ME2/2 inner boundary and a

ME2/1 outer boundary. ME2/2 was simulated by a 50 mm wide, 3.2 m

long strip of CSC panel. It may not be a good representation of a CSC

assembly because of thermal flexure and free expansion.

The MAB Z connection was a distance measurement between an

OMRON Z4MW40 laser distance sensor and a MAB surface about 45 mm apart.

The sensor was mounted on the end of a 1168 mm (1175 mm july-sept)

Aluminum tube. The other end of the tube contacted a spring loaded
potentiometer

LCP8-10 mounted on the Transfer plate and measuring the gap to the tube.

There were two temperature sensors T1 and T2 on the two ends of the
tube.

They tracked each other extremely well and provided temperature
monitoring

to 0.1 deg K.

The R connections were done with wire extension potentiometers

LPXA-2 (50 mm stroke). All of these devices are voltage output devices.

Finally temperatures around the setup were measured with Analog

Devices AD592 current source devices (1 μamp/deg K) which terminated

on voltage dividers near the DAQ giving 10 mv/deg K. All of the sensors

were read out as analog voltages by an HP 34970A data acquisition/switch

system which scanned the sensors through an ADC to a serial port of

the DAQ computer. It also provided timing (gating) of the lasers in
DCOPS

measurements. With the low pass filtering installed (determined by tests

at Fermilab), we were able to limit noise effects (ADC fluctuations) on
our

distributed system (15 m lines) to ± 0. 75 mv.

We had calibrated all these sensors at Fermilab and the results are

available
\@http://home.fnal.gov/\~leer/calibration/ISR_Analog_Sensor_Setup.htm

The effective calibration of these sensors is given in the following
Table MM.

The Transfer plate inclinometers are (x = θ, y = φ). The Z4MW40 is the
laser

distance sensor to the MAB, ZLCP8-10 is the gap potentiometer between
the

Transfer plate and the Z tube, RLXPA-2-1 is the R transfer potentiometer

between ME1/2 and ME2/2 CSCs, and RLPA2-2 is the R transfer
potentiometer

between the Transfer plate and the ME2/2 CSC.

Typical temperature coefficients are (for inclinometers) span +0.03%/deg
C

and zero 10-20 arc seconds/deg C, for LPX2A potentiometers +0.03%/deg C,

for LCP8-10 potentiometer 400 ppm/deg C, for Z4MW40 laser distance
sensor

.03%Full Scale/deg C (for sensor and for amplifier). For our three test
periods

in I4, the temperature varied at most 1.5-2 deg C overall and in each
period.

All the analog sensors were referenced by a very stable 12 V DC power
supply.

**[Table MM. Analog Sensor Conversions]{.underline}**:

θx(tilt)(arc deg) = 10.4739Vx -- 0.0963Vx^2^ -- 0.1714Vx^3^ +
0.0025Vx^4^ + 0.0026Vx^5^

θy(tilt)(arc deg) = 10.5002Vx + 0.1549Vx^2^ -- 0.1942Vx^3^ -
0.0037Vx^4^ + 0.0062Vx^5^

Z~Z4mW40~ (mm) = (V~Z4M~ + 16.180)/(0.4038) + Z~Face\ position~

Z~LCP8-10~(mm) = (V~LCP8~)/(1.0987) + Z ~free\ point\ position~

R~LX-PA-2-1~ (mm) = (11.928 -- (V~LX-PA-2-1~))/(0.2202) + R
~Zero\ Extension~ (ME2/1-ME2/2)

R~LX-PA-2-2~ (mm) = (11.928 -- (V~LX-PA-2-2~))/(0.2188) + R
~Zero\ Extension~ (ME2/2-Tr Plate)

Tn (deg K) = (V~Tn~ -- offset(n))\*100 where o(n) = 0.007, 0.032, 0.034,
0.032,

0.033,0.035 for n = 1,..,6

They are all very linear except the inclinometers which have some
polynomial

corrections for fluid vessel shape. All sensors have small thermal
coefficients.

Periodically we did special "burst" runs of rapid multi measurements of

analog sensors only. These define the short term (instantaneous)
resolution of these

sensors. These runs are time stamped, so they can be used for long term

studies. Tracking the burst measurements throughout the running periods

provided a redundant high statistics test on long term stability/drift
to compare

to normal data samples. Typically, we took two hundred measurements in a
burst run.

For short term resolution estimates we took the worst standard
deviations found in any

Run as the guaranteed short term resolutions. The instantaneous
resolution results are

given in the following Table NN.

**[Table NN - Short Term Resolutions]{.underline}**:

σΘ~x~(Xtilt)= σφ~y~ (Ytilt) = 0.52 mv = 19.54 arc sec 12 V Analog
Reference σ = 0.567 mv

σZ4M-MAB = 0.778 mv = 1.93 μm σLCP8-10 Z-Trans Plate = 0.517 mv = 0.5 μm

σME2/2-Trans Plate R= 0.523 mv = 2.4 μm σME2/2-ME2/1 R =1.039 mv = 4.7
μm

AD592 Temperature sensors σ = 1.032 mv = 0.10 deg K (typical 0.05 deg K)

We have taken measurements of the analog sensors each time we took any

measurements (any laser combination) of the DCOPS sensor lines.
Typically,

eight analog measurements are made in a DCOPS cluster measurement. These

measurements were used in each test period (about one week) to determine

Intermediate sensor resolutions (with/without thermal drift
corrections). All

sensors show some small thermal dependence. Also our mechanical rulers;

the Z tube and the ME2/2 CSC strip expand/contract in di urnal thermal
cycling.

The Raw analog (no thermal drift corrections) standard deviations of
measurements

for the three test periods are given in Table PP below:

**[Table PP - Intermediate Term Resolutions]{.underline}:** (one run
period \~week)

Use data from normal cluster runs (cycles 8 measurements every 15 min);
**no**

**corrections**, all points are **raw** data (LM302 off -- 4
measurements /cycle):

Period σXtilt (Θ) σYtilt (Φ) Z4M-MAB 12V Ref

June σ = 116.75 arc sec 58.31 arc sec 18.04 μm 1.06 mv

(3.11 mv) (1.55 mv) (7.25 mv) \*

July/Aug σ = 97.23 arc sec 58.31 arc sec 32.22 μm 0.50 mv

(2.59 mv) (1.55 mv) (12.95 mv)

Sept σ = 97.23 arc sec 19.56 arc sec 46.19 μm 4.17 mv

(2.59 mv) (0.52mv) (59.58 mv)

Period LCP8-10 (Z~TP~) ME2/2-TP R ME2/2 -- ME2/1 R

June σ = 23.60 μm 14.03 μm 68.25 μm\*\*

(25.90 mv) (3.07 mv) (15.03 mv)

July/Aug σ = 28.80 μm 18.92 μm 44.70 μm\*\*

(31.60 mv) (4.14 mv) (9.843 mv)

Sept σ = 11.80 μm 14.21 μm 75.29 μm\*\*

(12.95 mv) (3.11 mv) (16.58 mv)

\* Partial period data

\*\* Connected to free floating end of3.2m long CSC panel strip (50mm
wide)

Finally, we have combined the analog sensor measurements (LM302 laser
off) of

the three separated test periods in real time. From the combined file,
we determine the

raw standard deviations (resolutions), the long term drifts, comparisons
to temperature

sensors, and drift corrected standard deviations. The resolutions are
given in Table QQ below:

**[Table QQ -Long term Resolution]{.underline}**: June-July-August-Sept
Data -- fit across 8.51M sec

All data; **no corrections**, no drift removal; other than ∆V shifts for
LM302on data

Xtilt σΘ~x~ = 0.018835 arc deg (1.13 arc minutes) 12 V Ref σ~LV~ = 2.61
mv

Ytilt σΦ~y~ = 0.040467 arc deg (2.43 arc minutes)

Z4M-MAB(JulyAugSept) σZ4M-MAB = 101.44 μm

LCP8-10 Z-Transfer Plate(JulyAugSept) σLCP8-10 (Z~TP~) = 15.27 μm

ME2/2-Transfer Plate R σ ME2/2-TP R = 40.27 μm

ME2/2 Inner -- ME2/1 Outer R σ ME2/2-ME2/1 R = 112.94 μm

Looking at all the sensors, we can see them track/react to the average
temperature

changes in the different test running periods. Unfortunately, we did not
have a MAB in

June, so we only have comparable Z4M-MAB and LCP8-10 data for two
periods, so

we don't have tracking proof positive in these cases as for sensors in
three periods.

Also the ME2/2-ME2/1 R connection was changed in
September.***Disregarding any***

***of the drifts as temperature correlate**d*, sensor Drift Limits are
established by

a linear fit of June-July-Aug-Sept Data plotted in real time across
8.51M sec and are

given in Table RR below:

**[Table RR -Long Term Drift Limits]{.underline}**:

Xtilt Θ~x~ = -0.21259 arc deg -- 1.1995e-08 arc deg/sec (0.170 arc deg
in 8.51 M sec)

Ytilt Φ~y~ = 5.3311 arc deg -- 1.5176e-08 arc deg/sec (0.129 arc deg in
8.51 M sec)

Where local T3 (shift) as a drift is T3 = 289.78 -- 9.2574e-08 deg K/sec

Z4M-MAB\* = 47.387 mm + 1.9962e-08 mm/sec ( 93 μm in 4.64 M sec)

ZLCP8-TP\* = 8.6263 mm -- 3.527e-09 mm/sec ( 16.4 μm in 4.64 M sec)

ME2/2-TP R = 11.036 mm + 8.859e-09 mm/sec ( 75.3 μm in 8.51 M sec)

ME2/1-ME2/2 R = 38.954 mm^+^ -6.2823e-08 mm/sec \*\* (251 μm in 4.1 M
sec)

\* July-Aug-Sept periods

\*\* There is thermal motion (wiggle/expansion) of the 3.2 m long free
panel connected to the sensor

^+^ June-July-Aug periods

All of the temperature sensors across the ISR test periods can be fit
with a variation like

1e-07 deg K/sec and all of the analog sensors that are fixed to stable
objects show a variation

like 1e-08 unit/sec.

A simplest correction for thermal effects on the analog sensor readouts
would be to take

the average of sensor readings and temperatures in each test period;
choose one as a reference

and see if the variances are consistent with the sense and magnitude of
temperature differences.

We can try this procedure for three sensors that have data and invariant
conditions in the three

test periods; Xtilt Θ~x,~ Ytilt Φ~y,~ ME2/2-TP R. Table SS gives the
results below:

**[Table SS -Long Term Drift Limits with Simple Temperature
Correction]{.underline}**:

Xtilt Θ~x~ = -0.23747 arc deg -- 9.1024e-10 arc deg/sec (0.0077 arc deg
in 8.51 M sec)

Ytilt Φ~y~ = 5.3091 arc deg -- 5.2444e-09 arc deg/sec (0.0446 arc deg in
8.51 M sec)

ME2/2-TP R = 11.056 mm -7.2693e-11 mm/sec ( 0.62 μm in 8.51 M sec)

With the resulting Long term resolutions

Xtilt σΘ~x~ = 0.0367 arc deg (2.202 arc minutes)

Ytilt σΦ~y~ = 0.0097 arc deg (0.582 arc minutes)

ME2/2-Transfer Plate R σ ME2/2-TP R = 4.70 μm

Even with the simple temperature correction, long term dirfts are
dramatically reduced

and the effective long term resolution is improved significantly. In the
future, we will calibrate

the temperature dependence of our sensors through detailed temperature
cycling. Then we can

apply a real time correction according our T sensors which will improve
the resolution and

stability even more.

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height="8.802083333333334in"}

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10\. **Acknowledgements**

We especially thank our collaborators of Northeastern University

(J. Moromisato, Eb vonGoeler, R. Terry) who built the mechanical parts,
calibrated

and filtered the DCOPS sensors, and worked with us in the development,
setup,

and some execution of the tests.

We also thank S. Hanson, E. Cowden, J. Lofgrin, R. Martin (Fermilab PPD

Electronics group) and V. Sknar, E. Orischin (Petersburg Nuclear Physics
Institute)

for their development, construction, testing,DSP programming, etc. of
the DCOPS

sensor and electronics for the ISR I4 tests.

We thank the CERN Laboratory EP/CMS (A. Ball, D. Arevalo, R. Riberio)

for establishing the ISR I4 test area, utilities, supports; for survey
services and

Photogrammetry (C.Lasseur, C. Humbertclaude, D. Mergelkuhl, R. Goudard,

J.Noel. Joux and crew- CERN Geodesy). We also thank the Fermilab Geodesy

(J. Greenwood and crew) for Photogrammetry measurements of our sensor
assemblies;

and the Fermilab Technical Division for CMM measurements of brackets and
the transfer

plate.