TChain *e = new TChain("rqDir/eventTree")
TChain *z = new TChain("rqDir/zip3")

int nsparse = 1

char* datapath ="/data/chocula/fritts/data/k100proc/midasrq/byseries/"

e->Add(Form("%s/%s/umn*root",datapath,"07200724_1546"));
z->Add(Form("%s/%s/umn*root",datapath,"07200724_1546"));

z->AddFriend(e)

TCut crand = "EventCategory" 

z->SetAlias("ffrac","PFOFamps/PTOFamps")
z->Draw("PFOFamps/PTOFamps:PTOFamps",!crand+"ffrac>0&&ffrac<1&&PTOFamps>0&&PTOFamps<1e-6")
// 60keV line is very sloped suggesting bad channel balancing
TCut cf = "ffrac>0.5"

z->Draw("PTOFamps>>h(200,0.0e-6,0.5e-6)",!crand+cf)
z->SetAlias("PTOFkeV","PTOFamps*59.54/0.185e-6")
z->SetAlias("PTOF0keV","PTOFamps0*59.54/0.185e-6")
z->Draw("PTOF0keV",crand)
z->Draw("PTOF0keV>>h(100,-20,20)",crand)
h->Fit("gaus") // Sigma        6.25435e+00   2.47262e-01