Al-core TPC collection plane test results CENBG option J. Giovinazzo, J. Pibernat, T. Goigoux (R. de Oliveira CERN)

Transcription

1 Al-core TPC collection plane test results CENBG option J. Giovinazzo, J. Pibernat, T. Goigoux (R. de Oliveira CERN) Collection plane R&D Prototypes characterization - collection plane tests - individual pads signal ACTAR TPC collaboration meeting GANIL November 18-20

2 Organization GANIL CENBG (IPNO) Leuven Santiago de C. ERC funding (GANIL) shared electronics detector developments - gas chamber (reaction / decay) - collection plane IRFU CENBG GANIL MSU CENBG implication decay chamber data analysis collection plane (R&D) Electronics development ANR funding ( ) funding (complementary): - Aquitaine region - IN2P3 R&D programs - Univ. Bordeaux (T.G. thesis)

3 Collection plane principle final detector(s) pads (2x2 cm 2 ) - mechanical issues: sealing, deformation (vacuum) - signals extraction through the plane ACTAR-TPC demonstrator(s) - 2 pad planes prototypes (2048 pads) PCB + micromegas (amplification) - standard option (GANIL / IPNO) standard PCB, small connectors for signal extraction through flange holes - CENBG option direct connection through PCB aluminum core PCB resin (isolation) micromegas metal core connectors known technology fragile (connectors), signal routing conceptually extremely simple mechanical constraints complex realization process unknown feasibility and response

4 Prototypes realization PCB realization process collaboration with CERN PCB workshop (R. de Oliveira) - drilled Al (high resistance) plane - PCB layers - connectors soldering - micromegas (bulk, 128 µm) collection plane prototypes process test (256 pads prototype) several issues: PCB bubbles, soldering quality, 2048 pads prototype first attempt: - soldering process not yet satisfying - problems with micromegas realization test prototype #1 micromegas last prototype structure analysis (FEDD) final prototype - PCB CERN - FEDD company realization tests OK! prototype cost 4000

5 Characterization set-up demonstrator set-up - full drift cage (GANIL design) - not yet in effective operation (problem of parasitic signal from HV) - required for tracking tests (uniform electric field) test set-up: simple drift high voltage micromegas drift ( 2-5 cm) 350 to 600 V 1000 to 2000 V signals - pads grounded (ground connectors) except 1 row: 64 pads grouped together with standard charge P.A. - mesh signal on standard charge P.A. current test limitation - not optimal charge P.A. (too low gain) - non-uniform electric field

6 2.7 kev 5.9 kev Pad plane characterization: X-rays from 55 Fe source micromegas mesh signal uncollimated source on top of the drift volume HV mesh = 570 V HV drift = 1000 V trigger 64 pads (grouped) mesh signal 1 row of 64 pads connected together coinc. measurement simulation pad plane resolution 6 kev: % non collimated source includes the pads collection variations

7 Pad plane characterization: 3-alpha source collimated Am-Cm-Pu source on the side of the drift volume (increased drift gap: 5 cm) limited test: energy loss before active zone degraded energy trigger 64 pads (grouped) mesh signal coincident mesh pads group signals HV mesh = 370 V HV drift = 1500 V unexpected shift collection inhomogeneity? bad virtual ground (PAC)? need for a full test set-up all events gate E pads > 200

8 Connectors to readout electronics (GET / AsAd) test setup (no drift cage) AsAd board bad E field!!! ZAP v0 GANIL acq. R-CoBo E mesh (standard PAC) E pads (64 grouped pads; standard PAC) S pad [i] (4x64 pads; AsAd) one AsAd v2.1 (serial id C9B) R-CoBo read-out ZAP v0 test prototype pseudo-common dead-time (mesh trigger) main trigger from Ganacq (TGV) forced long fix DT (5 ms) AsAd 4x64 pads 5 ms veto v R-CoBo mesh trigger individual pads 64 pads (grouped) mesh signal

9 RMS measurements: AsAd + ZAP (not coupled to detector) F W = 25 MHz ZAP v1 L+R

10 RMS measurements: AsAd + ZAP + detector baseline 50 MHz, 120 fc range and 502 ns peaking time baseline RMS RMS with phase effect correction RMS with FPN correction Test-bench (AsAd alone): AsAd + ZAP + detector: RMS 4 coder units RMS 6 coder units ( depends on peaking time) (preliminary ZAP version, bad shielding side) same as noise test of AsAd + ZAP (no additional noise from detector???) channels (1-32) & (33-64) difference (already seen with no detector) to be tested with other peaking times

11 Individual pads signal shift due to E field deformation source position event signal processing (reconstruction) response function (standard) filtering Q rec (fc) A max (coder) s raw t (c.u.) s cor t (c.u.) i rec t (na) T rec (µs) note: induced signal (negative) from mesh not observed when pad is not hit (ref. to GANIL tests on prototype, 2014)

12 grouped pads signal Mesh and pads correlated signals L X > 7 pads 3-alpha lines mesh signal summed individual pads charge condition: long enough track L X > 7 pads no grouped pads signal E pads < 150 c. u. all events condition grouped vs individual pads: 3-alpha lines visible longest tracks: parallel to X-axis constant energy shared between grouped pads & AsAd pads

13 grouped pads signal Signals interpretation partial measurement (only pads) fully understood result (a) partial or all signal collected on AsAd pads (b) partial signal collected on grouped pads (c) all signal shared between AsAd and grouped pads (c) (b) (a) summed individual pads charge (AsAd) (a) (b) (c)

14 GANIL (suspecting ground connectors) tests at CENBG (after scannin) 3-alpha collimated source position (A) alpha source on top of problem position (B) alpha source on top of clean detector zone pos. A pos. B talk from J. Pancin connector in scan configuration confirm signal collection problem in position A

15 GANIL (suspecting ground connectors) tests at CENBG (after scannin) 3-alpha collimated source position (A) alpha source on top of problem position (B) alpha source on top of clean detector zone pos. A pos. B talk from J. Pancin connector in scan configuration confirm signal collection problem in position A flip of groups of connectors signal is OK problem from connectors not from collection plane

16 collection pad plane feasibility & robustness ok (several connectors insertions and extractions) 6 kev 22 % 3-alpha source: ok (limited analysis) ZAP connectors noise comparable to GANIL/IPNO options (for large peaking time values ) almost no additional noise from detector coupling pads signals Summary no drift cage (distorted E field) 3-alpha test: resolution OK test with full system (2048 channels, drift cage) required

17 thank you for your attention