FWD Meeting, Torino, June 16th, News from Cracow on the forward tracking J. Smyrski Institute of Physics UJ Tests of CARIOCA and LUMICAL preamplifiers Tests of prototype module Simulations with GARFIELD and PANDAroot Geometry of the tracking stations New design of end-plugs

2 Charge injector Q = V/56 x 1.2 pF TF = ~600ns TR = 1ns f = 1 kHz (V=100 mV  Q=2.1 fC) C=1.2 pF V R 50 V/56 Cdet

3 CARIOCA threshold characteristics discr. threshold = 820 mV, C det = 0 pF 180 mV  3.9 fC ±20 mV  ±0.4 fC

4 CARIOCA - charge vs discr. threshold CARIOCA amplification depends strongly on the detector capacitance

5 New PCB Discrimination threshold and test pulses controlled remotely

6 LUMICAL threshold characteristics Output pulses with 1 fC injected

7 module on stand gas connection preamp. connection New 4-layers PCB with 2 grounding layers horizontal bar to assure planarity of the module Straw module bends in the direction perpendicular to active area – mechanical element to assure planarity might be needed Effect of preamp. oscillations reduced

8 Straw HV characteristics with CARIOCA 55 Fe lowest possible threshold with no oscillations = 880 mV  ~10 fC Vthr= 880 mV 60 Co Working voltage of ~1800 V might be sufficient for tracking of charged particles

9 Straw electrical properties Z det ( ; >50 MHz)   L/C = 373 

10 FEE connection to detector CARIOCA ? ?

11 Termination of straws R2 =  Ω (resistor removed) R1 = 370 Ω R1 = 0 Ω R2 = 370 Ω Termination not needed (tests with CARIOCA discr. threshold = 880 mV)

12 HV characteristics with LUMICAL Minimal working voltage corresponding to 100% efficiency for 55 Fe was by about 100 V smaller with LUMICAL than with CARIOCA Lower (< 10 fC) threshold settings were not possible due to problem with ringing

13 Effect of „double threshold crossing” Long pulse tail + ringing  additional discriminator response

14 Gas gain gain= I / (N*Q) Current I and counts N measured with 55 Fe (primary charge Q ≈ 220 e)

15 Time over threshold measurement - simulations with GARFIELD 0.8 GeV/c proton Ar-CO2 (90:10) at 2 bar, HV=1500 V discr. threshold Transfer function 20·t·exp(-20·t), t[μs]

16 Time over threshold spectra one strawaverage from 20 straws 0.8 GeV/c protons 0.8 GeV/c pions 6 σ separation

17 Forward tracking simulations - choice of wire inclination Particles: 0.5 GeV/c muons Dipole magnet setting: for 7.8 GeV/c beam 5 deg. inclination chosen

18 Definition of local coordinate system for straw module y’ = 0 is a symmetry plane of the module - it lies in the middle of length of the module Position of the module center (x’=y’=z’=0) is given in the PANDA reference frame (x,y,x) with the origin in the target point For all modules z’ is parallel to z Module inclination angle  is the angle between y and y’; right handed rotation around z corresponds to positive angles Straw length l is by 2 cm longer than the expected sensitive length of straws (it takes into account end plugs (0.8 cm cm) and area of distorted electric field (0.2 cm +0.2 cm)

19 Inclination, coordinates and length of straw modules

20 Active areas Total number of modules: 336 Total number of straw tubes: 336 x 32 = Tracking station 1, 2

21 Openings for beam pipe Tracking station beam pipe  proposed opening x-y 1, mm 110x110 mm 2 3, 4 96 mm 104x104 mm 2 5, mm 166x166 mm 2

22 Space available for frames of tracking stations inside the dipole magnet gap

23 Tracking stations inside the dipole magnet gap double layer 12341’2’3’4’ preamp. card support frame

24 Proposed end-plugs (option without springs) no springs; grounding of straws by direct gluing to conductive pads no plastic pipes for gas; steel pipes connecting straw volumes with gas distribution channels gas gas tube gas channel print for grounding straws plastic socket brass socket crimp pin centering ring

25 Gas distribution gas inlet gas outlet distribution channel collecting channel

26 Backup slides

27 Alternative solution - application of springs at one end of straws space for spring

28 Quality control (single straws) Wire tension (frequency = nominal ±10%) Isolation (current < ~1nA at 1500 V)

29 Quality control (modules) Gas tightness (pressure drop in time) HV characteristics with 55 Fe (steepness of the slope (noise) and width of the plateau) Position of the sense wire and of the straw (x-ray measurements)