Attachment 'adjust2007.txt'

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   1 Time-stamp: <23 Jun 2007 12:37:13 CEST by Sebastian Schaetzel>
   2 This document can be found at http://www.desy.de/~sschaetz/hcal/tb-cern/
   3 
   4 0. Get familiar with the CMB
   5 
   6    look at the picture at http://www.desy.de/~sschaetz/hcal/tb-cern/cmb.jpg
   7 
   8    LED numbering: top LED is LED 0, counting down to LED 11;
   9    lowest LED on upper CMB half is LED 8, LEDs 9 to 11 are on lower half
  10 
  11 1. Include module in DAQ
  12 
  13    edit AHC.cfg, set hold for CM to 100 ticks
  14    switch LV on
  15    startUp
  16    runStart -t ahcCmLed -w
  17 
  18 2. Check Tcalib signal at module connector (5 minutes)
  19 
  20    use scope with probes
  21 
  22    Tcalib=4th connector hole from bottom, right position should switch to
  23    higher voltage for approximately 1 microsecond
  24   
  25    Vcalib=3rd connector hole from bottom, right position should have positive level 
  26 
  27 3. CMB installation (10 minutes)
  28 
  29    get a new CMB
  30  
  31    Check jumper settings for CAN bus behaviour
  32       2 jumpers near the blue dip switch:
  33       J011: centre pin must be connected with left pin (o-o o), or
  34             jumper fully open (o o o)
  35       J01(hole): centre pin must be connected with right pin (o o-o),
  36                  or jumper fully open     
  37   
  38    CAN bus position and address
  39       Every CMB needs a unique CAN bus address; it is set with the
  40       blue dip switches (only the rightmost 8 switches are used)
  41  
  42       Convention: the CAN bus address is set to the number
  43       of the module to which the CMB is attached.
  44 
  45    physically readjust LEDs and PIN diodes so that they stick out
  46       through the holes of the CMB housing by the same length
  47 
  48    switch off CMB voltage (at Slow Control)
  49 
  50    switch off SiPM HBAB high and low voltage (at Slow Control)
  51 
  52    mount the CMB physically to the module
  53       use the four brass screw connectors as guidance
  54 
  55       the LEDs generally fit well into the holes, be careful about the
  56       PIN diodes. For some CMBs it helps to lift the CMB up a little
  57       when pushing it (gently!) towards the module.
  58 
  59       tighten the four screws at the outer part of the housing
  60 
  61    connect the PIN diode readout cable ***ESSENTIAL***
  62       The two PIN diode read-out HBABs are located on top of the
  63       module stack. Connect a PIN diode read-out cable to the CMB.
  64       Put the cable number in the AHC.cfg file. (There is a script
  65       which uses AHC.cfg as an input and creates the correct mapping
  66       of the PIN diodes in the HCAL database.)
  67       
  68       The PIN diode read-out cable is NEEDED to equalise the grounding
  69       of CMB and HBAB! Do not switch on the module LV without having 
  70       connected the PIN cable or unless you have equalised the ground
  71       by other means! Different grounds can destroy the
  72       V_calib/T_calib sender on the SiPM HBAB.
  73       
  74    connect the CMB power cable
  75       use the power connector which has the same number as the CAN bus position
  76       connect it to the connector on the top side of the CMB which is
  77       away from the module
  78 
  79    connect the CAN bus cable
  80       "Daisy chain": the CAN bus is guided through the
  81       CMBs. Make sure the chain is not interrupted. The CAN
  82       bus must be terminated after the last CMB with 
  83       a termination adaptor. 
  84 
  85     switch on the SiPM HBAB low voltage
  86       
  87     switch on the CMB voltage
  88 
  89     Test the CAN bus connection
  90        click "CHECK" button on Slow Control CMB main panel 
  91 
  92        recognised CMBs (labeled according to the CAN bus position)
  93        appear green; check if newly connected CMB is seen
  94        if not, check dip switch settings, CAN cabling, jumper settings
  95 
  96 4. Check LED position and width (20 minutes)
  97     
  98     start LED run: runStart -t ahcCmLed -w 
  99 
 100     set the LED amplitude from the Slow Control
 101        detailed CMB panel, press "Ampl DAC, width DAC" button in
 102        "Pulser settings" box 
 103 
 104        enter 255 in the amplitude field
 105        enter 120 in the width field
 106 
 107        DAQ Vcalib value is ignored now
 108 
 109        make sure all LEDs are enabled (yellow button)
 110 
 111     connect scope
 112        use probes and check that they are connected with 1MOhms termination
 113 
 114        The single vertical pins on the CMB provide the CMB ground;
 115        connect the probe ground to one of these pins.
 116 
 117        connect probe to Tcalib at connector from module (fourth pin
 118        from below), use start of Tcalib as trigger (rising edge)
 119 
 120        connect two other probes to the two legs of one LED
 121        subtract the two LED signals with the scope MATH function
 122        such that resulting signal is positive for the pulse
 123 
 124        Measure the delay of Tcalib to LED pulse (the red MATH result
 125        of subtracting the two signals at the legs):
 126           - press the zoom button on the scope (magnifying glass), screen will divide
 127 	  - use horizontal position knob to bring the red pulse to the centre
 128 	    (press "coarse" button for coarser steps)
 129 	  - adjust the horizontal scale to 10ns per division
 130 	  - at the bottom of the screen, the time between the trigger
 131             and the centre of the screen is displayed.
 132 	    put this number in a table:
 133 
 134 	    LED         0   1   2  .... 11
 135 	    delay (ns)
 136 	    width (ns)
 137 
 138 	    The delay is in the range of 110-160 ns.
 139 	    The delay difference between channels must not be
 140 	    greater than 5ns. If it is greater, ask Ivo Polak to readjust
 141 	    the delay.
 142 
 143 	    Also note the width of the red signal in the table. Adjust
 144 	    to 10ns if necessary according to the following procedure:
 145 	   
 146 	    Ajusting LED pulse width:
 147 	       The width common to all LEDs is send via the CAN bus
 148 	       from the Slow Control (the field that was set to 120). 
 149 	       
 150 	       To adjust the width individually for every LED, use
 151 	       the second trimmer (the one on the right when the CMB
 152 	       is laying in front of you). Turn clockwise to increase width.
 153 	       Adjust to 10ns at FWHM of the red curve on the scope.
 154 	       Note that the red curve is negative before the actual pulse.
 155 
 156 	       Caveat: For some CMBs, the range in pulse width that
 157 	       can be covered with the trimmer is different. It might
 158 	       not be possible to adjust all CMBs to 10ns for the 120
 159 	       DAC width sent from the Slow Control. You then have to
 160 	       experiment with the DAC width, or ask Ivo Polak to
 161 	       equalise the range.
 162 	        
 163        Disconnect the LED leg probes, keep the Tcalib trigger
 164 
 165 5. SiPM Calibration mode hold scan (10 minutes)
 166 
 167    connect scope to analogue out of one SiPM HAB 
 168    switch scope to non-zoom mode
 169    
 170    switch on SiPM HV for the modules that have the DAC settings loaded
 171    (=the ones activated in AHC.cfg)
 172 
 173    runStart -t ahcCmLed -w
 174 
 175    Adjust the LED amplitude from the Slow Control such that the SiPM
 176    signal is not saturated
 177 
 178    runStart -t ahcCmLedHoldScan -v 25
 179 
 180    ahcBinHst +H -s 5 -f 10000000 320275   (adjust slot, FE and run number)
 181               ^ 
 182             hold
 183             mode
 184                 
 185 
 186    start ROOT in the same directory, enter ".x holdMulti.c(0)" at ROOT
 187    prompt, the argument is the FE. 
 188    Find the hold from the printed messages and put it to
 189    AHC.cfg. Also change Vcalib for Calib.Mode to 42000 (28000 for the
 190    second CMB series (CMBs>20)) in AHC.cfg.
 191 
 192    Activate the new Vcalib value:
 193        shutDown
 194        startUp
 195 
 196 6. Tuning of LED amplitudes (1.5 hours)
 197 
 198    runStart -t ahcCmLed -w
 199 
 200    activate DAQ Vcalib: activate "Ampl Vcalib, width DAC" on Slow Control
 201 
 202    adjust scope horizontal range to see multiplexed SiPM signal
 203    activate mean measurement
 204    set gating to vertical cursors
 205    activate averaging over 128 triggers in the "Acquire" menu.
 206 
 207    use first trimmer to adjust LED intensity: counter-clockwise
 208    increases amplitude
 209 
 210    The cursors are used to select the channels which enter the mean calculation.
 211    Increase the LED intensity and see which channels belong to the LED
 212    that is currently trimmed; adjust gate accordingly.
 213 
 214    Decrease the LED intensity to a mean pedestal value. 
 215    Increase the LED intensity so that the mean is slightly higher than
 216    the pedestal. Typical mean pedestal values are in the range of
 217    30-150mV. Mean values where single pixels can be seen are typically
 218    25-80mV higher than the pedestal mean. You have to experiment.
 219    To check if the setting is correct, take a run with 8000 events:
 220 
 221    runStart -t ahcCmLed -e 8000
 222 
 223    Convert the binary file to a ROOT file and move to LED analysis directory:
 224    Example (you might have to adapt the analysis directory):
 225       ahcBinHst -s 5 -f 10000000 320275
 226       mv allChannels.root ~/analysis/LEDanalysis/data/allChannels_slot5_fe0.root
 227 
 228    Analyse the data:   
 229       start ROOT in ~/analysis/LEDanalysis
 230 
 231       use analyse(...) to analyse a single LED
 232       the syntax is displayed when starting ROOT
 233       
 234       The light setting is fine when the first
 235       three peaks (0, 1 and 2 pixels) are at
 236       approximately the same amplitude.
 237 
 238    Readjust the amplitude using the trimmer if necessary
 239    When done with this LED connect analogue out cable to next
 240    HAB and tune the next LED. Note: the pattern for the coarse
 241    modules is (see the file LED2chan_coarse.dat in the LED analysis
 242    directory, format: chip chan LED): 
 243 
 244        LED   HAB
 245         0     0  
 246 	1     1
 247 	2     2
 248 	7     3
 249 	8     8
 250 	9     9
 251        10    10
 252        11    11	
 253    
 254    When done with all LEDs take a run with 30k events and use
 255    loop(...) in ROOT to produce a postscript file in the ps
 256    subdirectory with all SiPM spectra. Check the peaks and readjust if
 257    necessary.
 258 
 259 
 260 
 261 
 262 
 263    
 264 
 265 
 266 
 267    
 268 
 269    
 270 
 271 
 272        
 273 
 274 
 275 
 276        

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