Physics program

Modified from Main.Physics_program


SLABs: to be completed.

ASU: Most recent reviews of the devices are in


SENSORS: one silicon sensor has a size of 89.960 +/- 0.040 mm, and it is a matrix of 16x16 pixels with a pitch of 5.530 mm. Ie. at the periphery one has (89.960 - 16*5.530)/2 = 0.74 mm wide guard ring. The design is a know-how of Hamamatsu, the guard ring should partially be efficient.

In principle, if necessary, the "effective" active area of peripheral pixels may be estimated from occupancy distributions: it should be a smooth continuation from inner sensor regions (eg. with effectively wider peripheral pixels, they should get more hits and produce some little amount of discontinuity).

In addition, on the PCB there is a 0.1 mm gap between the sensors in the center.


Beam cracteristics are available here

Beam rate is limited to 5 kHz (2 GeV electrons and target 1)

Installation and commissioning

  • Setup of stack with 7 layers including infrastructrure as computing
  • Validation of noise levels and trigger thresholds, adjustments if necessary

Scans w/o tungsten

  • Scan with step size of 2cm in x and y direction
  • 10000 - 20000 acquisitions at each point
  • 1000+ events per cell. => 16000 events per 2×2 cm²
  • Option: check the mip calibration by rotating the structure by 45° => 40% increase in MPV.
  • we measure with an acquisition window of ~2.5ms and the beam rate at DESY at 3 GeV is of the order of a few kHz.
    This means we get a few events per acquisition, let's say pessimistically one event/acquisition.
  • If we take data with 5Hz spill frequency then 20000 acquisitions take about an hour (a bit less),
  • a step size of 2cm means that we take 8x8 = 64 points (if no points at the outer borders of a layer).
    • for a beam spot of 2 cm, we cover 16 cells of 5×5mm² → 1250 mips per cell.
  • This means that the scan takes us about four days assuming 16 hours of data taking/day. This is generously calculated.
  • Given the beam spot size of 3cm (in diameter) this should give a large sample to select tracks for uniformity tests and MIP calibration.
    Better more than less ...

Calorimeter program

  • To be done: optimal W distribution (24 X0)
  • Core program 2-5 GeV in step sizes of 1 GeV, 20000 acquisitions
  • Trying to get samples at 5 and 6 GeV
    • rates at 5 GeV depend a lot on the DESY-II beam conditions: in practise require 7 GeV in DESY-II
  • Optionnally: run with ≠ W disctribution (2/3 layers with single W layers+ 1/3 layers with double amount of W).
Rates and 5 GeV and 6 GeV are about 3–200 Hz and 1 Hz (!) but in order to get a sample of about 10000 events, runs of about 2-3 hours are needed. There is nothing that speaks against it, but the 'real' events compete with the residual noise rate. We have to assure good data quality checks during the data taking.

Scan close to the center (5 points in dice-5 conditions) ? depends on beam-size spot.

Magnetic field

  • Move racks to PC24.1
  • Test without and with magnetic field.
  • high stat runs (~100000)
  • carefull check of beam spot size & position!
* Note to take into account about an hour to ramp up and down the magnet

Tentative schedule

Program as a google sheet wiith rates & time estimations.

Some comments and remarks:

- The program is in general planned very generously
- In the scan w/o tungsten we can increase the acquisition rate or lower the number of scan points to save time
- I have aligned the program on days but this is of course not necessary, once a program point is finished we can start immediately a new one after the necessary changes
- At the end of the first scan w/o tungsten we should decide to add one or more layers to the setup and repeat the scan, maybe with fewer scan points.
- Night shifts can be arranged optionally in order to complete the program

-- VincentBoudry - 2015-10-28

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf CAL_12_03_00__V4_Assemblage_Support_Test_2_vue_de_dessus.pdf r1 manage 213.5 K 2017-06-13 - 16:21 VincentBoudry  
PDFpdf ensemble_plateau_test_Calque_1.pdf r1 manage 675.3 K 2015-12-14 - 17:00 VincentBoudry  
PDFpdf ensemble_plateau_test_Calque_2.pdf r1 manage 452.2 K 2015-12-14 - 17:01 VincentBoudry  
PDFpdf ensemble_plateau_test_ind_A.pdf r1 manage 1048.3 K 2016-01-07 - 13:09 VladislavBalagura  
PDFpdf scheme.pdf r1 manage 103.4 K 2016-01-11 - 10:57 VladislavBalagura  
Edit | Attach | Watch | Print version | History: r10 < r9 < r8 < r7 < r6 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r10 - 2017-06-13 - VincentBoudry
    • Cern Search Icon Cern Search
    • TWiki Search Icon TWiki Search
    • Google Search Icon Google Search

    CALICE All webs login

This site is powered by the TWiki collaboration platform Powered by PerlCopyright &© 2008-2021 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
or Ideas, requests, problems regarding TWiki? use Discourse or Send feedback