===========
                             LEVEL2 data
				          *
                              (R-2.00)
                             ===========

LEVEL2 nt-uple structure:

 ******************************************************************
 * Ntuple ID = 22     Entries = 5680      LEVEL2
 ******************************************************************
 * Var numb * Type * Packing *    Range     *  Block   *  Name    *
 ******************************************************************
 *      1   * L*4  *    1    *              * EVENT    * GOOD2
 *      2   * I*4  *         *              * EVENT    * NEV2
 *      1   * U*4  *    6    * [0,50]       * CPU      * PKT_TYPE
 *      2   * I*4  *         *              * CPU      * PKT_NUM
 *      3   * I*4  *         *              * CPU      * OBT
 *      4   * U*4  *    6    * [0,50]       * CPU      * WHICH_CALIB
 *      1   * I*4  *         * [0,50]       * TRACKS   * NTRK
 *      2   * U*4  *    6    * [0,50]       * TRACKS   * IMAGE(NTRK)
 *      3   * R*4  *         *              * TRACKS   * XM(6,NTRK)
 *      4   * R*4  *         *              * TRACKS   * YM(6,NTRK)
 *      5   * R*4  *         *              * TRACKS   * ZM(6,NTRK)
 *      6   * R*4  *         *              * TRACKS   * RESX(6,NTRK)
 *      7   * R*4  *         *              * TRACKS   * RESY(6,NTRK)
 *      8   * R*4  *         *              * TRACKS   * AL(5,NTRK)
 *      9   * R*4  *         *              * TRACKS   * COVAL(5,5,NTRK)
 *     10   * R*4  *         *              * TRACKS   * CHI2(NTRK)
 *     11   * U*4  *    1    * [0,1]        * TRACKS   * XGOOD(6,NTRK)
 *     12   * U*4  *    1    * [0,1]        * TRACKS   * YGOOD(6,NTRK)
 *     13   * R*4  *         *              * TRACKS   * XV(6,NTRK)
 *     14   * R*4  *         *              * TRACKS   * YV(6,NTRK)
 *     15   * R*4  *         *              * TRACKS   * ZV(6,NTRK)
 *     16   * R*4  *         *              * TRACKS   * AXV(6,NTRK)
 *     17   * R*4  *         *              * TRACKS   * AYV(6,NTRK)
 *     18   * R*4  *         *              * TRACKS   * DEDXP(6,NTRK)
 *      1   * I*4  *         *              * SINGLETS * NCLSX(6)
 *      2   * I*4  *         *              * SINGLETS * NCLSY(6)
 ******************************************************************
 *  Block   *  Entries  * Unpacked * Packed *   Packing Factor    *
 ******************************************************************
 * EVENT    *  5680     * 8        * 5      *       1.600         *
 * CPU      *  5680     * 16       * 10     *       1.600         *
 * TRACKS   *  5680     * 22004    * Var.   *    Variable         *
 * SINGLETS *  5680     * 48       * 48     *       1.000         *
 * Total    *    ---    * 22076    * Var.   *    Variable         *
 ******************************************************************
 * Blocks = 4            Variables = 26      Max. Columns = 5519  *
 ******************************************************************


The EVENT block stores the global event flag GOOD2 and the event counter NEV2.

The CPU block stores the event tag extracted from the physics-packet 
CPU-header (PKT_TYPE, PKT_NUM, OBT) and a variable that relates each event to 
the calibration parameters (WHICH_CALIB). 
(If WHICH_CALIB=0 (missing calibration) then GOOD2=.FALSE.)

The TRACKS block stores track information: 
  NTRK           - number of identified tracks (in case the Y ambiguity is not
                   solved both the track images are stored)
  IMAGE(NTRK)    - ID of the track image (=0 if no image)
  XM(6,NTRK)     - measured coordinates associated to the track
  YM(6,NTRK)       '
  ZM(6,NTRK)       '
  RESX(6,NTRK)   - spatial resolution associated to each coordinate
  RESY(6,NTRK)     '
  AL(5,NTRK)     - TRACK PARAMETERS: X0,Y0,sin(THETA0),PHI0,DEFLECTION 
  COVAL(5,5,NTRK)- Variance/covariance matrix of parameters
  CHI2(NTRK)     - reduced chi^2 of the track 
  XGOOD(6,NTRK)  - flag indicating if a plane was included in the track fitting
  YGOOD(6,NTRK)    '
  XV(6,NTRK)     - calculated coordinates
  YV(6,NTRK)       '
  ZV(6,NTRK)       '
  AXV(6,NTRK)    - calculated angles
  AYV(6,NTRK)      '
  DEDXP(6,NTRK)  - average energy release

The SINGLETS block stores information about those clusters not associated with 
any track: 
  NCLSX(6)       - number of singlets in each plane
  NCLSY(6)         '