1 / 11

The first experience with THGEM at PNPI. Status report

The first experience with THGEM at PNPI. Status report. Leonid Kudin (PNPI, Gatchina) CBM Collaboration Meeting, September 25-28, 2007, Dresden. Leonid Kudin, PNPI, kudin@pnpi.nw.ru. What was done ?.

oria
Download Presentation

The first experience with THGEM at PNPI. Status report

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The first experiencewith THGEM at PNPI.Status report Leonid Kudin (PNPI, Gatchina) CBM Collaboration Meeting, September 25-28, 2007, Dresden Leonid Kudin, PNPI, kudin@pnpi.nw.ru

  2. What was done ? About 40 of THGEM sampleswere produced at PNPI in the process of THGEM technology improvement. Part of them passed first tests and are ready now for detail investigations

  3. TGEM samples for testsand analysis • Pitch from 0.7mm to 1.2mm • GEMs material: FR4, G10; • Sensitive area: 50x50 sq. mm;

  4. Prototype construction • Monolithic aluminium box contains: • 6 HV inputs plus HV dividers; • 6 HV capacitors are in the gas volume; • Stackable electrode’s construction; • Gas inlet-outlet; • Rubber ring for gas sealing; • Two output connectors for electronic; • The part of box’s elements are removable to provide flexibility of construction In the process. There is no gas leaks detected. The box constructionprovides THGEM study and to work with THGEM’s material thickness till 1.5-2mm

  5. TGEM production problems To the moment we have understanding , that technological problems are the most important problems in THGEM production. Therefore the main efforts and time were gave to its solutions. One of the problems is a problem of providing of concentricity between THGEM’s hole and protection rim to have a good HV parameters.

  6. Hole & rim eccentricity Rim Hole Critical zone ! (GEM HVis limited) Drill bit tail precession • 1. Standard procedure of THGEM production: • Photo-mask preparation; • Cooper etching; • Holes drilling • The typical eccentricity ~ 30-70 microns is a result of • drill bit precession, drill machine positioning precision, photo-mask shift… etc. • 2. We used non- standard procedure: • Two stacked plates drilled; • One of the plates was as THGEM plate. • The another one after enlarge drilling was used as photo-mask for rims. • In the process of enlarge drilling a self- centering of drill bit in the enlarging hole has a place . • The typical eccentricity ~ 20-30 microns Drawback: double drilling!

  7. THGEM holes structure Maximum hole diameter 1mm; Maximum protection rim width 100 microns Minimum hole diameter 0.3mm; Minimum protection rim width 50 microns The pitch is from 0.7 to 1.2 mm

  8. Electrical insulation tests THGEM tests • HV tests of the construction elements of the box: • THGEM elements stand up to 6kV relative to GND. The result is OK! There is no sparks. • HV leak current under the normalconditions • (T= 20o C; H=60%) - no more than 20 nA

  9. Signals tests were started 1 week ago.(Very new (preliminary results) The part of THGEMs were tested on operability. RA source: Fe55 Gas mixture: He-80%; CO2-20% Ug=2.05 kV Usg=100mV; Tsg=35ns FWHM;

  10. Signal tests (amplitude spectra) Gas mixture He-80%; CO2-20%; RA source Fe 55; Ua=0.7kV; Uk=3.4kV; Self-triggering data acquisition. TGEM 11: Thickness -0.9mm; Hole diameter -0.3mm; Rim diameter – 0.4 mm One can conclude, that mainly, TGEMs work normally and ready for father detailed investigations.

  11. Our nearest plans • To study: • Electron Transfer Efficiency (ETE); • Effective gain G(HV) • Ion back flow fraction • During investigations TGGEM production will be prolonged (as may be necessary). • We will prolong the technology improvement: • We attend to reach the lock-on between TGEM holes and rims with precision better than 10 micron. Now we have some progress in this direction. We hope, that this task will be completed successfully.

More Related