1 NA58 RICH Test Beam T10 sept.2014 Fulvio Tessarotto – Stefano Levorato Partecipants: Alessandria, Aveiro, Budapest, Calcutta, Freiburg, Liberec, Prague, Torino, Trieste 300 x 300 mm 2 hybrid Photon Detectors Components and tests Assembling and TB installation Detector performance Time response The 600 mm x 600 mm PD’s for RICH-1 Gain ~ 130K

2 CERN, COMPASS TB meeting, 6/11/2013 Hybrid detector for comparison: Triple THGEM MICROMEGAS stage Bulk Micromegas: Courtesy of the Saclay colleagues FIRST PROTOTYPE Small area hybrid detector

3  Two photon detectors with the same basic stucture:  2 THGEMs  the first has a CsI photo-converting layer  The two THGEMs are positioned to provide hole staggering  lower charge density and higher stability  1 bulk MICROMEGAS  Standard Detector: MICROMEGAS standard, HV on the micromesh  Capacitive Detector: MICROMEGAS with resistive/capacitive anode  micromesh at ground 10 mm 3 mm 3.0 mm 128  m THGEM MESH THGEM CsI coating Structure of the 300 x 300 mm 2 hybrid PD 12mm x 12 mm anodic pads THGEM sectors THGEM parameters: thickn. = 0.4 mm, hole diam.= 0.4 mm, pitch= 0.8 mm

4  Scheme (not to scale)  Only 1 single pad shown  Principle  Blue pad at HV via internal connection  Resistive (individual pad resistor at the PCB rear surface)  Red pad: signal induced by RC coupling PCB 0.10 mm fiberglass Metallic pads The resistive/capacitive anode HV to blue pad through the hole of red pad Resistor arrays (from HV line to blue pads) Signal connectors (from red pads)

5 Mesh preparation at Seritech Bulk Micromegas produced at CERN Fulvio TESSAROTTO Production of 300 mm x 300 mm hybrid PDs Anode wire frames and chamber frames in Trieste

6 Fulvio TESSAROTTO Assembly and test box

7 MICROMEGAS + 1 THGEM only (before mounting the CsI coated THGEM in the Chamber) 55 Fe main peak  total gain 55 Fe escape peak 55 Fe main peak, MICROMEGAS only  MICROMEGAS gain from the ratio  THGEM effective gain Test of the Chamber with 55 Fe

8 THGEM HV scan detector response with 55 Fe MICROMEGAS + 2 THGEMs ( before CsI coating)

9 Assembling the PD in the glove-box

10 … special tools …

11 … cooperation …

12 … attention …

13 … concentration …

14 … coordination …

15 CERN PS, T10 Trigger and support structure are the same as in 2012 In the Test Beam area

16 Installation Phase

17   Great global and human effort from all participating Institues  8-10 physicists every day  Shifts: 24/24   Beam (5 GeV π - ), gas (Ar/CH4 30/70) and complex installation o.k.  Quite stable beam, trigger rates, other services   Problems with HV power suppliers  CAEN N1471 H (remote control and high resolution current reading) introduces more noise than CAEN 471 A   Electronic noise was a nightmare  The large capacitance of the MICROMEGAS plays a role X General remarks

18   Amplification chain:  CREMAT CR-110 (111)  ORTEC amplier model 450   Acquisition:  GANDALF (Freiburg)  Groups of 16 or 32 pads Analogic readout

19 Gain ~ 12.5K (16 pad: the trigger covers a larger area) Gain ~ 3.8 K (32 pad: trigger fully included  100% efficiency for MIPs) Landau evolution with voltage MICROMEGAS: 600 V 650 V 675 V pedestal m.i.p. amplitude spectra

20 Gain ~ 130K Č photon Single Cherenkov photon amplitude spectra beam ~ 5 times the gain for the same trip rate as in 2012

21 Charged particle ionization collection depends on the drift field: relevant for m.i.p. suppression E Drift = -100 V/cm E Drift = V/cm vs E Drift vs E drift, both detectors m.i.p. drift scan

22 n. of counts above a fix threshold normalized to n. of triggers vs E Drift Integral of the exponential spectrum normalized to n. of triggers vs E Drift, two different ranges are fitted Cherenkov photons drift scan The number of detected photoelectrons depends on the drift field: photoelctron detection efficiency to be maximized Two algorithms to count the detected photoelectrons preliminary

23 Interceptor position scan The remotely controlled movable interceptor allows for changing the number of photons in the corona The dependence is linear as expected

24  Readout chain: same as RICH-1 – MAPMT  C-MAD  Roof  DREISAM card  No need for FE protection boards – 2012:  Fighting against noise during the entire Test  Impossible to run with all channels together  Very high thresholds ( from 6 to 15 fC) (~3 fC in 2012 Test Beam) Digital readout

25 OFF Log scale 2012 for comparison Digital images 2012 for comparison

26 9 ns Very clean time spectra For comparison: triple THGEM time spectra from 2012 test beam Capacitive/resistive hybrid PD lower gain

27 23% fraction of events outside the gaussian peak : 19% 11% 6% G = 2.0 * 10 5 G = 1.1 * 10 5 G = 0.9 * 10 5 G = 1.4 * 10 5 Fulvio TESSAROTTO Small prototype: time response study (2011)

28 Time resolution

29   Both detectors performed at the Test Beam as they did in the Lab.   The resistive/capacitive hybrid allows to operate the MICROMEGAS at voltage bias which are 100 V larger than for the standard one   Larger gain with less THGEM voltage and higher stability  V to MICROMEGAS  factor 10 in gain  No other large MPGD has ever been operated with a beam at 10 5 gain  Excellent time response  Nice device suitable for single Cherenkov photon detection   To be understood:  Read-out & noise  HV powering system Preliminary conclusions

30 Next step: 600 mm x 600 mm

31 Production of the THGEMS 600x300 stripping dry-film development etching image transfer

32 Production of the THGEMS 600x300 multi-spindle drilling

33 the Micromegas 600x300 connector and anode HV sideMicromegas side (protected)

34 Fulvio TESSAROTTO 600 mm x 600 mm hybrid PD

35 Fulvio TESSAROTTO The 600 mm x 600 mm hybrid PD prototype

36 Fulvio TESSAROTTO The 600 mm x 600 mm hybrid PD prototype

37 Fulvio TESSAROTTO The 600 mm x 600 mm hybrid PD prototype

38 Fulvio TESSAROTTO The 600 mm x 600 mm hybrid PD prototype

39 Fulvio TESSAROTTO The 600 mm x 600 mm hybrid PD prototype

40 Fulvio TESSAROTTO The 600 mm x 600 mm hybrid PD prototype

41 Fulvio TESSAROTTO The 600 mm x 600 mm hybrid PD prototype

42 Fulvio TESSAROTTO large fused silica windows field and drift wire frame PD support frames lenses and MAPMTs THGEMs +CsI and Micromegas The MAPMT + hybrid PD chamber for RICH-1

43 radiator: C 4 F 10 5 m 6 m 3 m MWPC’s + CsI UV mirror wall Al vessel radiator gas: C 4 F 10 PMTs beam pipe COMPASS RICH-1 PD upgrade

44 radiator: C 4 F 10 5 m 6 m 3 m MWPC’s + CsI UV mirror wall Al vessel radiator gas: C 4 F 10 PMTs beam pipe THGEMs + CsI COMPASS RICH-1 PD upgrade Foreseen for 2016