60 likes | 174 Views
Shading in PISA. Takao. Status and Issue. Implementing shade geometrically (or visually) in PISA was not difficult An issue was that Cherenkov photons were not absorbed at shades. Maxim is also aware of same type of problem
E N D
Shading in PISA Takao
Status and Issue • Implementing shade geometrically (or visually) in PISA was not difficult • An issue was that Cherenkov photons were not absorbed at shades. • Maxim is also aware of same type of problem • Amount of photon conversion did not change at all when Maxim added FEM to HBD • Sound somewhat bigger problem • Geometry nest in HBD: • HALL (PHENIX) HBDG (Gas Volume) TISO (HBD Mother frame) • Most of HBD components (HV panel, GEM, etc.) attribute under “TISO” • I added shade under “TISO”, but no particle including photon interact with the shade • A solution found by Maxim was to expand “GSM”(Gas volume include CsI of Top GEM and Mesh) that were already defined, and assign shade under GSM. • Maxim confirmed that the shade absorbs cherenkov photons • Now, another problem happened. • Loss of photons is 40% with 2.5cm height shade with 2.5cm*2.5cm spacing!!
View of Shading No Shade Shade 1.5cm height, 1.5cm*1.5cm spacing Shade 2.5cm height, 2.5cm*2.5cm spacing
Seen from outside PHENIX • Left: NO shade • Right: 2.5cm shade with 2.5cm*2.5cm spacing
Event display of one “same” electron • Cherenkov photons emitted from electrons seem to be reduced if shade is located? 2.5cm means: 2.5cm height, with 2.5cm*2.5cm spacing. Same for 1.5cm. For 1000 same electrons: Cherenkov photons I get at CsI No Shade: 19980, Shade 2.5cm: 12319, Shade 1.5cm: 12547
So.. • I don’t think 40% loss is right. We might be screwed up something on geometry definition in PISA? • Sasha’s estimate was 3% loss, and would not change as long as height/spacing ratio holds. • This simple geometrical estimate should give correct answer to more than first order! • PISAEvent.root for each case are placed in the same directory • Also, the codes modified are placed here as well • Hbd.f, phnx.par, phenix.kumac • Welcome for help, comment and jump-in!