diff --git a/jass_pipeline.nf b/jass_pipeline.nf
index 339110645152a49382f14de4d92c7840dc26776f..763a62df596e42eb85078de589720b3400933f37 100644
--- a/jass_pipeline.nf
+++ b/jass_pipeline.nf
@@ -51,8 +51,8 @@ Region_channel = Channel.fromPath(params.region)
 Region_channel2 = Channel.fromPath(params.region)
 
 chr_channel = Channel.from(1..22)
-ref_chr_channel=Channel.fromPath(params.ref_panel+"/ALL_ensemble_1000G_hg38_EAS_chr*.bim")
-ld_channel=Channel.fromPath(params.ld_folder)
+ref_chr_path=params.ref_panel+"/ALL_ensemble_1000G_hg38_EAS_chr*.bim"
+
 
 extract_sample_size_script_channel = Channel.fromPath("${projectDir}/bin/extract_sample_size.py")
 generate_trait_pairs_channel = Channel.fromPath("${projectDir}/bin/generate_trait_pairs.py")
@@ -108,8 +108,8 @@ process Impute_GWAS {
     publishDir "${params.output_folder}", pattern: "imputed_GWAS/*.txt", mode: 'copy'
     input:
         path gwas_files from cleaned_gwas_chr_channel
-        path ref_file from ref_chr_channel.collect()
-        path ld_file from ld_channel.collect()
+        path ref_file from Channel.fromPath(ref_chr_path).collect()
+        path ld_file from Channel.fromPath(param.ld_folder).collect()
     output:
         path "imputed_GWAS/*.txt" into imputed_gwas_channel
         path "imputed_GWAS/*.txt" into imputed_gwas_channel2